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-rw-r--r--arch/mips/include/asm/kvm_host.h13
-rw-r--r--arch/mips/kvm/Kconfig1
-rw-r--r--arch/mips/kvm/mips.c1
-rw-r--r--arch/mips/kvm/mmu.c235
4 files changed, 233 insertions, 17 deletions
diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index a7394940119c..718dfffa17d5 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -663,6 +663,19 @@ enum kvm_mips_fault_result kvm_trap_emul_gva_fault(struct kvm_vcpu *vcpu,
unsigned long gva,
bool write);
+#define KVM_ARCH_WANT_MMU_NOTIFIER
+int kvm_unmap_hva(struct kvm *kvm, unsigned long hva);
+int kvm_unmap_hva_range(struct kvm *kvm,
+ unsigned long start, unsigned long end);
+void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte);
+int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end);
+int kvm_test_age_hva(struct kvm *kvm, unsigned long hva);
+
+static inline void kvm_arch_mmu_notifier_invalidate_page(struct kvm *kvm,
+ unsigned long address)
+{
+}
+
/* Emulation */
int kvm_get_inst(u32 *opc, struct kvm_vcpu *vcpu, u32 *out);
enum emulation_result update_pc(struct kvm_vcpu *vcpu, u32 cause);
diff --git a/arch/mips/kvm/Kconfig b/arch/mips/kvm/Kconfig
index 85c4593b634a..65067327db12 100644
--- a/arch/mips/kvm/Kconfig
+++ b/arch/mips/kvm/Kconfig
@@ -22,6 +22,7 @@ config KVM
select ANON_INODES
select KVM_GENERIC_DIRTYLOG_READ_PROTECT
select KVM_MMIO
+ select MMU_NOTIFIER
select SRCU
---help---
Support for hosting Guest kernels.
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 475c4cc78bd6..9932f53a1e5c 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -1217,6 +1217,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
switch (ext) {
case KVM_CAP_ONE_REG:
case KVM_CAP_ENABLE_CAP:
+ case KVM_CAP_SYNC_MMU:
r = 1;
break;
case KVM_CAP_COALESCED_MMIO:
diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c
index 8a01bbd276fc..cb0faade311e 100644
--- a/arch/mips/kvm/mmu.c
+++ b/arch/mips/kvm/mmu.c
@@ -194,7 +194,6 @@ static bool kvm_mips_flush_gpa_pte(pte_t *pte, unsigned long start_gpa,
if (!pte_present(pte[i]))
continue;
- kvm_release_pfn_clean(pte_pfn(pte[i]));
set_pte(pte + i, __pte(0));
}
return safe_to_remove;
@@ -450,6 +449,155 @@ void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
kvm_mips_mkclean_gpa_pt(kvm, start, end);
}
+/*
+ * kvm_mips_mkold_gpa_pt.
+ * Mark a range of guest physical address space old (all accesses fault) in the
+ * VM's GPA page table to allow detection of commonly used pages.
+ */
+
+BUILD_PTE_RANGE_OP(mkold, pte_mkold)
+
+static int kvm_mips_mkold_gpa_pt(struct kvm *kvm, gfn_t start_gfn,
+ gfn_t end_gfn)
+{
+ return kvm_mips_mkold_pgd(kvm->arch.gpa_mm.pgd,
+ start_gfn << PAGE_SHIFT,
+ end_gfn << PAGE_SHIFT);
+}
+
+static int handle_hva_to_gpa(struct kvm *kvm,
+ unsigned long start,
+ unsigned long end,
+ int (*handler)(struct kvm *kvm, gfn_t gfn,
+ gpa_t gfn_end,
+ struct kvm_memory_slot *memslot,
+ void *data),
+ void *data)
+{
+ struct kvm_memslots *slots;
+ struct kvm_memory_slot *memslot;
+ int ret = 0;
+
+ slots = kvm_memslots(kvm);
+
+ /* we only care about the pages that the guest sees */
+ kvm_for_each_memslot(memslot, slots) {
+ unsigned long hva_start, hva_end;
+ gfn_t gfn, gfn_end;
+
+ hva_start = max(start, memslot->userspace_addr);
+ hva_end = min(end, memslot->userspace_addr +
+ (memslot->npages << PAGE_SHIFT));
+ if (hva_start >= hva_end)
+ continue;
+
+ /*
+ * {gfn(page) | page intersects with [hva_start, hva_end)} =
+ * {gfn_start, gfn_start+1, ..., gfn_end-1}.
