diff options
| author | Eric Farman <farman@linux.ibm.com> | 2026-04-01 17:12:18 +0200 |
|---|---|---|
| committer | Janosch Frank <frankja@linux.ibm.com> | 2026-04-02 15:37:01 +0200 |
| commit | b0ad874d9852967dafdb94b1632e0732e01e6cd8 (patch) | |
| tree | 951571e96489bf727bbbd5a36a146b625ab12201 | |
| parent | 1653545abc6835ab723c02697a5e2964e98e2c53 (diff) | |
KVM: s390: vsie: Allow non-zarch guests
Linux/KVM runs in z/Architecture-only mode. Although z/Architecture
is built upon a long history of hardware refinements, any other
CPU mode is not permitted.
Allow a userspace to explicitly enable the use of ESA mode for
nested guests, otherwise usage will be rejected.
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
| -rw-r--r-- | arch/s390/include/asm/kvm_host.h | 1 | ||||
| -rw-r--r-- | arch/s390/kvm/vsie.c | 8 |
2 files changed, 6 insertions, 3 deletions
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 64a50f0862aa..b58faad8a7ce 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -656,6 +656,7 @@ struct kvm_arch { int user_stsi; int user_instr0; int user_operexec; + int allow_vsie_esamode; struct s390_io_adapter *adapters[MAX_S390_IO_ADAPTERS]; wait_queue_head_t ipte_wq; int ipte_lock_count; diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c index d249b10044eb..aa43c6848217 100644 --- a/arch/s390/kvm/vsie.c +++ b/arch/s390/kvm/vsie.c @@ -125,8 +125,8 @@ static int prepare_cpuflags(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) struct kvm_s390_sie_block *scb_o = vsie_page->scb_o; int newflags, cpuflags = atomic_read(&scb_o->cpuflags); - /* we don't allow ESA/390 guests */ - if (!(cpuflags & CPUSTAT_ZARCH)) + /* we don't allow ESA/390 guests unless explicitly enabled */ + if (!(cpuflags & CPUSTAT_ZARCH) && !vcpu->kvm->arch.allow_vsie_esamode) return set_validity_icpt(scb_s, 0x0001U); if (cpuflags & (CPUSTAT_RRF | CPUSTAT_MCDS)) @@ -135,7 +135,9 @@ static int prepare_cpuflags(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) return set_validity_icpt(scb_s, 0x0007U); /* intervention requests will be set later */ - newflags = CPUSTAT_ZARCH; + newflags = 0; + if (cpuflags & CPUSTAT_ZARCH) + newflags = CPUSTAT_ZARCH; if (cpuflags & CPUSTAT_GED && test_kvm_facility(vcpu->kvm, 8)) newflags |= CPUSTAT_GED; if (cpuflags & CPUSTAT_GED2 && test_kvm_facility(vcpu->kvm, 78)) { |