From 496e0f706b8ad7831bf7189ff9deb8701d2ebc2b Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Mon, 3 Aug 2026 14:40:28 +0200 Subject: KVM: s390: Fix unlikely NULL gmap dereference When creating a new vCPU, kvm_vm_ioctl_create_vcpu() will call kvm_arch_vcpu_postcreate() after the file descriptor for the new vCPU has been created. The new file descriptor has not been returned yet, but a malicious userspace program could try to guess it. If a malicious userspace program manages to start the newly created vCPU before kvm_arch_vcpu_postcreate() is called, __vcpu_run() will try to dereference vcpu->arch.gmap and trigger a NULL pointer dereference. Fix this by adding a new field to struct kvm_vcpu_arch to keep track of the initialization status of the vCPU. Refuse to run a vCPU that is not fully initialized. Fixes: dafd032a15f8 ("KVM: s390: move vcpu specific initalization to a later point") Fixes: e38c884df921 ("KVM: s390: Switch to new gmap") Reviewed-by: Steffen Eiden Reviewed-by: Janosch Frank Reviewed-by: Christian Borntraeger Signed-off-by: Claudio Imbrenda Message-ID: <20260803124040.126471-2-imbrenda@linux.ibm.com> --- arch/s390/include/asm/kvm_host.h | 1 + arch/s390/kvm/kvm-s390.c | 11 +++++++++++ 2 files changed, 12 insertions(+) (limited to 'arch') diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index c172f9b212d1..b4182ca4435f 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -440,6 +440,7 @@ struct kvm_vcpu_arch { bool skey_enabled; /* Indicator if the access registers have been loaded from guest */ bool acrs_loaded; + bool initialized; struct kvm_s390_pv_vcpu pv; union diag318_info diag318_info; struct kvm_s390_mmu_cache *mc; diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 150b5dd2170e..f86b4b0b356f 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -3613,6 +3613,9 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu) if (test_kvm_facility(vcpu->kvm, 74) || vcpu->kvm->arch.user_instr0 || vcpu->kvm->arch.user_operexec) vcpu->arch.sie_block->ictl |= ICTL_OPEREXC; + + /* Pairs with smp_load_acquire() in kvm_arch_vcpu_ioctl_run() and kvm_arch_vcpu_ioctl() */ + smp_store_release(&vcpu->arch.initialized, true); } static bool kvm_has_pckmo_subfunc(struct kvm *kvm, unsigned long nr) @@ -5039,6 +5042,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) kvm_run->kvm_dirty_regs & ~KVM_SYNC_S390_VALID_FIELDS) return -EINVAL; + /* Pairs with smp_store_release() in kvm_arch_vcpu_postcreate() */ + if (!smp_load_acquire(&vcpu->arch.initialized)) + return -EINVAL; + vcpu_load(vcpu); if (guestdbg_exit_pending(vcpu)) { @@ -5523,6 +5530,10 @@ long kvm_arch_vcpu_ioctl(struct file *filp, long r; u16 rc, rrc; + /* Pairs with smp_store_release() in kvm_arch_vcpu_postcreate() */ + if (!smp_load_acquire(&vcpu->arch.initialized)) + return -EINVAL; + vcpu_load(vcpu); switch (ioctl) { -- cgit v1.2.3 From f8e370058e9e1396fea1a8d11906fa92ec9bad88 Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Mon, 3 Aug 2026 14:40:29 +0200 Subject: KVM: s390: Do not free SCA if it was not allocated If VM creation fails early in kvm_arch_init_vm(), the cleanup code tries to free up the SCA, even though the address is 0. Due to using free_pages_exact(), only the first page is skipped, accidentally freeing pages 1, 2, and 3. Fix by checking whether the pointer is NULL before attempting to free the SCA in sca_dispose(). Fixes: e72753ed1267 ("KVM: s390: Use ESCA instead of BSCA at VM init") Signed-off-by: Claudio Imbrenda Message-ID: <20260803124040.126471-3-imbrenda@linux.ibm.com> Reviewed-by: Christian Borntraeger Reviewed-by: Janosch Frank --- arch/s390/kvm/kvm-s390.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index f86b4b0b356f..1b3290a5ad1a 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -3247,7 +3247,8 @@ static void kvm_s390_crypto_init(struct kvm *kvm) static void sca_dispose(struct kvm *kvm) { - free_pages_exact(kvm->arch.sca, sizeof(*kvm->arch.sca)); + if (kvm->arch.sca) + free_pages_exact(kvm->arch.sca, sizeof(*kvm->arch.sca)); kvm->arch.sca = NULL; } -- cgit v1.2.3 From b050f741fd0d636f2daab72b74aeccea97abdb5f Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Mon, 3 Aug 2026 14:40:30 +0200 Subject: KVM: s390: Fix kvm_s390_vcpu_unsetup_cmma() In some cases kvm_s390_vcpu_unsetup_cmma() can be called with a 0 cbrlo; in such cases, if running with V != R, free_page() will attempt to free physical page 0. Fix by freeing cbrlo only if it's non-zero. Fixes: b31605c12f4e ("KVM: s390: make cmma usage conditionally") Fixes: 29b40f105ec8 ("KVM: s390: protvirt: Add initial vm and cpu lifecycle handling") Signed-off-by: Claudio Imbrenda Message-ID: <20260803124040.126471-4-imbrenda@linux.ibm.com> --- arch/s390/kvm/kvm-s390.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 1b3290a5ad1a..9be27db0a21e 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -3678,7 +3678,8 @@ static void kvm_s390_vcpu_crypto_setup(struct kvm_vcpu *vcpu) void kvm_s390_vcpu_unsetup_cmma(struct kvm_vcpu *vcpu) { - free_page((unsigned long)phys_to_virt(vcpu->arch.sie_block->cbrlo)); + if (vcpu->arch.sie_block->cbrlo) + free_page((unsigned long)phys_to_virt(vcpu->arch.sie_block->cbrlo)); vcpu->arch.sie_block->cbrlo = 0; } -- cgit v1.2.3 From a0496b40a4ab346052aaa59a5163c10224dda01f Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Mon, 3 Aug 2026 14:40:31 +0200 Subject: KVM: s390: Fix overclearing ESCA in case of error If an attempt is made to create a vCPU with an already existing ID, the duplicated vCPU will be destroyed. When destroying a vCPU, its ESCA entry will be cleared. In the above scenario, the spurious duplicate vCPU is destroyed, but the ESCA entry corresponding to the original vCPU is cleared. Fix by skipping clearing the ESCA entry if the vCPU creation was not successful, i.e. if the vcpu->arch.initialized is still zero. Reviewed-by: Janosch Frank Signed-off-by: Claudio Imbrenda Fixes: abf4a71ed95f ("KVM: s390: Unlink vcpu on destroy - v2") [ Added Fixes tag while picking -- Claudio ] Message-ID: <20260803124040.126471-5-imbrenda@linux.ibm.com> --- arch/s390/kvm/interrupt.c | 2 +- arch/s390/kvm/kvm-s390.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'arch') diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 7514d9e2403c..bb4e72466043 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -86,7 +86,7 @@ static void sca_clear_ext_call(struct kvm_vcpu *vcpu) struct esca_block *sca = vcpu->kvm->arch.sca; union esca_sigp_ctrl *sigp_ctrl = &sca->cpu[vcpu->vcpu_id].sigp_ctrl; - if (!kvm_s390_use_sca_entries()) + if (!kvm_s390_use_sca_entries() || !vcpu->arch.initialized) return; kvm_s390_clear_cpuflags(vcpu, CPUSTAT_ECALL_PEND); diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 9be27db0a21e..5b2727d7dfd1 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -3462,7 +3462,7 @@ static void sca_del_vcpu(struct kvm_vcpu *vcpu) { struct esca_block *sca = vcpu->kvm->arch.sca; - if (!kvm_s390_use_sca_entries()) + if (!kvm_s390_use_sca_entries() || !vcpu->arch.initialized) return; clear_bit_inv(vcpu->vcpu_id, (unsigned long *)sca->mcn); -- cgit v1.2.3 From d301ade41831e746783bdb697fae3afba47841ba Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Mon, 3 Aug 2026 14:40:32 +0200 Subject: KVM: s390: ucontrol: Fix sca_clear_ext_call() When cleaning up a UCONTROL VM, sca_clear_ext_call() will touch memory outside of the allocated ESCA block, and UCONTROL VMs don't even use ESCA. Fix by not touching ESCA for UCONTROL VMs, and fence the KVM_S390_INTERRUPT ioctl altogether. Add extra checks in sca_ext_call_pending() and sca_inject_ext_call() to make sure UCONTROL VMs won't touch ESCA. Fencing does not cause regressions with userspace, since UCONTROL VMs never used KVM_S390_INTERRUPT ioctls. Fixes: 7d43bafcff17 ("KVM: s390: Make provisions for ESCA utilization") Signed-off-by: Claudio Imbrenda Message-ID: <20260803124040.126471-6-imbrenda@linux.ibm.com> --- arch/s390/kvm/interrupt.c | 19 ++++++++++++++----- arch/s390/kvm/kvm-s390.c | 5 +++++ 2 files changed, 19 insertions(+), 5 deletions(-) (limited to 'arch') diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index bb4e72466043..8f24bcd1a6d3 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -45,13 +45,16 @@ static struct kvm_s390_gib *gib; static int sca_ext_call_pending(struct kvm_vcpu *vcpu, int *src_id) { struct esca_block *sca = vcpu->kvm->arch.sca; - union esca_sigp_ctrl sigp_ctrl = sca->cpu[vcpu->vcpu_id].sigp_ctrl; + union esca_sigp_ctrl sigp_ctrl; if (!kvm_s390_test_cpuflags(vcpu, CPUSTAT_ECALL_PEND)) return 0; + if (kvm_is_ucontrol(vcpu->kvm)) + return 