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authorSean Christopherson <seanjc@google.com>2023-07-28 17:51:56 -0700
committerPaolo Bonzini <pbonzini@redhat.com>2023-08-31 14:08:20 -0400
commitc5f2d5645f9b7c12c9546ced9ec1f1a558870747 (patch)
tree747b268321df2a35d528759a9f30d741f710c89b /arch/x86/kvm/mmu
parent09c8726ffa4a8309af7653988694b6cae6abf723 (diff)
KVM: x86/mmu: Add helper to convert root hpa to shadow page
Add a dedicated helper for converting a root hpa to a shadow page in anticipation of using a "dummy" root to handle the scenario where KVM needs to load a valid shadow root (from hardware's perspective), but the guest doesn't have a visible root to shadow. Similar to PAE roots, the dummy root won't have an associated kvm_mmu_page and will need special handling when finding a shadow page given a root. Opportunistically retrieve the root shadow page in kvm_mmu_sync_roots() *after* verifying the root is unsync (the dummy root can never be unsync). Link: https://lore.kernel.org/r/20230729005200.1057358-2-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu')
-rw-r--r--arch/x86/kvm/mmu/mmu.c28
-rw-r--r--arch/x86/kvm/mmu/spte.h9
-rw-r--r--arch/x86/kvm/mmu/tdp_mmu.c2
3 files changed, 23 insertions, 16 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 060849d6aadf..61b67a7d61e0 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3543,11 +3543,7 @@ static void mmu_free_root_page(struct kvm *kvm, hpa_t *root_hpa,
if (!VALID_PAGE(*root_hpa))
return;
- /*
- * The "root" may be a special root, e.g. a PAE entry, treat it as a
- * SPTE to ensure any non-PA bits are dropped.
- */
- sp = spte_to_child_sp(*root_hpa);
+ sp = root_to_sp(*root_hpa);
if (WARN_ON_ONCE(!sp))
return;
@@ -3593,7 +3589,7 @@ void kvm_mmu_free_roots(struct kvm *kvm, struct kvm_mmu *mmu,
&invalid_list);
if (free_active_root) {
- if (to_shadow_page(mmu->root.hpa)) {
+ if (root_to_sp(mmu->root.hpa)) {
mmu_free_root_page(kvm, &mmu->root.hpa, &invalid_list);
} else if (mmu->pae_root) {
for (i = 0; i < 4; ++i) {
@@ -3617,6 +3613,7 @@ EXPORT_SYMBOL_GPL(kvm_mmu_free_roots);
void kvm_mmu_free_guest_mode_roots(struct kvm *kvm, struct kvm_mmu *mmu)
{
unsigned long roots_to_free = 0;
+ struct kvm_mmu_page *sp;
hpa_t root_hpa;
int i;
@@ -3631,8 +3628,8 @@ void kvm_mmu_free_guest_mode_roots(struct kvm *kvm, struct kvm_mmu *mmu)
if (!VALID_PAGE(root_hpa))
continue;
- if (!to_shadow_page(root_hpa) ||
- to_shadow_page(root_hpa)->role.guest_mode)
+ sp = root_to_sp(root_hpa);
+ if (!sp || sp->role.guest_mode)
roots_to_free |= KVM_MMU_ROOT_PREVIOUS(i);
}
@@ -3987,7 +3984,7 @@ static bool is_unsync_root(hpa_t root)
* requirement isn't satisfied.