+ */
+ gfn = hva_to_gfn_memslot(hva_start, memslot);
+ gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot);
+
+ ret |= handler(kvm, gfn, gfn_end, memslot, data);
+ }
+
+ return ret;
+}
+
+
+static int kvm_unmap_hva_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end,
+ struct kvm_memory_slot *memslot, void *data)
+{
+ kvm_mips_flush_gpa_pt(kvm, gfn, gfn_end);
+ return 1;
+}
+
+int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
+{
+ unsigned long end = hva + PAGE_SIZE;
+
+ handle_hva_to_gpa(kvm, hva, end, &kvm_unmap_hva_handler, NULL);
+
+ kvm_mips_callbacks->flush_shadow_all(kvm);
+ return 0;
+}
+
+int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end)
+{
+ handle_hva_to_gpa(kvm, start, end, &kvm_unmap_hva_handler, NULL);
+
+ kvm_mips_callbacks->flush_shadow_all(kvm);
+ return 0;
+}
+
+static int kvm_set_spte_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end,
+ struct kvm_memory_slot *memslot, void *data)
+{
+ gpa_t gpa = gfn << PAGE_SHIFT;
+ pte_t hva_pte = *(pte_t *)data;
+ pte_t *gpa_pte = kvm_mips_pte_for_gpa(kvm, NULL, gpa);
+ pte_t old_pte;
+
+ if (!gpa_pte)
+ return 0;
+
+ /* Mapping may need adjusting depending on memslot flags */
+ old_pte = *gpa_pte;
+ if (memslot->flags & KVM_MEM_LOG_DIRTY_PAGES && !pte_dirty(old_pte))
+ hva_pte = pte_mkclean(hva_pte);
+ else if (memslot->flags & KVM_MEM_READONLY)
+ hva_pte = pte_wrprotect(hva_pte);
+
+ set_pte(gpa_pte, hva_pte);
+
+ /* Replacing an absent or old page doesn't need flushes */
+ if (!pte_present(old_pte) || !pte_young(old_pte))
+ return 0;
+
+ /* Pages swapped, aged, moved, or cleaned require flushes */
+ return !pte_present(hva_pte) ||
+ !pte_young(hva_pte) ||
+ pte_pfn(old_pte) != pte_pfn(hva_pte) ||
+ (pte_dirty(old_pte) && !pte_dirty(hva_pte));
+}
+
+void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
+{
+ unsigned long end = hva + PAGE_SIZE;
+ int ret;
+
+ ret = handle_hva_to_gpa(kvm, hva, end, &kvm_set_spte_handler, &pte);
+ if (ret)
+ kvm_mips_callbacks->flush_shadow_all(kvm);
+}
+
+static int kvm_age_hva_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end,
+ struct kvm_memory_slot *memslot, void *data)
+{
+ return kvm_mips_mkold_gpa_pt(kvm, gfn, gfn_end);
+}
+
+static int kvm_test_age_hva_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end,
+ struct kvm_memory_slot *memslot, void *data)
+{
+ gpa_t gpa = gfn << PAGE_SHIFT;
+ pte_t *gpa_pte = kvm_mips_pte_for_gpa(kvm, NULL, gpa);
+
+ if (!gpa_pte)
+ return 0;
+ return pte_young(*gpa_pte);
+}
+
+int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end)
+{
+ return handle_hva_to_gpa(kvm, start, end, kvm_age_hva_handler, NULL);
+}
+
+int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
+{
+ return handle_hva_to_gpa(kvm, hva, hva, kvm_test_age_hva_handler, NULL);
+}
+
/**
* _kvm_mips_map_page_fast() - Fast path GPA fault handler.
* @vcpu: VCPU pointer.
@@ -460,8 +608,8 @@ void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
* NULL).
*
* Perform fast path GPA fault handling, doing all that can be done without
- * calling into KVM. This handles dirtying of clean pages (for dirty page
- * logging).
+ * calling into KVM. This handles marking old pages young (for idle page
+ * tracking), and dirtying of clean pages (for dirty page logging).
*
* Returns: 0 on success, in which case we can update derived mappings and
* resume guest execution.
@@ -475,6 +623,8 @@ static int _kvm_mips_map_page_fast(struct kvm_vcpu *vcpu, unsigned long gpa,
struct kvm *kvm = vcpu->kvm;
gfn_t gfn = gpa >> PAGE_SHIFT;
pte_t *ptep;
+ kvm_pfn_t pfn = 0; /* silence bogus GCC warning */
+ bool pfn_valid = false;
int ret = 0;
spin_lock(&kvm->mmu_lock);
@@ -486,10 +636,24 @@ static int _kvm_mips_map_page_fast(struct kvm_vcpu *vcpu, unsigned long gpa,
goto out;
}
+ /* Track access to pages marked old */
+ if (!pte_young(*ptep)) {
+ set_pte(ptep, pte_mkyoung(*ptep));
+ pfn = pte_pfn(*ptep);
+ pfn_valid = true;
+ /* call kvm_set_pfn_accessed() after unlock */
+ }
if (write_fault && !pte_dirty(*ptep)) {
- /* Track dirtying of pages */
+ if (!pte_write(*ptep)) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ /* Track dirtying of writeable pages */
set_pte(ptep, pte_mkdirty(*ptep));
+ pfn = pte_pfn(*ptep);
mark_page_dirty(kvm, gfn);
+ kvm_set_pfn_dirty(pfn);
}
if (out_entry)
@@ -499,6 +663,8 @@ static int _kvm_mips_map_page_fast(struct kvm_vcpu *vcpu, unsigned long gpa,
out:
spin_unlock(&kvm->mmu_lock);
+ if (pfn_valid)
+ kvm_set_pfn_accessed(pfn);
return ret;
}
@@ -514,9 +680,10 @@ out:
* Handle GPA faults by creating a new GPA mapping (or updating an existing
* one).