0; BUG_ON(!kvm_s390_use_sca_entries()); + sigp_ctrl = sca->cpu[vcpu->vcpu_id].sigp_ctrl; if (src_id) *src_id = sigp_ctrl.scn; @@ -60,13 +63,16 @@ static int sca_ext_call_pending(struct kvm_vcpu *vcpu, int *src_id) static int sca_inject_ext_call(struct kvm_vcpu *vcpu, int src_id) { - struct esca_block *sca = vcpu->kvm->arch.sca; - union esca_sigp_ctrl *sigp_ctrl = &sca->cpu[vcpu->vcpu_id].sigp_ctrl; union esca_sigp_ctrl old_val, new_val = {.scn = src_id, .c = 1}; + struct esca_block *sca = vcpu->kvm->arch.sca; + union esca_sigp_ctrl *sigp_ctrl; int expect, rc; BUG_ON(!kvm_s390_use_sca_entries()); + if (kvm_is_ucontrol(vcpu->kvm)) + return -EINVAL; + sigp_ctrl = &sca->cpu[vcpu->vcpu_id].sigp_ctrl; old_val = READ_ONCE(*sigp_ctrl); old_val.c = 0; @@ -84,10 +90,13 @@ static int sca_inject_ext_call(struct kvm_vcpu *vcpu, int src_id) static void sca_clear_ext_call(struct kvm_vcpu *vcpu) { struct esca_block *sca = vcpu->kvm->arch.sca; - union esca_sigp_ctrl *sigp_ctrl = &sca->cpu[vcpu->vcpu_id].sigp_ctrl; + union esca_sigp_ctrl *sigp_ctrl; - if (!kvm_s390_use_sca_entries() || !vcpu->arch.initialized) + if (!kvm_s390_use_sca_entries() || !vcpu->arch.initialized || kvm_is_ucontrol(vcpu->kvm)) return; + + /* Initialize after the above check, to prevent going out of bounds */ + sigp_ctrl = &sca->cpu[vcpu->vcpu_id].sigp_ctrl; kvm_s390_clear_cpuflags(vcpu, CPUSTAT_ECALL_PEND); WRITE_ONCE(sigp_ctrl->value, 0); diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 5b2727d7dfd1..21574f57be72 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -2934,6 +2934,9 @@ int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) case KVM_S390_INTERRUPT: { struct kvm_s390_interrupt s390int; + r = -EINVAL; + if (kvm_is_ucontrol(kvm)) + break; r = -EFAULT; if (copy_from_user(&s390int, argp, sizeof(s390int))) break; @@ -5456,6 +5459,8 @@ long kvm_arch_vcpu_unlocked_ioctl(struct file *filp, unsigned int ioctl, struct kvm_s390_interrupt s390int; struct kvm_s390_irq s390irq = {}; + if (kvm_is_ucontrol(vcpu->kvm)) + return -EINVAL; if (copy_from_user(&s390int, argp, sizeof(s390int))) return -EFAULT; if (s390int_to_s390irq(&s390int, &s390irq)) -- cgit v1.2.3 From d699986f11bf854bddecd6b1bfdf53e05ef945d6 Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Mon, 3 Aug 2026 14:40:33 +0200 Subject: KVM: s390: Fix leaking of PGM_ADDRESSING to userspace If kvm_s390_set_cmma_bits() is asked to set CMMA values outside of a memslot, PGM_ADDRESSING (5) is returned, instead of a negative error value. Same issue with kvm_s390_{g,s}et_skeys(), kvm_s390_keyop(), and dat_reset_reference_bit(). Fix by returning -EFAULT whenever the return value would be > 0, which is consistent with the behaviour before the gmap rewrite. Fixes: e38c884df921 ("KVM: s390: Switch to new gmap") Signed-off-by: Claudio Imbrenda Message-ID: <20260803124040.126471-7-imbrenda@linux.ibm.com> --- arch/s390/kvm/dat.c | 16 ++++++++++------ arch/s390/kvm/dat.h | 2 +- arch/s390/kvm/kvm-s390.c | 16 ++++++++-------- arch/s390/kvm/priv.c | 5 +++-- 4 files changed, 22 insertions(+), 17 deletions(-) (limited to 'arch') diff --git a/arch/s390/kvm/dat.c b/arch/s390/kvm/dat.c index ed4259d17629..171b61959908 100644 --- a/arch/s390/kvm/dat.c +++ b/arch/s390/kvm/dat.c @@ -755,13 +755,15 @@ int dat_cond_set_storage_key(struct kvm_s390_mmu_cache *mmc, union asce asce, gf return rc; } -int dat_reset_reference_bit(union asce asce, gfn_t gfn) +int dat_reset_reference_bit(union asce asce, gfn_t gfn, union skey *skey) { union pgste pgste, old; union crste *crstep; union pte *ptep; int rc; + skey->skey = 0; + rc = dat_entry_walk(NULL, gfn, asce, DAT_WALK_ANY, TABLE_TYPE_PAGE_TABLE, &crstep, &ptep); if (rc) return rc; @@ -771,21 +773,23 @@ int dat_reset_reference_bit(union asce asce, gfn_t gfn) if (!crste.h.fc || !crste.s.fc1.pr) return 0; - return page_reset_referenced(large_crste_to_phys(*crstep, gfn)); + skey->skey = page_reset_referenced(large_crste_to_phys(*crstep, gfn)) << 1; + return 0; } old = pgste_get_lock(ptep); pgste = old; if (!ptep->h.i) { - rc = page_reset_referenced(pte_origin(*ptep)); - pgste.hr = rc >> 1; + skey->skey = page_reset_referenced(pte_origin(*ptep)) << 1; + pgste.hr = skey->r; } - rc |= (pgste.gr << 1) | pgste.gc; + skey->r |= pgste.gr; + skey->c |= pgste.gc; pgste.gr = 0; dat_update_ptep_sd(old, pgste, ptep); pgste_set_unlock(ptep, pgste); - return rc; + return 0; } static long dat_reset_skeys_pte(union pte *ptep, gfn_t gfn, gfn_t next, struct dat_walk *walk) diff --git a/arch/s390/kvm/dat.h b/arch/s390/kvm/dat.h index fad605305e05..141ee7b9f019 100644 --- a/arch/s390/kvm/dat.h +++ b/arch/s390/kvm/dat.h @@ -537,7 +537,7 @@ int dat_set_storage_key(struct kvm_s390_mmu_cache *mc, union asce asce, gfn_t gf union skey skey, bool nq); int dat_cond_set_storage_key(struct kvm_s390_mmu_cache *mmc, union asce asce, gfn_t gfn, union skey skey, union skey *oldkey, bool nq, bool mr, bool mc); -int dat_reset_reference_bit(union asce asce, gfn_t gfn); +int dat_reset_reference_bit(union asce asce, gfn_t gfn, union skey *skey); long dat_reset_skeys(union asce asce, gfn_t start); unsigned long dat_get_ptval(struct page_table *table, struct ptval_param param); diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 21574f57be72..e162efaa35b8 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -571,7 +571,7 @@ static int kvm_s390_keyop(struct kvm_s390_mmu_cache *mc, struct kvm *kvm, int op switch (op) { case KVM_S390_KEYOP_SSKE: r = dat_cond_set_storage_key(mc, asce, gfn, skey, &skey, 0, 0, 0); - if (r >= 0) + if (r == 0 || r == 1) return skey.skey; break; case KVM_S390_KEYOP_ISKE: @@ -580,14 +580,14 @@ static int kvm_s390_keyop(struct kvm_s390_mmu_cache *mc, struct kvm *kvm, int op return skey.skey; break; case KVM_S390_KEYOP_RRBE: - r = dat_reset_reference_bit(asce, gfn); - if (r > 0) - return r << 1; + r = dat_reset_reference_bit(asce, gfn, &skey); + if (!r) + return skey.skey; break; default: return -EINVAL; } - return r; + return r > 0 ? -EFAULT : r; } /* Section: device related */ @@ -2214,7 +2214,7 @@ static int kvm_s390_get_skeys(struct kvm *kvm, struct kvm_s390_skeys *args) } kvfree(keys); - return r; + return r <= 0 ? r : -EFAULT; } static int kvm_s390_set_skeys(struct kvm *kvm, struct kvm_s390_skeys *args) @@ -2276,7 +2276,7 @@ static int kvm_s390_set_skeys(struct kvm *kvm, struct kvm_s390_skeys *args) kvm_s390_free_mmu_cache(mc); out: kvfree(keys); - return r; + return r <= 0 ? r : -EFAULT; } /* @@ -2386,7 +2386,7 @@ static int kvm_s390_set_cmma_bits(struct kvm *kvm, set_bit(GMAP_FLAG_USES_CMM, &kvm->arch.gmap->flags); - return r; + return r <= 0 ? r : -EFAULT; } /** diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c index ad0ddc433a73..ea5a99537346 100644 --- a/arch/s390/kvm/priv.c +++ b/arch/s390/kvm/priv.c @@ -289,6 +289,7 @@ static int handle_iske(struct kvm_vcpu *vcpu) static int handle_rrbe(struct kvm_vcpu *vcpu) { unsigned long gaddr; + union skey skey; int reg1, reg2; int rc; @@ -307,12 +308,12 @@ static int handle_rrbe(struct kvm_vcpu *vcpu) gaddr = kvm_s390_logical_to_effective(vcpu, gaddr); gaddr = kvm_s390_real_to_abs(vcpu, gaddr); scoped_guard(read_lock, &vcpu->kvm->mmu_lock) - rc = dat_reset_reference_bit(vcpu->arch.gmap->asce, gpa_to_gfn(gaddr)); + rc = dat_reset_reference_bit(vcpu->arch.gmap->asce, gpa_to_gfn(gaddr), &skey); if (rc > 0) return kvm_s390_inject_program_int(vcpu, rc); if (rc < 0) return rc; - kvm_s390_set_psw_cc(vcpu, rc); + kvm_s390_set_psw_cc(vcpu, (skey.skey >> 1) & 3); return 0; } -- cgit v1.2.3 From 4db7207052874f13dec1e9be384cca279c6693e8 Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Mon, 3 Aug 2026 14:40:34 +0200 Subject: KVM: s390: Fix race in __do_essa() An unlikely race between __do_essa() and kvm_s390_vm_start_migration(), kvm_s390_vm_stop_migration(), or dat_get_cmma() was possible. Fix by locking kvm->slots_arch_lock. Since this is not a hot path, the overhead of an additional mutex is negligible. Fixes: e38c884df921 ("KVM: s390: Switch to new gmap") Signed-off-by: Claudio Imbrenda Message-ID: <20260803124040.126471-8-imbrenda@linux.ibm.com> --- arch/s390/kvm/kvm-s390.c | 20 ++++++++++---------- arch/s390/kvm/priv.c | 5 +++-- 2 files changed, 13 insertions(+), 12 deletions(-) (limited to 'arch') diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index e162efaa35b8..e5c5e9f61cb2 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -1219,8 +1219,8 @@ static void kvm_s390_sync_request_broadcast(struct kvm *kvm, int req) /* * Must be called with kvm->srcu held to avoid races on memslots, and with - * kvm->slots_lock to avoid races