From 5d218814328da91a27e982748443e7e375e11396 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Tue, 12 Mar 2013 22:36:43 -0300 Subject: KVM: MMU: make kvm_mmu_available_pages robust against n_used_mmu_pages > n_max_mmu_pages As noticed by Ulrich Obergfell , the mmu counters are for beancounting purposes only - so n_used_mmu_pages and n_max_mmu_pages could be relaxed (example: before f0f5933a1626c8df7b), resulting in n_used_mmu_pages > n_max_mmu_pages. Make code robust against n_used_mmu_pages > n_max_mmu_pages. Reviewed-by: Xiao Guangrong Signed-off-by: Marcelo Tosatti Signed-off-by: Gleb Natapov --- arch/x86/kvm/mmu.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'arch/x86/kvm/mmu.h') diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index 69871080e866..3b1ad0049ea4 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -57,8 +57,11 @@ int kvm_init_shadow_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *context); static inline unsigned int kvm_mmu_available_pages(struct kvm *kvm) { - return kvm->arch.n_max_mmu_pages - - kvm->arch.n_used_mmu_pages; + if (kvm->arch.n_max_mmu_pages > kvm->arch.n_used_mmu_pages) + return kvm->arch.n_max_mmu_pages - + kvm->arch.n_used_mmu_pages; + + return 0; } static inline void kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu) -- cgit v1.2.3 From 81f4f76bbc712a2dff8bb020057c554e285370e1 Mon Sep 17 00:00:00 2001 From: Takuya Yoshikawa Date: Thu, 21 Mar 2013 19:34:27 +0900 Subject: KVM: MMU: Rename kvm_mmu_free_some_pages() to make_mmu_pages_available() The current name "kvm_mmu_free_some_pages" should be used for something that actually frees some shadow pages, as we expect from the name, but what the function is doing is to make some, KVM_MIN_FREE_MMU_PAGES, shadow pages available: it does nothing when there are enough. This patch changes the name to reflect this meaning better; while doing this renaming, the code in the wrapper function is inlined into the main body since the whole function will be inlined into the only caller now. Signed-off-by: Takuya Yoshikawa Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/mmu.c | 9 +++++++-- arch/x86/kvm/mmu.h | 6 ------ 2 files changed, 7 insertions(+), 8 deletions(-) (limited to 'arch/x86/kvm/mmu.h') diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 38f34c5361f4..633e30cfbd63 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -1501,12 +1501,14 @@ static void drop_parent_pte(struct kvm_mmu_page *sp, mmu_spte_clear_no_track(parent_pte); } +static void make_mmu_pages_available(struct kvm_vcpu *vcpu); + static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, u64 *parent_pte, int direct) { struct kvm_mmu_page *sp; - kvm_mmu_free_some_pages(vcpu); + make_mmu_pages_available(vcpu); sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache); sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache); @@ -4010,10 +4012,13 @@ int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva) } EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt); -void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu) +static void make_mmu_pages_available(struct kvm_vcpu *vcpu) { LIST_HEAD(invalid_list); + if (likely(kvm_mmu_available_pages(vcpu->kvm) >= KVM_MIN_FREE_MMU_PAGES)) + return; + while (kvm_mmu_available_pages(vcpu->kvm) < KVM_REFILL_PAGES) { if (!prepare_zap_oldest_mmu_page(vcpu->kvm, &invalid_list)) break; diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index 3b1ad0049ea4..2adcbc2cac6d 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -64,12 +64,6 @@ static inline unsigned int kvm_mmu_available_pages(struct kvm *kvm) return 0; } -static inline void kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu) -{ - if (unlikely(kvm_mmu_available_pages(vcpu->kvm)< KVM_MIN_FREE_MMU_PAGES)) - __kvm_mmu_free_some_pages(vcpu); -} - static inline int kvm_mmu_reload(struct kvm_vcpu *vcpu) { if (likely(vcpu->arch.mmu.root_hpa != INVALID_PAGE)) -- cgit v1.2.3