Direct roots don't have a write flooding count because the guest can't affect that paging structure. Thus there's no need to clear the write flooding count on a fast CR3 switch for direct roots. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon <bgardon@xxxxxxxxxx> --- arch/x86/kvm/mmu/mmu.c | 15 +++++++++++---- arch/x86/kvm/mmu/tdp_mmu.c | 12 ++++++++++++ arch/x86/kvm/mmu/tdp_mmu.h | 2 ++ 3 files changed, 25 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 0ce7720a72d4e..345c934fabf4c 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4267,7 +4267,8 @@ static void nonpaging_init_context(struct kvm_vcpu *vcpu, context->nx = false; } -static inline bool is_root_usable(struct kvm_mmu_root_info *root, gpa_t pgd, +static inline bool is_root_usable(struct kvm *kvm, + struct kvm_mmu_root_info *root, gpa_t pgd, union kvm_mmu_page_role role) { return (role.direct || pgd == root->pgd) && @@ -4293,13 +4294,13 @@ static bool cached_root_available(struct kvm_vcpu *vcpu, gpa_t new_pgd, root.pgd = mmu->root_pgd; root.hpa = mmu->root_hpa; - if (is_root_usable(&root, new_pgd, new_role)) + if (is_root_usable(vcpu->kvm, &root, new_pgd, new_role)) return true; for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) { swap(root, mmu->prev_roots[i]); - if (is_root_usable(&root, new_pgd, new_role)) + if (is_root_usable(vcpu->kvm, &root, new_pgd, new_role)) break; } @@ -4356,7 +4357,13 @@ static void __kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd, */ vcpu_clear_mmio_info(vcpu, MMIO_GVA_ANY); - __clear_sp_write_flooding_count(to_shadow_page(vcpu->arch.mmu->root_hpa)); + /* + * If this is a direct root page, it doesn't have a write flooding + * count. Otherwise, clear the write flooding count. + */ + if (!new_role.direct) + __clear_sp_write_flooding_count( + to_shadow_page(vcpu->arch.mmu->root_hpa)); } void kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd, bool skip_tlb_flush, diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 42dde27decd75..c07831b0c73e1 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -124,6 +124,18 @@ static struct kvm_mmu_page *find_tdp_mmu_root_with_role( return NULL; } +hpa_t kvm_tdp_mmu_root_hpa_for_role(struct kvm *kvm, + union kvm_mmu_page_role role) +{ + struct kvm_mmu_page *root; + + root = find_tdp_mmu_root_with_role(kvm, role); + if (root) + return __pa(root->spt); + + return INVALID_PAGE; +} + static union kvm_mmu_page_role page_role_for_level(struct kvm_vcpu *vcpu, int level) { diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h index cc0b7241975aa..2395ffa71bb05 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.h +++ b/arch/x86/kvm/mmu/tdp_mmu.h @@ -9,6 +9,8 @@ void kvm_mmu_init_tdp_mmu(struct kvm *kvm); void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm); bool is_tdp_mmu_root(struct kvm *kvm, hpa_t root); +hpa_t kvm_tdp_mmu_root_hpa_for_role(struct kvm *kvm, + union kvm_mmu_page_role role); hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu); void kvm_tdp_mmu_put_root_hpa(struct kvm *kvm, hpa_t root_hpa); -- 2.28.0.709.gb0816b6eb0-goog