with ourselves, kvm_s390_vm_stop_migration(), - * and kvm_s390_get_cmma_bits(). + * kvm->slots_arch_lock to avoid races with ourselves, + * kvm_s390_vm_stop_migration(), and kvm_s390_get_cmma_bits(). */ static int kvm_s390_vm_start_migration(struct kvm *kvm) { @@ -1265,7 +1265,7 @@ static int kvm_s390_vm_start_migration(struct kvm *kvm) } /* - * Must be called with kvm->slots_lock to avoid races with ourselves, + * Must be called with kvm->slots_arch_lock to avoid races with ourselves, * kvm_s390_vm_start_migration() and kvm_s390_get_cmma_bits(). */ static int kvm_s390_vm_stop_migration(struct kvm *kvm) @@ -1300,7 +1300,9 @@ static int kvm_s390_vm_set_migration(struct kvm *kvm, { int res = -ENXIO; - mutex_lock(&kvm->slots_lock); + guard(srcu)(&kvm->srcu); + guard(mutex)(&kvm->slots_arch_lock); + switch (attr->attr) { case KVM_S390_VM_MIGRATION_START: res = kvm_s390_vm_start_migration(kvm); @@ -1311,7 +1313,6 @@ static int kvm_s390_vm_set_migration(struct kvm *kvm, default: break; } - mutex_unlock(&kvm->slots_lock); return res; } @@ -3001,9 +3002,8 @@ int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) r = -EFAULT; if (copy_from_user(&args, argp, sizeof(args))) break; - mutex_lock(&kvm->slots_lock); - r = kvm_s390_get_cmma_bits(kvm, &args); - mutex_unlock(&kvm->slots_lock); + scoped_guard(mutex, &kvm->slots_arch_lock) + r = kvm_s390_get_cmma_bits(kvm, &args); if (!r) { r = copy_to_user(argp, &args, sizeof(args)); if (r) @@ -3017,9 +3017,9 @@ int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) r = -EFAULT; if (copy_from_user(&args, argp, sizeof(args))) break; - mutex_lock(&kvm->slots_lock); + mutex_lock(&kvm->slots_arch_lock); r = kvm_s390_set_cmma_bits(kvm, &args); - mutex_unlock(&kvm->slots_lock); + mutex_unlock(&kvm->slots_arch_lock); break; } case KVM_S390_PV_COMMAND: { diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c index ea5a99537346..b1ba24c346ef 100644 --- a/arch/s390/kvm/priv.c +++ b/arch/s390/kvm/priv.c @@ -1261,8 +1261,9 @@ static int handle_essa(struct kvm_vcpu *vcpu) /* Retry the ESSA instruction */ kvm_s390_retry_instr(vcpu); } else { - scoped_guard(read_lock, &vcpu->kvm->mmu_lock) - i = __do_essa(vcpu, orc); + scoped_guard(mutex, &vcpu->kvm->slots_arch_lock) + scoped_guard(read_lock, &vcpu->kvm->mmu_lock) + i = __do_essa(vcpu, orc); if (i < 0) return i; /* Account for the possible extra cbrl entry */ -- cgit v1.2.3 From ec215346270512db60478e45e8dff2de950225aa Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Mon, 3 Aug 2026 14:40:35 +0200 Subject: KVM: s390: cmma: Fix dirty tracking when removing memslot When a memslot is removed, all ptes that mapped the slot are cleared or even deallocated. If this happens while the system is in migration mode, and if cmma-dirty pages are removed, the cmma-dirty counter will not reflect reality. Fix by appropriately decrementing the cmma-dirty counter when removing a memslot. Opportunistically improve kvm_arch_commit_memory_region() to use __free() for the struct kvm_s390_mmu_cache. Fixes: e38c884df921 ("KVM: s390: Switch to new gmap") Signed-off-by: Claudio Imbrenda Message-ID: <20260803124040.126471-9-imbrenda@linux.ibm.com> --- arch/s390/kvm/dat.c | 7 ++++++- arch/s390/kvm/kvm-s390.c | 25 +++++++++++++++++++++++-- 2 files changed, 29 insertions(+), 3 deletions(-) (limited to 'arch') diff --git a/arch/s390/kvm/dat.c b/arch/s390/kvm/dat.c index 171b61959908..3f2d6e8902d7 100644 --- a/arch/s390/kvm/dat.c +++ b/arch/s390/kvm/dat.c @@ -850,6 +850,7 @@ static long _dat_slot_pte(union pte *ptep, gfn_t gfn, gfn_t next, struct dat_wal struct slot_priv *p = walk->priv; union crste dummy = { .val = p->token }; union pte new_pte, pte = READ_ONCE(*ptep); + union pgste pgste; new_pte = _PTE_TOK(dummy.tok.type, dummy.tok.par); @@ -857,7 +858,11 @@ static long _dat_slot_pte(union pte *ptep, gfn_t gfn, gfn_t next, struct dat_wal if (pte.val == new_pte.val) return 0; - dat_ptep_xchg(ptep, new_pte, gfn, walk->asce, false); + pgste = pgste_get_lock(ptep); + pgste = __dat_ptep_xchg(ptep, pgste, new_pte, gfn, walk->asce, false); + pgste.cmma_d = 0; + pgste_set_unlock(ptep, pgste); + return 0; } diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index e5c5e9f61cb2..ba811f0673d1 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -5812,14 +5812,30 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, return 0; } +static long cmma_d_count_pte(union pte *ptep, gfn_t gfn, gfn_t next, struct dat_walk *walk) +{ + union pgste pgste; + + pgste = pgste_get_lock(ptep); + if (pgste.cmma_d) { + pgste.cmma_d = 0; + atomic64_dec(walk->priv); + } + pgste_set_unlock(ptep, pgste); + return 0; +} + void kvm_arch_commit_memory_region(struct kvm *kvm, struct kvm_memory_slot *old, const struct kvm_memory_slot *new, enum kvm_mr_change change) { - struct kvm_s390_mmu_cache *mc = NULL; + const struct dat_walk_ops ops = { .pte_entry = cmma_d_count_pte, }; + struct kvm_s390_mmu_cache *mc __free(kvm_s390_mmu_cache) = NULL; int rc = 0; + guard(mutex)(&kvm->slots_arch_lock); + if (change == KVM_MR_FLAGS_ONLY) return; @@ -5830,6 +5846,12 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, } scoped_guard(write_lock, &kvm->mmu_lock) { + if (kvm->arch.migration_mode && kvm->arch.use_cmma && old) { + _dat_walk_gfn_range(old->base_gfn, old->base_gfn + old->npages, + kvm->arch.gmap->asce, &ops, DAT_WALK_IGN_HOLES, + &kvm->arch.cmma_dirty_pages); + } + switch (change) { case KVM_MR_DELETE: rc = dat_delete_slot(mc, kvm->arch.gmap->asce, old->base_gfn, old->npages); @@ -5851,7 +5873,6 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, out: if (rc) pr_warn("failed to commit memory region\n"); - kvm_s390_free_mmu_cache(mc); return; } -- cgit v1.2.3 From dab62d218754e00a22aff45d2b0116c5ee30cbd2 Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Mon, 3 Aug 2026 14:40:36 +0200 Subject: KVM: s390: ucontrol: Add missing locking around gmap_remove_child() gmap_remove_child() needs to be called while holding the children_lock of the parent gmap. This was not the case in the error handling path of kvm_arch_vcpu_create() for UCONTROL guests. Fix by adding the missing lock. Fixes: e38c884df921 ("KVM: s390: Switch to new gmap") Reviewed-by: Steffen Eiden Signed-off-by: Claudio Imbrenda Message-ID: <20260803124040.126471-10-imbrenda@linux.ibm.com> --- arch/s390/kvm/kvm-s390.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch') diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index ba811f0673d1..2741ca323ede 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -3875,7 +3875,9 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) out_ucontrol_uninit: if (kvm_is_ucontrol(vcpu->kvm)) { + spin_lock(&vcpu->kvm->arch.gmap->children_lock); gmap_remove_child(vcpu->arch.gmap); + spin_unlock(&vcpu->kvm->arch.gmap->children_lock); vcpu->arch.gmap = gmap_put(vcpu->arch.gmap); } out_free_sie_block: -- cgit v1.2.3 From e4d678900a1ae66112812fe4d2aff16044ca37f2 Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Mon, 3 Aug 2026 14:40:37 +0200 Subject: KVM: s390: Free the mmu cache when kvm_arch_vcpu_create() fails The mmu cache is the first thing that is allocated in kvm_arch_vcpu_create(), but in case of failure it was not freed. Fix by freeing the mmu cache in case of failure. Refactor kvm_arch_vcpu_create() to use scope-based cleanup instead of gotos. Fixes: e38c884df921 ("KVM: s390: Switch to new gmap") Signed-off-by: Claudio Imbrenda Message-ID: <20260803124040.126471-11-imbrenda@linux.ibm.com> --- arch/s390/kvm/kvm-s390.c | 40 ++++++++++++++++++---------------------- 1 file changed, 18 insertions(+), 22 deletions(-) (limited to 'arch') diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 2741ca323ede..9b8a35e7dc82 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -3800,21 +3800,21 @@ int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id) return 0; } +DEFINE_FREE(sie_page, struct sie_page *, if (_T) free_page((unsigned long)(_T))) + int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) { - struct sie_page *sie_page; + struct kvm_s390_mmu_cache *mc __free(kvm_s390_mmu_cache) = NULL; + struct sie_page *sie_page __free(sie_page) = NULL; int rc; BUILD_BUG_ON(sizeof(struct sie_page) != 4096); - vcpu->arch.mc = kvm_s390_new_mmu_cache(); - if (!vcpu->arch.mc) + mc = kvm_s390_new_mmu_cache(); + if (!mc) return -ENOMEM; sie_page = (struct sie_page *) get_zeroed_page(GFP_KERNEL_ACCOUNT); - if (!sie_page) { - kvm_s390_free_mmu_cache(vcpu->arch.mc); - vcpu->arch.mc = NULL; + if (!sie_page) return -ENOMEM; - } vcpu->arch.sie_block = &sie_page->sie_block; vcpu->arch.sie_block->itdba = virt_to_phys(&sie_page->itdb); @@ -3856,10 +3856,9 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) vcpu->run->kvm_valid_regs |= KVM_SYNC_FPRS; if (kvm_is_ucontrol(vcpu->kvm)) { - rc = -ENOMEM; vcpu->arch.gmap = gmap_new_child(vcpu->kvm->arch.gmap, -1UL); if (!vcpu->arch.gmap) - goto out_free_sie_block; + return -ENOMEM; } VM_EVENT(vcpu->kvm, 3, "create cpu %d at 0x%p, sie block at 0x%p", @@ -3867,22 +3866,19 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) trace_kvm_s390_create_vcpu(vcpu->vcpu_id, vcpu, vcpu->arch.sie_block); rc = kvm_s390_vcpu_setup(vcpu); - if (rc) - goto out_ucontrol_uninit; + if (rc) { + if (kvm_is_ucontrol(vcpu->kvm)) { + scoped_guard(spinlock, &vcpu->kvm->arch.gmap->children_lock) + gmap_remove_child(vcpu->arch.gmap); + vcpu->arch.gmap = gmap_put(vcpu->arch.gmap); + } + return rc; + } + vcpu->arch.mc = no_free_ptr(mc); + sie_page = NULL; kvm_s390_update_topology_change_report(vcpu->kvm, 1); return 0; - -out_ucontrol_uninit: - if (kvm_is_ucontrol(vcpu->kvm)) { - spin_lock(&vcpu->kvm->arch.gmap->children_lock); - gmap_remove_child(vcpu->arch.gmap); - spin_unlock(&vcpu->kvm->arch.gmap->children_lock); - vcpu->arch.gmap = gmap_put(vcpu->arch.gmap); - } -out_free_sie_block: - free_page((unsigned long)(vcpu->arch.sie_block)); - return rc; } int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu) -- cgit v1.2.3 From 216c5289dd66d9cde6b42cbe68ee8dec5669678a Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Mon, 3 Aug 2026 14:40:38 +0200 Subject: KVM: s390: Return -EINTR if a signal is pending while faulting-in If a fatal signal is pending while trying to fault-in a page, return -EINTR instead of -EAGAIN. Also fix unpack_one() to handle -EINTR properly. Fixes: e907ae530133 ("KVM: s390: Add helper functions for fault handling") Signed-off-by: Claudio Imbrenda Message-ID: <20260803124040.126471-12-imbrenda@linux.ibm.com> --- arch/s390/kvm/faultin.c | 6 +++--- arch/s390/kvm/pv.c | 2 +- 2 files changed, 4 insertions(+), 4 deletions(-) (limited to 'arch') diff --git a/arch/s390/kvm/faultin.c b/arch/s390/kvm/faultin.c index fee80047bd94..3cc45f7f5b2d 100644 --- a/arch/s390/kvm/faultin.c +++ b/arch/s390/kvm/faultin.c @@ -91,9 +91,9 @@ int kvm_s390_faultin_gfn(struct kvm_vcpu *vcpu, struct kvm *kvm, struct guest_fa /* Access outside memory, addressing exception. */ if (is_noslot_pfn(f->pfn)) return PGM_ADDRESSING; - /* Signal pending: try again. */ - if (f->pfn == KVM_PFN_ERR_SIGPENDING) - return -EAGAIN; + /* Fatal signal pending: bail out. */ + if (is_sigpending_pfn(f->pfn)) + return -EINTR; /* Check if it's read-only memory; don't try to actually handle that case. */ if (f->pfn == KVM_PFN_ERR_RO_FAULT) return -EOPNOTSUPP; diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c index 1beacc841ca8..dc204b521052 100644 --- a/arch/s390/kvm/pv.c +++ b/arch/s390/kvm/pv.c @@ -809,7 +809,7 @@ static int unpack_one(struct kvm *kvm, unsigned long addr, u64 tweak, return -EAGAIN; } - if (ret && ret != -EAGAIN) + if (ret && ret != -EAGAIN && ret != -EINTR) KVM_UV_EVENT(kvm, 3, "PROTVIRT VM UNPACK: failed addr %llx with rc %x rrc %x", uvcb.gaddr, *rc, *rrc); return ret; -- cgit v1.2.3 From 9187a9186d0ac7b260b07917aabc672a80d37c3c Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Mon, 3 Aug 2026 14:40:39 +0200 Subject: KVM: s390: Fix ordering when adding to SCA When adding a new vCPU to the SCA area, the validity bit in the MCN was set before the pointer to the state description, potentially allowing for a race. Fix by setting the pointer before setting the bit. Fixes: 14542a0a54c5 ("KVM: S390: Remove sca_lock") Reviewed-by: Steffen Eiden Reviewed-by: Janosch Frank Signed-off-by: Claudio Imbrenda Message-ID: <20260803124040.126471-13-imbrenda@linux.ibm.com> --- arch/s390/kvm/kvm-s390.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 9b8a35e7dc82..518a69c55e85 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -3485,8 +3485,8 @@ static void sca_add_vcpu(struct kvm_vcpu *vcpu) if (!kvm_s390_use_sca_entries()) return; + WRITE_ONCE(sca->cpu[vcpu->vcpu_id].sda, virt_to_phys(vcpu->arch.sie_block)); set_bit_inv(vcpu->vcpu_id, (unsigned long *)sca->mcn); - sca->cpu[vcpu->vcpu_id].sda = virt_to_phys(vcpu->arch.sie_block); } static int sca_can_add_vcpu(struct kvm *kvm, unsigned int id) -- cgit v1.2.3 From feadc5e84dcb53422a437556c35af9efd9826fd5 Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Mon, 3 Aug 2026 14:40:40 +0200 Subject: KVM: s390: Fix cleanup in kvm_s390_pv_create_cpu() If creating a protected vCPU in kvm_s390_pv_create_cpu() fails, kvm_s390_pv_destroy_cpu() was called, which checks whether the vCPU has a PV handle and exits doing nothing otherwise. At that point, due to not having created the protected vCPU, the PV handle will not be set, and kvm_s390_pv_destroy_cpu() will do nothing, thus leaking the allocated memory. Fix by factoring out the code to free and reset a PV vCPU; call it from kvm_s390_pv_destroy_cpu() and kvm_s390_pv_create_cpu(). Opportunistically fix the return value of kvm_s390_pv_destroy_cpu() in case of errors: return -EIO instead if EIO. Fixes: d4074324b07a ("KVM: s390: pv: avoid double free of sida page") Reviewed-by: Steffen Eiden Reviewed-by: Janosch Frank Signed-off-by: Claudio Imbrenda Message-ID: <20260803124040.126471-14-imbrenda@linux.ibm.com> --- arch/s390/kvm/pv.c | 41 +++++++++++++++++++++-------------------- 1 file changed, 21 insertions(+), 20 deletions(-) (limited to 'arch') diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c index dc204b521052..b02e0159d3cd 100644 --- a/arch/s390/kvm/pv.c +++ b/arch/s390/kvm/pv.c @@ -244,6 +244,24 @@ static void kvm_s390_clear_pv_state(struct kvm *kvm) kvm->arch.pv.stor_var = NULL; } +static void kvm_s390_pv_dispose_cpu(struct kvm_vcpu *vcpu, bool free_stor_base) +{ + if (free_stor_base) + free_pages(vcpu->arch.pv.stor_base, get_order(uv_info.guest_cpu_stor_len)); + free_page((unsigned long)sida_addr(vcpu->arch.sie_block)); + vcpu->arch.sie_block->pv_handle_cpu = 0; + vcpu->arch.sie_block->pv_handle_config = 0; + memset(&vcpu->arch.pv, 0, sizeof(vcpu->arch.pv)); + vcpu->arch.sie_block->sdf = 0; + /* + * The sidad field (for sdf == 2) is now the gbea field (for sdf == 0). + * Use the reset value of gbea to avoid leaking the kernel pointer of + * the just freed sida. + */ + vcpu->arch.sie_block->gbea = 1; + kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu); +} + int kvm_s390_pv_destroy_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc) { int cc; @@ -258,24 +276,9 @@ int kvm_s390_pv_destroy_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc) WARN_ONCE(cc, "protvirt destroy cpu failed rc %x rrc %x", *rc, *rrc); /* Intended memory leak for something that should never happen. */ - if (!cc) - free_pages(vcpu->arch.pv.stor_base, - get_order(uv_info.guest_cpu_stor_len)); - - free_page((unsigned long)sida_addr(vcpu->arch.sie_block)); - vcpu->arch.sie_block->pv_handle_cpu = 0; - vcpu->arch.sie_block->pv_handle_config = 0; - memset(&vcpu->arch.pv, 0, sizeof(vcpu->arch.pv)); - vcpu->arch.sie_block->sdf = 0; - /* - * The sidad field (for sdf == 2) is now the gbea field (for sdf == 0). - * Use the reset value of gbea to avoid leaking the kernel pointer of - * the just freed sida. - */ - vcpu->arch.sie_block->gbea = 1; - kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu); + kvm_s390_pv_dispose_cpu(vcpu, !cc); - return cc ? EIO : 0; + return cc ? -EIO : 0; } int kvm_s390_pv_create_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc) @@ -319,9 +322,7 @@ int kvm_s390_pv_create_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc) uvcb.header.rrc); if (cc) { - u16 dummy; - - kvm_s390_pv_destroy_cpu(vcpu, &dummy, &dummy); + kvm_s390_pv_dispose_cpu(vcpu, true); return -EIO; } -- cgit v1.2.3 From a213dfaa2596c1c0dc4dae91c14fbfa499c03223 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Mon, 3 Aug 2026 02:47:40 -0700 Subject: x86/mce: Set up the polling timer before CMCI discovery I hit the following on one of my machines: mce: CPU0 BANK15 CMCI inherited storm ------------[ cut here ]------------ ODEBUG: assert_init not available (active state 0) object: (____ptrval____) object type: timer_list hint: 0x0 WARNING: lib/debugobjects.c:632 at debug_object_assert_init+0x178/0x230, CPU#0: swapper/0/0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 7.2.0-rc5 #3 PREEMPTLAZY RIP: 0010:debug_object_assert_init+0x18f/0x230 Call Trace: __mod_timer mce_timer_kick cmci_discover intel_init_cmci mce_intel_feature_init mcheck_cpu_init identify_cpu identify_boot_cpu arch_cpu_finalize_init start_kernel A second splat