*
- * This takes care of marking pages dirty (dirty page tracking), asking KVM for
- * the corresponding PFN, and creating a mapping in the GPA page tables. Derived
- * mappings (GVA page tables and TLBs) must be handled by the caller.
+ * This takes care of marking pages young or dirty (idle/dirty page tracking),
+ * asking KVM for the corresponding PFN, and creating a mapping in the GPA page
+ * tables. Derived mappings (GVA page tables and TLBs) must be handled by the
+ * caller.
*
* Returns: 0 on success, in which case the caller may use the @out_entry
* and @out_buddy PTEs to update derived mappings and resume guest
@@ -535,9 +702,11 @@ static int kvm_mips_map_page(struct kvm_vcpu *vcpu, unsigned long gpa,
int srcu_idx, err;
kvm_pfn_t pfn;
pte_t *ptep, entry, old_pte;
+ bool writeable;
unsigned long prot_bits;
+ unsigned long mmu_seq;
- /* Try the fast path to handle clean pages */
+ /* Try the fast path to handle old / clean pages */
srcu_idx = srcu_read_lock(&kvm->srcu);
err = _kvm_mips_map_page_fast(vcpu, gpa, write_fault, out_entry,
out_buddy);
@@ -550,33 +719,63 @@ static int kvm_mips_map_page(struct kvm_vcpu *vcpu, unsigned long gpa,
if (err)
goto out;
- /* Slow path - ask KVM core whether we can access this GPA */
- pfn = gfn_to_pfn(kvm, gfn);
+retry:
+ /*
+ * Used to check for invalidations in progress, of the pfn that is
+ * returned by pfn_to_pfn_prot below.
+ */
+ mmu_seq = kvm->mmu_notifier_seq;
+ /*
+ * Ensure the read of mmu_notifier_seq isn't reordered with PTE reads in
+ * gfn_to_pfn_prot() (which calls get_user_pages()), so that we don't
+ * risk the page we get a reference to getting unmapped before we have a
+ * chance to grab the mmu_lock without mmu_notifier_retry() noticing.
+ *
+ * This smp_rmb() pairs with the effective smp_wmb() of the combination
+ * of the pte_unmap_unlock() after the PTE is zapped, and the
+ * spin_lock() in kvm_mmu_notifier_invalidate_<page|range_end>() before
+ * mmu_notifier_seq is incremented.
+ */
+ smp_rmb();
+ /* Slow path - ask KVM core whether we can access this GPA */
+ pfn = gfn_to_pfn_prot(kvm, gfn, write_fault, &writeable);
if (is_error_noslot_pfn(pfn)) {
err = -EFAULT;
goto out;
}
spin_lock(&kvm->mmu_lock);
+ /* Check if an invalidation has taken place since we got pfn */
+ if (mmu_notifier_retry(kvm, mmu_seq)) {
+ /*
+ * This can happen when mappings are changed asynchronously, but
+ * also synchronously if a COW is triggered by
+ * gfn_to_pfn_prot().
+ */
+ spin_unlock(&kvm->mmu_lock);
+ kvm_release_pfn_clean(pfn);
+ goto retry;
+ }
/* Ensure page tables are allocated */
ptep = kvm_mips_pte_for_gpa(kvm, memcache, gpa);
/* Set up the PTE */
- prot_bits = __READABLE | _PAGE_PRESENT | _PAGE_WRITE |
- _page_cachable_default;
- if (write_fault) {
- prot_bits |= __WRITEABLE;
- mark_page_dirty(kvm, gfn);
+ prot_bits = _PAGE_PRESENT | __READABLE | _page_cachable_default;
+ if (writeable) {
+ prot_bits |= _PAGE_WRITE;
+ if (write_fault) {
+ prot_bits |= __WRITEABLE;
+ mark_page_dirty(kvm, gfn);
+ kvm_set_pfn_dirty(pfn);
+ }
}
entry = pfn_pte(pfn, __pgprot(prot_bits));
/* Write the PTE */
old_pte = *ptep;
set_pte(ptep, entry);
- if (pte_present(old_pte))
- kvm_release_pfn_clean(pte_pfn(old_pte));
err = 0;
if (out_entry)
@@ -585,6 +784,8 @@ static int kvm_mips_map_page(struct kvm_vcpu *vcpu, unsigned long gpa,
*out_buddy = *ptep_buddy(ptep);
spin_unlock(&kvm->mmu_lock);
+ kvm_release_pfn_clean(pfn);
+ kvm_set_pfn_accessed(pfn);
out:
srcu_read_unlock(&kvm->srcu, srcu_idx);
return err;
generated by cgit v1.2.3 (git 2.0.4) at 2024-07-06 14:26:03 +0000