*/
smp_rmb();
- sp = to_shadow_page(root);
+ sp = root_to_sp(root);
/*
* PAE roots (somewhat arbitrarily) aren't backed by shadow pages, the
@@ -4017,11 +4014,12 @@ void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
if (vcpu->arch.mmu->cpu_role.base.level >= PT64_ROOT_4LEVEL) {
hpa_t root = vcpu->arch.mmu->root.hpa;
- sp = to_shadow_page(root);
if (!is_unsync_root(root))
return;
+ sp = root_to_sp(root);
+
write_lock(&vcpu->kvm->mmu_lock);
mmu_sync_children(vcpu, sp, true);
write_unlock(&vcpu->kvm->mmu_lock);
@@ -4351,7 +4349,7 @@ static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
static bool is_page_fault_stale(struct kvm_vcpu *vcpu,
struct kvm_page_fault *fault)
{
- struct kvm_mmu_page *sp = to_shadow_page(vcpu->arch.mmu->root.hpa);
+ struct kvm_mmu_page *sp = root_to_sp(vcpu->arch.mmu->root.hpa);
/* Special roots, e.g. pae_root, are not backed by shadow pages. */
if (sp && is_obsolete_sp(vcpu->kvm, sp))
@@ -4531,7 +4529,7 @@ static inline bool is_root_usable(struct kvm_mmu_root_info *root, gpa_t pgd,
{
return (role.direct || pgd == root->pgd) &&
VALID_PAGE(root->hpa) &&
- role.word == to_shadow_page(root->hpa)->role.word;
+ role.word == root_to_sp(root->hpa)->role.word;
}
/*
@@ -4605,7 +4603,7 @@ static bool fast_pgd_switch(struct kvm *kvm, struct kvm_mmu *mmu,
* having to deal with PDPTEs. We may add support for 32-bit hosts/VMs
* later if necessary.
*/
- if (VALID_PAGE(mmu->root.hpa) && !to_shadow_page(mmu->root.hpa))
+ if (VALID_PAGE(mmu->root.hpa) && !root_to_sp(mmu->root.hpa))
kvm_mmu_free_roots(kvm, mmu, KVM_MMU_ROOT_CURRENT);
if (VALID_PAGE(mmu->root.hpa))
@@ -4653,7 +4651,7 @@ void kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd)
*/
if (!new_role.direct)
__clear_sp_write_flooding_count(
- to_shadow_page(vcpu->arch.mmu->root.hpa));
+ root_to_sp(vcpu->arch.mmu->root.hpa));
}
EXPORT_SYMBOL_GPL(kvm_mmu_new_pgd);
@@ -5508,7 +5506,7 @@ static bool is_obsolete_root(struct kvm *kvm, hpa_t root_hpa)
* (c) KVM doesn't track previous roots for PAE paging, and the guest
* is unlikely to zap an in-use PGD.
*/
- sp = to_shadow_page(root_hpa);
+ sp = root_to_sp(root_hpa);
return !sp || is_obsolete_sp(kvm, sp);
}
diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h
index 83e6614f3720..29e0c1c8caa6 100644
--- a/arch/x86/kvm/mmu/spte.h
+++ b/arch/x86/kvm/mmu/spte.h
@@ -236,6 +236,15 @@ static inline struct kvm_mmu_page *sptep_to_sp(u64 *sptep)
return to_shadow_page(__pa(sptep));
}
+static inline struct kvm_mmu_page *root_to_sp(hpa_t root)
+{
+ /*
+ * The "root" may be a special root, e.g. a PAE entry, treat it as a
+ * SPTE to ensure any non-PA bits are dropped.
+ */
+ return spte_to_child_sp(root);
+}
+
static inline bool is_mmio_spte(u64 spte)
{
return (spte & shadow_mmio_mask) == shadow_mmio_value &&
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index fda32a72b406..6c63f2d1675f 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -689,7 +689,7 @@ static inline void tdp_mmu_iter_set_spte(struct kvm *kvm, struct tdp_iter *iter,
else
#define tdp_mmu_for_each_pte(_iter, _mmu, _start, _end) \
- for_each_tdp_pte(_iter, to_shadow_page(_mmu->root.hpa), _start, _end)
+ for_each_tdp_pte(_iter, root_to_sp(_mmu->root.hpa), _start, _end)
/*
* Yield if the MMU lock is contended or this thread needs to return control