follows right after, from timer_setup() finding that same timer already queued: ODEBUG: init active (active state 0) object: (____ptrval____) object type: timer_list hint: stub_timer+0x0/0x10 This is happening because CMCI storm detection is trying to modify the timer before latter was properly set up. Set up the timer first. __mcheck_cpu_setup_timer() only calls timer_setup(), and depends on neither the generic nor the vendor init. [ bp: Massage commit message. ] Fixes: 1f68ce2a0272 ("x86/mce: Handle Intel threshold interrupt storms") Signed-off-by: Breno Leitao Signed-off-by: Borislav Petkov (AMD) Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260803-mce_timer_init-v1-1-9539db424330@debian.org --- arch/x86/kernel/cpu/mce/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 9bba1e2f03af..cfb74be19994 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -2266,10 +2266,10 @@ void mcheck_cpu_init(struct cpuinfo_x86 *c) mca_cfg.initialized = 1; + __mcheck_cpu_setup_timer(); __mcheck_cpu_init_generic(); __mcheck_cpu_init_vendor(c); __mcheck_cpu_init_prepare_banks(); - __mcheck_cpu_setup_timer(); cr4_set_bits(X86_CR4_MCE); } -- cgit v1.2.3 From 9d3277b2c07ccc9508d648098b3bbb46c61b7f3c Mon Sep 17 00:00:00 2001 From: "Lorenzo Stoakes (ARM)" Date: Thu, 23 Jul 2026 16:16:35 +0100 Subject: arm64: remove redundant concurrent ptdump UAF mitigation This partially reverts commit fa93b45fd397 ("arm64: Enable vmalloc-huge with ptdump"), retaining vmalloc-huge support but eliminating the now redundant mitigation against a race between huge vmap page table freeing and ptdump, as this issue has now been fixed at core. We also simultaneously remove the arm64 if-deffery when acquiring the mmap read lock upon vmap huge page table promotion as it is no longer required. Note that this patch relies on the preceding vmalloc patch, and should not be backported alone. Link: https://lore.kernel.org/20260723-series-vmap-race-fix-v6-5-8cc77dcc0018@kernel.org Fixes: fa93b45fd397 ("arm64: Enable vmalloc-huge with ptdump") Signed-off-by: Lorenzo Stoakes (ARM) Reviewed-by: Dev Jain Acked-by: Mike Rapoport (Microsoft) Acked-by: Kiryl Shutsemau (Meta) Acked-by: Will Deacon Reviewed-by: David Hildenbrand (Arm) Cc: Andy Lutomirski Cc: "Borah, Chaitanya Kumar" Cc: "Borislav Petkov (AMD)" Cc: Catalin Marinas Cc: Dave Hansen Cc: David Carlier Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Liam R. Howlett Cc: Michal Hocko Cc: Peter Zijlstra Cc: Ryan Roberts Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Toshi Kani Cc: "Uladzislau Rezki (Sony)" Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton --- arch/arm64/include/asm/ptdump.h | 2 -- arch/arm64/mm/mmu.c | 43 ++++------------------------------------- arch/arm64/mm/ptdump.c | 11 ++--------- 3 files changed, 6 insertions(+), 50 deletions(-) (limited to 'arch') diff --git a/arch/arm64/include/asm/ptdump.h b/arch/arm64/include/asm/ptdump.h index 5b374a6ab34a..50a195eda8ed 100644 --- a/arch/arm64/include/asm/ptdump.h +++ b/arch/arm64/include/asm/ptdump.h @@ -7,8 +7,6 @@ #include -DECLARE_STATIC_KEY_FALSE(arm64_ptdump_lock_key); - #ifdef CONFIG_PTDUMP #include diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 18a8b0d3714e..d4de88770ecf 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -49,8 +49,6 @@ #define NO_CONT_MAPPINGS BIT(1) #define NO_EXEC_MAPPINGS BIT(2) /* assumes FEAT_HPDS is not used */ -DEFINE_STATIC_KEY_FALSE(arm64_ptdump_lock_key); - u64 kimage_voffset __ro_after_init; EXPORT_SYMBOL(kimage_voffset); @@ -1864,8 +1862,7 @@ int pmd_clear_huge(pmd_t *pmdp) return 1; } -static int __pmd_free_pte_page(pmd_t *pmdp, unsigned long addr, - bool acquire_mmap_lock) +int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) { pte_t *table; pmd_t pmd; @@ -1877,25 +1874,13 @@ static int __pmd_free_pte_page(pmd_t *pmdp, unsigned long addr, return 1; } - /* See comment in pud_free_pmd_page for static key logic */ table = pte_offset_kernel(pmdp, addr); pmd_clear(pmdp); __flush_tlb_kernel_pgtable(addr); - if (static_branch_unlikely(&arm64_ptdump_lock_key) && acquire_mmap_lock) { - mmap_read_lock(&init_mm); - mmap_read_unlock(&init_mm); - } - pte_free_kernel(NULL, table); return 1; } -int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) -{ - /* If ptdump is walking the pagetables, acquire init_mm.mmap_lock */ - return __pmd_free_pte_page(pmdp, addr, /* acquire_mmap_lock = */ true); -} - int pud_free_pmd_page(pud_t *pudp, unsigned long addr) { pmd_t *table; @@ -1911,36 +1896,16 @@ int pud_free_pmd_page(pud_t *pudp, unsigned long addr) } table = pmd_offset(pudp, addr); - - /* - * Our objective is to prevent ptdump from reading a PMD table which has - * been freed. In this race, if pud_free_pmd_page observes the key on - * (which got flipped by ptdump) then the mmap lock sequence here will, - * as a result of the mmap write lock/unlock sequence in ptdump, give - * us the correct synchronization. If not, this means that ptdump has - * yet not started walking the pagetables - the sequence of barriers - * issued by __flush_tlb_kernel_pgtable() guarantees that ptdump will - * observe an empty PUD. - */ - pud_clear(pudp); - __flush_tlb_kernel_pgtable(addr); - if (static_branch_unlikely(&arm64_ptdump_lock_key)) { - mmap_read_lock(&init_mm); - mmap_read_unlock(&init_mm); - } - pmdp = table; next = addr; end = addr + PUD_SIZE; do { if (pmd_present(pmdp_get(pmdp))) - /* - * PMD has been isolated, so ptdump won't see it. No - * need to acquire init_mm.mmap_lock. - */ - __pmd_free_pte_page(pmdp, next, /* acquire_mmap_lock = */ false); + pmd_free_pte_page(pmdp, next); } while (pmdp++, next += PMD_SIZE, next != end); + pud_clear(pudp); + __flush_tlb_kernel_pgtable(addr); pmd_free(NULL, table); return 1; } diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c index 1c20144700d7..5a76c59b5ada 100644 --- a/arch/arm64/mm/ptdump.c +++ b/arch/arm64/mm/ptdump.c @@ -283,13 +283,6 @@ void note_page_flush(struct ptdump_state *pt_st) note_page(pt_st, 0, -1, pte_val(pte_zero)); } -static void arm64_ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm) -{ - static_branch_inc(&arm64_ptdump_lock_key); - ptdump_walk_pgd(st, mm, NULL); - static_branch_dec(&arm64_ptdump_lock_key); -} - void ptdump_walk(struct seq_file *s, struct ptdump_info *info) { unsigned long end = ~0UL; @@ -318,7 +311,7 @@ void ptdump_walk(struct seq_file *s, struct ptdump_info *info) } }; - arm64_ptdump_walk_pgd(&st.ptdump, info->mm); + ptdump_walk_pgd(&st.ptdump, info->mm, NULL); } static void __init ptdump_initialize(void) @@ -360,7 +353,7 @@ bool ptdump_check_wx(void) } }; - arm64_ptdump_walk_pgd(&st.ptdump, &init_mm); + ptdump_walk_pgd(&st.ptdump, &init_mm, NULL); if (st.wx_pages || st.uxn_pages) { pr_warn("Checked W+X mappings: FAILED, %lu W+X pages found, %lu non-UXN pages found\n", -- cgit v1.2.3 From c2689266e5f70ecc960e64d40516518c038ae34e Mon Sep 17 00:00:00 2001 From: Ramin Moussavi Date: Mon, 27 Jul 2026 23:58:23 +0200 Subject: microblaze: restore the page alignment of swapper_pg_dir microblaze handles TLB misses in software, and the handler builds the address of the L1 entry by ORing the index into the page directory base instead of adding it (hw_exception_handler.S): bsrli r5, r3, PGDIR_SHIFT - 2 andi r5, r5, PAGE_SIZE - 4 /* Assume pgdir aligned on 4K boundary, no need for "andi r4,r4,0xfffff003" */ or r4, r4, r5 lwi r4, r4, 0 /* Get L1 entry */ The index is masked to the low 12 bits, so the OR only works if those bits of the base are zero -- which is exactly the assumption the comment states and the reason the masking of the base can be skipped. swapper_pg_dir had no alignment directive of its own. It was aligned because it followed empty_zero_page in head.S, and that one carried the .align 12: .section .data .global empty_zero_page .align 12 empty_zero_page: .space PAGE_SIZE .global swapper_pg_dir swapper_pg_dir: .space PAGE_SIZE Commit 6215d9f4470f ("arch, mm: consolidate empty_zero_page") removed empty_zero_page from head.S, and with it the .align 12 that -- despite sitting next to empty_zero_page -- was what page aligned swapper_pg_dir. Since then swapper_pg_dir lands wherever .data happens to put it, its low bits are no longer zero, and every kernel TLB miss ORs the index into a base with a nonzero offset. The resulting L1 lookups read the wrong words, no valid translation is ever installed, and the kernel spins in exceptions long before it can print anything. On qemu-system-microblazeel (petalogix-s3adsp1800) the console stays completely silent at 100% CPU; there is no oops and no guest error reported by qemu, which