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Subject[RFC 07/19] KVM: x86/mmu: Factor wrprot for nested PML out of make_spte
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When running a nested VM, KVM write protects SPTEs in the EPT/NPT02
instead of using PML for dirty tracking. This avoids expensive
translation later, when emptying the Page Modification Log. In service
of removing the vCPU pointer from make_spte, factor the check for nested
PML out of the function.


Signed-off-by: Ben Gardon <bgardon@google.com>
---
arch/x86/kvm/mmu/spte.c | 10 +++++++---
arch/x86/kvm/mmu/spte.h | 3 ++-
2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c
index 04d26e913941..3cf08a534a16 100644
--- a/arch/x86/kvm/mmu/spte.c
+++ b/arch/x86/kvm/mmu/spte.c
@@ -92,7 +92,8 @@ static bool kvm_is_mmio_pfn(kvm_pfn_t pfn)
bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
struct kvm_memory_slot *slot, unsigned int pte_access,
gfn_t gfn, kvm_pfn_t pfn, u64 old_spte, bool prefetch,
- bool can_unsync, bool host_writable, u64 *new_spte)
+ bool can_unsync, bool host_writable, bool ad_need_write_protect,
+ u64 *new_spte)
{
int level = sp->role.level;
u64 spte = SPTE_MMU_PRESENT_MASK;
@@ -100,7 +101,7 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,

if (sp->role.ad_disabled)
spte |= SPTE_TDP_AD_DISABLED_MASK;
- else if (kvm_vcpu_ad_need_write_protect(vcpu))
+ else if (ad_need_write_protect)
spte |= SPTE_TDP_AD_WRPROT_ONLY_MASK;

/*
@@ -195,8 +196,11 @@ bool vcpu_make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
gfn_t gfn, kvm_pfn_t pfn, u64 old_spte, bool prefetch,
bool can_unsync, bool host_writable, u64 *new_spte)
{
+ bool ad_need_write_protect = kvm_vcpu_ad_need_write_protect(vcpu);
+
return make_spte(vcpu, sp, slot, pte_access, gfn, pfn, old_spte,
- prefetch, can_unsync, host_writable, new_spte);
+ prefetch, can_unsync, host_writable,
+ ad_need_write_protect, new_spte);

}

diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h
index 14f18082d505..bcf58602f224 100644
--- a/arch/x86/kvm/mmu/spte.h
+++ b/arch/x86/kvm/mmu/spte.h
@@ -332,7 +332,8 @@ static inline u64 get_mmio_spte_generation(u64 spte)
bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
struct kvm_memory_slot *slot, unsigned int pte_access,
gfn_t gfn, kvm_pfn_t pfn, u64 old_spte, bool prefetch,
- bool can_unsync, bool host_writable, u64 *new_spte);
+ bool can_unsync, bool host_writable, bool ad_need_write_protect,
+ u64 *new_spte);
bool vcpu_make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
struct kvm_memory_slot *slot,
unsigned int pte_access, gfn_t gfn, kvm_pfn_t pfn,
--
2.34.0.rc0.344.g81b53c2807-goog
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