makes this awkward to diagnose. Give swapper_pg_dir the alignment it requires, rather than relying on a neighbour to provide it. microblaze has no noMMU variant left in mainline -- CONFIG_MMU is def_bool y and mmu_defconfig is the only defconfig -- so this is not a corner case: every mainline microblaze kernel since v7.1-rc1 fails to boot, including the v7.1 release. v7.0: swapper_pg_dir = 0xc05fd000 (aligned) v7.1-rc1: swapper_pg_dir = 0xc0603140 (offset 320) v7.1-rc1 + this fix: swapper_pg_dir = 0xc0604000 (aligned) next-20260726: swapper_pg_dir = 0xc0615140 (offset 320) next-20260726 + this fix: swapper_pg_dir = 0xc0616000 (aligned) Verified on qemu-system-microblazeel (petalogix-s3adsp1800) with mmu_defconfig and microblazeel gcc 12.5.0: v7.1-rc1 and next-20260726 both print nothing at all without the fix, and both boot to userspace with it. Link: https://lore.kernel.org/20260727215823.1422701-1-ramin.moussavi@yacoub.de Fixes: 6215d9f4470f ("arch, mm: consolidate empty_zero_page") Signed-off-by: Ramin Moussavi Cc: Michal Simek Cc: Mike Rapoport Cc: Signed-off-by: Andrew Morton --- arch/microblaze/kernel/head.S | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch') diff --git a/arch/microblaze/kernel/head.S b/arch/microblaze/kernel/head.S index 808019c3b7ac..9bd3e513c89b 100644 --- a/arch/microblaze/kernel/head.S +++ b/arch/microblaze/kernel/head.S @@ -39,6 +39,8 @@ #include .section .data +/* The MMU requires a page aligned page directory. */ +.align 12 .global swapper_pg_dir swapper_pg_dir: .space PAGE_SIZE -- cgit v1.2.3 From 26505e1b5b546e2fa9a0296b951ca158460c72d8 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 23 Jul 2026 10:15:22 +0200 Subject: KVM: SVM: make svm_flush_tlb_gva do a full asid flush if NPT enabled Red Hat is seeing multiple reports of Windows memory corruptions (and consequent BSODs) with hv-tlbflush=on, on AMD processors only. The crashes, while extremely rare, happen even with a stock configuration, but with Driver Verifier enabled they can be detected after approximately 200 VM hours. In particular, Alexander Lougovski measured the following: - on AMD Turin, 15 crashes in 3300 VM hours - on AMD Milan, 2 crashes in 500 VM hours (there are fewer hours here due to the host being smaller) - on Intel Sapphire Rapids, 0 crashes in 8000 VM hours - on AMD Turin with full TLB flush (not exactly this patch but similar), no crashes in ~2 weeks of run time which should also be ~7000 VM hours For Turin, the microcode version was 0x0b002162, which (assuming this is the same issue) should not be affected by the problem listed in https://knowledge.broadcom.com/external/article/419026/bsod-on-virtual-machines-running-on-amd.html; on the other hand that problem should not apply to earlier processors. AMD has not provided any information or analysis yet, and when we asked we didn't know yet that it reproduced on Milan as well. As to the workload, Alexander threw more or less everything at the same time at the VM: - a full Windows Defender scan every 30 minutes - a disk I/O job - a loop doing repeated mmap of system files (mostly to hope that it triggers some consistency check in the Windows memory manager) - SQL Express 2022 + StressDB (1.6M rows), with the host doing queries (75% write/25% read) via sqlcmd Driver Verifier is able to detect BSODs more or less at the same time as the pages are freed. They mostly happen in the Windows Defender filter driver, but occasionally also in the networking stack (e.g., afd.sys) or elsewhere in the filesystem stack (e.g., fltmgr.sys). The flush is issued from kvm_hv_vcpu_flush_tlb(), which receives the cross-CPU requests from the Hyper-V TLB flush hypercalls via a kfifo and is invoked by the KVM_REQ_HV_TLB_FLUSH request. The mechanism is the same for both Intel and AMD, and the handler for both vendors is a simple INVVPID(ADDR)/INVLPGA instruction. Because the request is handled on the destination CPU, there is a question of what happens if the VM is migrated across physical CPUs. In that case, the INVLPGA instruction would use a stale svm->vmcb->control.asid; but if anything that might do an *unnecessary* flush (on an asid that's being used for another VM) and then pre_svm_run() would force a full TLB rebuild. So, for lack of better ideas, this patch forces a full ASID bump in svm_flush_tlb_gva(). To avoid paying the price on Intel and also to avoid unnecessary loops on AMD, the flush_tlb_gva op now returns whether it did a full flush or not; kvm_hv_vcpu_flush_tlb() takes note and exits its loops immediately. While there is an obvious performance impact, about half of the benefit from Hyper-V tlbflush is preserved (10% vs. 20% on the SQL Server workload). kvm_mmu_invalidate_addr() is the only other caller of the flush_tlb_gva op. The change would have a performance impact on every intercepted INVLPG and, for nested SVM, on every L1 INVLPGA. For INVLPGA specifically, this covers the same suspected issue but for nested hypervisors, so it is correct to apply the workaround; for INVLPG on shadow paging, instead, the impact would be stronger and, due to lack of data, for now the use of INVLPGA is left in place in svm_flush_tlb_gva(). Analyzed-by: Vitaly Kuznetsov Analyzed-by: Alexander Lougovski Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm_host.h | 2 +- arch/x86/kvm/hyperv.c | 7 ++++--- arch/x86/kvm/mmu/mmu.c | 2 +- arch/x86/kvm/svm/svm.c | 25 +++++++++++++++++++------ arch/x86/kvm/vmx/main.c | 4 ++-- arch/x86/kvm/vmx/vmx.c | 2 +- arch/x86/kvm/vmx/x86_ops.h | 2 +- 7 files changed, 29 insertions(+), 15 deletions(-) (limited to 'arch') diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 5f6c1ce9673b..6db5b5f79df9 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1858,7 +1858,7 @@ struct kvm_x86_ops { * Can potentially get non-canonical addresses through INVLPGs, which * the implementation may choose to ignore if appropriate. */ - void (*flush_tlb_gva)(struct kvm_vcpu *vcpu, gva_t addr); + void (*flush_tlb_gva)(struct kvm_vcpu *vcpu, gva_t addr, bool *full); /* * Flush any TLB entries created by the guest. Like tlb_flush_gva(), diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index fd4eb1e561f7..d8736b5dfcd3 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1974,6 +1974,7 @@ int kvm_hv_vcpu_flush_tlb(struct kvm_vcpu *vcpu) u64 entries[KVM_HV_TLB_FLUSH_FIFO_SIZE]; int i, j, count; gva_t gva; + bool full = false; if (!tdp_enabled || !hv_vcpu) return -EINVAL; @@ -1982,7 +1983,7 @@ int kvm_hv_vcpu_flush_tlb(struct kvm_vcpu *vcpu) count = kfifo_out(&tlb_flush_fifo->entries, entries, KVM_HV_TLB_FLUSH_FIFO_SIZE); - for (i = 0; i < count; i++) { + for (i = 0; i < count && !full; i++) { if (entries[i] == KVM_HV_TLB_FLUSHALL_ENTRY) goto out_flush_all; @@ -1991,11 +1992,11 @@ int kvm_hv_vcpu_flush_tlb(struct kvm_vcpu *vcpu) * pages to flush. */ gva = entries[i] & PAGE_MASK; - for (j = 0; j < (entries[i] & ~PAGE_MASK) + 1; j++) { + for (j = 0; j < (entries[i] & ~PAGE_MASK) + 1 && !full; j++) { if (is_noncanonical_invlpg_address(gva + j * PAGE_SIZE, vcpu)) continue; - kvm_x86_call(flush_tlb_gva)(vcpu, gva + j * PAGE_SIZE); + kvm_x86_call(flush_tlb_gva)(vcpu, gva + j * PAGE_SIZE, &full); } ++vcpu->stat.tlb_flush; diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 66e69d2a41b3..c9e4739b26d7 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -6652,7 +6652,7 @@ void kvm_mmu_invalidate_addr(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, if (is_noncanonical_invlpg_address(addr, vcpu)) return; - kvm_x86_call(flush_tlb_gva)(vcpu, addr); + kvm_x86_call(flush_tlb_gva)(vcpu, addr, NULL); } if (!mmu->sync_spte) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index d0971685034b..60495447f0ca 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4227,18 +4227,31 @@ static void svm_flush_tlb_all(struct kvm_vcpu *vcpu) svm_flush_tlb_asid(vcpu); } -static void svm_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t gva) +static void svm_flush_tlb_guest(struct kvm_vcpu *vcpu) { - struct vcpu_svm *svm = to_svm(vcpu); + kvm_register_mark_dirty(vcpu, VCPU_REG_ERAPS); - invlpga(gva, svm->vmcb->control.asid); + svm_flush_tlb_asid(vcpu); } -static void svm_flush_tlb_guest(struct kvm_vcpu *vcpu) +static void svm_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t gva, bool *full) { - kvm_register_mark_dirty(vcpu, VCPU_REG_ERAPS); + struct vcpu_svm *svm = to_svm(vcpu); - svm_flush_tlb_asid(vcpu); + /* + * INVLPGA has had errata on Genoa and Turin, and even on older + * generations there were reports of Windows BSODs if INVLPGA + * was used for Hyper-V tlbflush. Use it only for shadow paging + * where it seems to be okay. + */ + if (!npt_enabled) { + invlpga(gva, svm->vmcb->control.asid); + return; + } + + svm_flush_tlb_guest(vcpu); + if (full) + *full = true; } static inline void sync_cr8_to_lapic(struct kvm_vcpu *vcpu) diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c index 83d9921277ea..f204a0fc0a57 100644 --- a/arch/x86/kvm/vmx/main.c +++ b/arch/x86/kvm/vmx/main.c @@ -535,12 +535,12 @@ static void vt_flush_tlb_current(struct kvm_vcpu *vcpu) vmx_flush_tlb_current(vcpu); } -static void vt_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t addr) +static void vt_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t addr, bool *full) { if (is_td_vcpu(vcpu)) return; - vmx_flush_tlb_gva(vcpu, addr); + vmx_flush_tlb_gva(vcpu, addr, full); } static void vt_flush_tlb_guest(struct kvm_vcpu *vcpu) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index cc75feec05da..b8d745f6fd22 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -3361,7 +3361,7 @@ void vmx_flush_tlb_current(struct kvm_vcpu *vcpu) vpid_sync_context(vmx_get_current_vpid(vcpu)); } -void vmx_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t addr) +void vmx_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t addr, bool *full) { /* * vpid_sync_vcpu_addr() is a nop if vpid==0, see the comment in diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h index 409858074246..17595d52985c 100644 --- a/arch/x86/kvm/vmx/x86_ops.h +++ b/arch/x86/kvm/vmx/x86_ops.h @@ -82,7 +82,7 @@ void vmx_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags); bool vmx_get_if_flag(struct kvm_vcpu *vcpu); void vmx_flush_tlb_all(struct kvm_vcpu *vcpu); void vmx_flush_tlb_current(struct kvm_vcpu *vcpu); -void vmx_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t addr); +void vmx_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t addr, bool *full); void vmx_flush_tlb_guest(struct kvm_vcpu *vcpu); void vmx_set_interrupt_shadow(struct kvm_vcpu *vcpu, int mask); u32 vmx_get_interrupt_shadow(struct kvm_vcpu *vcpu); -- cgit v1.2.3 From 1d78d33275ef2a16c6d080910b291d0a97a0e613 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 6 Aug 2026 16:44:17 +0200 Subject: KVM: SVM: Serialize accesses to the owner and mirror list with separate lock Interaction between KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM and KVM_CAP_VM_COPY_ENC_CONTEXT_FROM can cause two separate issues: - in sev_migrate_from(), when the destination KVM is a mirror, the mirror entry is moved from the source's list to the owner's mirror_vms list, without holding the owner's lock unlike other writers of the owner's mirror list (sev_vm_copy_enc_context_from(), sev_vm_destroy()). A concurrent COPY or destroy can race with sev_migrate_from() and corrupt the list. - In sev_vm_destroy(), the *owner* is still active and could receive concurrently a KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM that causes sev->enc_context_owner to change. In this case the incorrect VM receives kvm_put_kvm(). The second issue needs particular care because the owner could disappear altogether (even though the race window is impossibly small) between reading it and locking it. There is thus no way to perform the checks under the owner lock without putting struct kvm under SLAB_TYPESAFE_BY_RCU (which would allow kvm_get_kvm_safe() under RCU critical section). It is much simpler to just use a global lock, since the critical sections are so small and the new lock is always a leaf lock. Fixes: b2125513dfc0 ("KVM: SEV: Allow SEV intra-host migration of VM with mirrors") Cc: stable@vger.kernel.org Reported-by: Shen Yongchao Link: https://lore.kernel.org/kvm/tencent_625C0F42824E542C72B34733392AF2C49709@qq.com/ Link: https://lore.kernel.org/kvm/tencent_DDC4E4352EC91CAC05A9A8F4E55E8C96730A@qq.com/ Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/sev.c | 34 +++++++++++++++++++++++++--------- arch/x86/kvm/svm/svm.h | 1 + 2 files changed, 26 insertions(+), 9 deletions(-) (limited to 'arch') diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 944aaea6501f..0f0ea7896af5 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -97,6 +97,8 @@ static u64 sev_supported_vmsa_features __ro_after_init; static u8 sev_enc_bit; static DECLARE_RWSEM(sev_deactivate_lock); static DEFINE_MUTEX(sev_bitmap_lock); +/* Protects kvm_sev_info's enc_context_owner, mirror_vms and mirror_entry. */ +static DEFINE_MUTEX(sev_mirror_lock); unsigned int max_sev_asid; static unsigned int min_sev_asid; static unsigned int max_sev_es_asid; @@ -2018,7 +2020,6 @@ static void sev_migrate_from(struct kvm *dst_kvm, struct kvm *src_kvm) dst->asid = src->asid; dst->handle = src->handle; dst->pages_locked = src->pages_locked; - dst->enc_context_owner = src->enc_context_owner; dst->es_active = src->es_active; dst->vmsa_features = src->vmsa_features; @@ -2026,11 +2027,12 @@ static void sev_migrate_from(struct kvm *dst_kvm, struct kvm *src_kvm) src->active = false; src->handle = 0; src->pages_locked = 0; - src->enc_context_owner = NULL; src->es_active = false; list_cut_before(&dst->regions_list, &src->regions_list, &src->regions_list); + mutex_lock(&sev_mirror_lock); + /* * If this VM has mirrors, "transfer" each mirror's refcount of the * source to the destination (this KVM). The caller holds a reference @@ -2047,12 +2049,15 @@ static void sev_migrate_from(struct kvm *dst_kvm, struct kvm *src_kvm) * If this VM is a mirror, remove the old mirror from the owners list * and add the new mirror to the list. */ - if (is_mirroring_enc_context(dst_kvm)) { - struct kvm_sev_info *owner_sev_info = to_kvm_sev_info(dst->enc_context_owner); + if (is_mirroring_enc_context(src_kvm)) { + struct kvm_sev_info *owner_sev_info = to_kvm_sev_info(src->enc_context_owner); + dst->enc_context_owner = src->enc_context_owner; + src->enc_context_owner = NULL; list_del(&src->mirror_entry); list_add_tail(&dst->mirror_entry, &owner_sev_info->mirror_vms); } + mutex_unlock(&sev_mirror_lock); kvm_for_each_vcpu(i, dst_vcpu, dst_kvm) { dst_svm = to_svm(dst_vcpu); @@ -2871,11 +2876,14 @@ int sev_vm_copy_enc_context_from(struct kvm *kvm, unsigned int source_fd) * disappear until we're done with it */ source_sev = to_kvm_sev_info(source_kvm); - kvm_get_kvm(source_kvm); - list_add_tail(&mirror_sev->mirror_entry, &source_sev->mirror_vms); /* Set enc_context_owner and copy its encryption context over */ + mutex_lock(&sev_mirror_lock); + kvm_get_kvm(source_kvm); + list_add_tail(&mirror_sev->mirror_entry, &source_sev->mirror_vms); mirror_sev->enc_context_owner = source_kvm; + mutex_unlock(&sev_mirror_lock); + mirror_sev->active = true; mirror_sev->asid = source_sev->asid; mirror_sev->fd = source_sev->fd; @@ -2963,11 +2971,19 @@ void sev_vm_destroy(struct kvm *kvm) * Note, mirror VMs don't support registering encrypted regions. */ if (is_mirroring_enc_context(kvm)) { - struct kvm *owner_kvm = sev->enc_context_owner; + struct kvm *owner_kvm; - mutex_lock(&owner_kvm->lock); + mutex_lock(&sev_mirror_lock); + owner_kvm = sev->enc_context_owner; list_del(&sev->mirror_entry); - mutex_unlock(&owner_kvm->lock); + sev->enc_context_owner = NULL; + + /* + * The reference to owner_kvm cannot move after sev_mirror_lock is + * released. Release it before kvm_put_kvm() so that owner_kvm is + * never destroyed inside sev_mirror_lock. + */ + mutex_unlock(&sev_mirror_lock); kvm_put_kvm(owner_kvm); return; } diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 716be21fba33..d63e5878988a 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -109,6 +109,7 @@ struct kvm_sev_info { u64 ap_jump_table; /* SEV-ES AP Jump Table address */ u64 vmsa_features; u16 ghcb_version; /* Highest guest GHCB protocol version allowed */ + /* The three fields below are protected by sev_mirror_lock */ struct kvm *enc_context_owner; /* Owner of copied encryption context */ struct list_head mirror_vms; /* List of VMs mirroring */ struct list_head mirror_entry; /* Use as a list entry of mirrors */ -- cgit v1.2.3 From 5ec42d57655c690234c14aece6dd3f209778c1d8 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Mon, 13 Jul 2026 08:25:49 -0700 Subject: KVM: x86/mmu: WARN and clear role.invalid when creating a child shadow page Explicitly clear role.invalid when deriving a child shadow page's role from its parent to harden against bugs elsewhere in KVM, as violating KVM's invariant that invalid pages are NOT on the list of active MMU pages leads to use-after-free due to __kvm_mmu_prepare_zap_page() using list_add() instead of list_move() when processing an invalid shadow page, i.e. makes a bad situation far worse. Yell loudly if the parent is invalid, as it means KVM has missed a validity check, i.e. KVM is attempting to map memory using an invalid/obsolete root, but continue on as the child is otherwise still a valid shadow page. ================================================================== BUG: KASAN: slab-use-after-free in __kvm_mmu_get_shadow_page+0x1817/0x1860 [kvm] Write of size 8 at addr ff11000153dd1368 by task repro/853 CPU: 1 UID: 1000 PID: 853 Comm: repro Not tainted 7.2.0-rc2-3aec122bdcaf-next-vm #5 PREEMPT Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Call Trace: dump_stack_lvl+0x4b/0x70 print_report+0x153/0x49c kasan_report+0xbc/0xf0 __kvm_mmu_get_shadow_page+0x1817/0x1860 [kvm] mmu_alloc_root+0x141/0x320 [kvm] kvm_mmu_load+0x612/0x20f0 [kvm] kvm_arch_vcpu_ioctl_run+0x3dd5/0x6150 [kvm] kvm_vcpu_ioctl+0x5e4/0x10d0 [kvm] __x64_sys_ioctl+0x131/0x1b0 do_syscall_64+0x67/0x5f0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Allocated by task 853: kasan_save_stack+0x20/0x40 kasan_save_track+0x14/0x30 __kasan_slab_alloc+0x5f/0x70 kmem_cache_alloc_noprof+0xfe/0x2e0 __kvm_mmu_topup_memory_cache+0x135/0x530 [kvm] paging64_page_fault+0x318/0x1e30 [kvm] kvm_mmu_do_page_fault+0x21d/0x630 [kvm] kvm_mmu_page_fault+0x18c/0x17b0 [kvm] kvm_arch_vcpu_ioctl_run+0x1f35/0x6150 [kvm] kvm_vcpu_ioctl+0x5e4/0x10d0 [kvm] __x64_sys_ioctl+0x131/0x1b0 do_syscall_64+0x67/0x5f0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Freed by task 853: kasan_save_stack+0x20/0x40 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3b/0x60 __kasan_slab_free+0x43/0x70 kmem_cache_free+0xe2/0x400 kvm_mmu_commit_zap_page.part.0+0x1e2/0x310 [kvm] kvm_mmu_free_roots+0x283/0x560 [kvm] kvm_arch_vcpu_ioctl_run+0x33c8/0x6150 [kvm] kvm_vcpu_ioctl+0x5e4/0x10d0 [kvm] __x64_sys_ioctl+0x131/0x1b0 do_syscall_64+0x67/0x5f0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Reported-by: Hyunwoo Kim Fixes: a770f6f28b1a ("KVM: MMU: Inherit a shadow page's guest level count from vcpu setup") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu/mmu.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch') diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index c9e4739b26d7..a61750f8e1e3 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2442,6 +2442,9 @@ static union kvm_mmu_page_role kvm_mmu_child_role(u64 *sptep, bool direct, role.direct = direct; role.passthrough = 0; + WARN_ON_ONCE(role.invalid); + role.invalid = 0; + /* * If the guest has 4-byte PTEs then that means it's using 32-bit, * 2-level, non-PAE paging. KVM shadows such guests with PAE paging -- cgit v1.2.3 From 5b17f3f34391372faf03e79d947e0c50ab6dd258 Mon Sep 17 00:00:00 2001 From: George Wilson Date: Fri, 7 Aug 2026 11:56:21 -0500 Subject: powerpc/pseries: papr-phy-attest - validate cmd.length, plug mem leak In papr_phy_attest_create_handle(), the params->cmd.length is not validated before use, which can result in a buffer overlow. Check it and return -EINVAL if it is either 0 or exceeds sizeof(params->cmd). Also, params is freed on the success path but not error. Free it on errors after memory allocation. And free it on negative fd. Fixes: 86900ab620a4 ("powerpc/pseries: Add a char driver for physical-attestation RTAS") Acked-by: Haren Myneni Acked-by: Nayna Jain Tested-by: R Nageswara Sastry Cc: stable@vger.kernel.org # 6.16 Signed-off-by: George Wilson Signed-off-by: Madhavan Srinivasan --- arch/powerpc/platforms/pseries/papr-phy-attest.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/powerpc/platforms/pseries/papr-phy-attest.c b/arch/powerpc/platforms/pseries/papr-phy-attest.c index 20a0e1581302..350ba26e5962 100644 --- a/arch/powerpc/platforms/pseries/papr-phy-attest.c +++ b/arch/powerpc/platforms/pseries/papr-phy-attest.c @@ -230,10 +230,17 @@ static long papr_phy_attest_create_handle(struct papr_phy_attest_io_block __user return -ENOMEM; if (copy_from_user(¶ms->cmd, ulc, - sizeof(struct papr_phy_attest_io_block))) + sizeof(struct papr_phy_attest_io_block))) { + kfree(params); return -EFAULT; + } params->cmd_len = be32_to_cpu(params->cmd.length); + if (params->cmd_len == 0 || params->cmd_len > sizeof(params->cmd)) { + kfree(params); + return -EINVAL; + } + seq = (struct papr_rtas_sequence) { .begin = phy_attest_sequence_begin, .end = phy_attest_sequence_end, @@ -246,6 +253,9 @@ static long papr_phy_attest_create_handle(struct papr_phy_attest_io_block __user &papr_phy_attest_handle_ops, "[papr-physical-attestation]"); + if (fd < 0) + kfree(params); + return fd; } -- cgit v1.2.3 From 649c10bff5cb7a514bf299094833ec8c9190aac3 Mon Sep 17 00:00:00 2001 From: George Wilson Date: Fri, 7 Aug 2026 11:58:36 -0500 Subject: powerpc/pseries: pci - logic bug The checks on num_vfs in pseries_pci_sriov_enable() are ANDed where OR was apparently intended. Change it to OR. Fixes: 9a7f6b438664 ("powerpc/pseries/pci: Associate PEs to VFs in configure SR-IOV") Acked-by: Nayna Jain Tested-by: R Nageswara Sastry Cc: stable@vger.kernel.org # 4.16 Signed-off-by: George Wilson Signed-off-by: Madhavan Srinivasan --- arch/powerpc/platforms/pseries/pci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/powerpc/platforms/pseries/pci.c b/arch/powerpc/platforms/pseries/pci.c index 84e4ffe957a8..d11a64a086c1 100644 --- a/arch/powerpc/platforms/pseries/pci.c +++ b/arch/powerpc/platforms/pseries/pci.c @@ -132,7 +132,7 @@ static int pseries_pci_sriov_enable(struct pci_dev *pdev, u16 num_vfs) /* First integer stores max config */ max_config_vfs = of_read_number(&max_vfs[0], 1); - if (max_config_vfs < num_vfs && num_vfs > MAX_VFS_FOR_MAP_PE) { + if (max_config_vfs < num_vfs || num_vfs > MAX_VFS_FOR_MAP_PE) { dev_err(&pdev->dev, "Num VFs %x > %x Configurable VFs\n", num_vfs, (num_vfs > MAX_VFS_FOR_MAP_PE) ? -- cgit v1.2.3 From fb442a6673ff1046bf67754957d95880fdb394b5 Mon Sep 17 00:00:00 2001 From: George Wilson Date: Fri, 7 Aug 2026 11:59:00 -0500 Subject: powerpc/pseries: lparcfg - fix kbuf[] underflow In lparcfg_write(), a count of 0 results in kbuf[] being indexed at -1. Check for count == 0 in the existing check for count > sizeof(kbuf) and return -EINVAL if true. Fixes: 74422e2b1939 ("powerpc/pseries: Remove VLA from lparcfg_write()") Acked-by: Nayna Jain Tested-by: R Nageswara Sastry Cc: stable@vger.kernel.org # 4.20 Signed-off-by: George Wilson Signed-off-by: Madhavan Srinivasan --- arch/powerpc/platforms/pseries/lparcfg.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/powerpc/platforms/pseries/lparcfg.c b/arch/powerpc/platforms/pseries/lparcfg.c index 54b7ecf375b5..3280b7968cab 100644 --- a/arch/powerpc/platforms/pseries/lparcfg.c +++ b/arch/powerpc/platforms/pseries/lparcfg.c @@ -699,7 +699,7 @@ static ssize_t lparcfg_write(struct file *file, const char __user * buf, if (!firmware_has_feature(FW_FEATURE_SPLPAR)) return -EINVAL; - if (count > sizeof(kbuf)) + if (count == 0 || count > sizeof(kbuf)) return -EINVAL; if (copy_from_user(kbuf, buf, count)) -- cgit v1.2.3 From 1fd495ef09eef96169a379a749c24b5e69974bb8 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Date: Fri, 31 Jul 2026 11:49:49 +0200 Subject: m68k: Define NR_CPUS to 1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This fixes a Kconfig warning fs/erofs/Kconfig:137:warning: range is invalid which originates from EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS using NR_CPUS which up to now didn't exist for ARCH=m68k. All other architectures define this symbol, so fix the outlier. [geert] This also fixes: - CONFIG_EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS being set to the literal NR_CPUS instead of a number by automatic configs like "make allmodconfig" or "make olddefconfig", - An infinite loop in manual configs like "make oldconfig" when CONFIG_EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS is not present or has an invalid value in your existing .config. Fixes: c9b47e6b2311 ("erofs: cap LZMA stream pool size") Signed-off-by: Uwe Kleine-König Reviewed-by: Geert Uytterhoeven Link: https://patch.msgid.link/20260731094950.1988084-2-ukleinek@kernel.org Signed-off-by: Geert Uytterhoeven --- arch/m68k/Kconfig.cpu | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch') diff --git a/arch/m68k/Kconfig.cpu b/arch/m68k/Kconfig.cpu index 148f8a79d206..5a58cc13229e 100644 --- a/arch/m68k/Kconfig.cpu +++ b/arch/m68k/Kconfig.cpu @@ -549,6 +549,10 @@ config CACHE_COPYBACK endchoice endif # HAVE_CACHE_CB +config NR_CPUS + int + default "1" + # Coldfire cores that do not have a data cache configured can do coherent DMA. config COLDFIRE_COHERENT_DMA bool -- cgit v1.2.3