Messages in this thread Patch in this message | | | Date | Wed, 23 May 2012 16:53:57 +0800 | From | Xiao Guangrong <> | Subject | [PATCH v5 4/9] KVM: MMU: fold tlb flush judgement into mmu_spte_update |
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mmu_spte_update() is the common function, we can easily audit the path
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> --- arch/x86/kvm/mmu.c | 33 ++++++++++++++++++++------------- 1 files changed, 20 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 337ff0a..4810992 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -478,15 +478,24 @@ static void mmu_spte_set(u64 *sptep, u64 new_spte)
/* Rules for using mmu_spte_update: * Update the state bits, it means the mapped pfn is not changged. + * + * Whenever we overwrite a writable spte with a read-only one we + * should flush remote TLBs. Otherwise rmap_write_protect + * will find a read-only spte, even though the writable spte + * might be cached on a CPU's TLB, the return value indicates this + * case. */ -static void mmu_spte_update(u64 *sptep, u64 new_spte) +static bool mmu_spte_update(u64 *sptep, u64 new_spte) { u64 mask, old_spte = *sptep; + bool ret = false;
WARN_ON(!is_rmap_spte(new_spte));
- if (!is_shadow_present_pte(old_spte)) - return mmu_spte_set(sptep, new_spte); + if (!is_shadow_present_pte(old_spte)) { + mmu_spte_set(sptep, new_spte); + return ret; + }
new_spte |= old_spte & shadow_dirty_mask;
@@ -499,13 +508,18 @@ static void mmu_spte_update(u64 *sptep, u64 new_spte) else old_spte = __update_clear_spte_slow(sptep, new_spte);
+ if (is_writable_pte(old_spte) && !is_writable_pte(new_spte)) + ret = true; + if (!shadow_accessed_mask) - return; + return ret;
if (spte_is_bit_cleared(old_spte, new_spte, shadow_accessed_mask)) kvm_set_pfn_accessed(spte_to_pfn(old_spte)); if (spte_is_bit_cleared(old_spte, new_spte, shadow_dirty_mask)) kvm_set_pfn_dirty(spte_to_pfn(old_spte)); + + return ret; }
/* @@ -2256,7 +2270,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, gfn_t gfn, pfn_t pfn, bool speculative, bool can_unsync, bool host_writable) { - u64 spte, entry = *sptep; + u64 spte; int ret = 0;
if (set_mmio_spte(sptep, gfn, pfn, pte_access)) @@ -2334,14 +2348,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, mark_page_dirty(vcpu->kvm, gfn);
set_pte: - mmu_spte_update(sptep, spte); - /* - * If we overwrite a writable spte with a read-only one we - * should flush remote TLBs. Otherwise rmap_write_protect - * will find a read-only spte, even though the writable spte - * might be cached on a CPU's TLB. - */ - if (is_writable_pte(entry) && !is_writable_pte(*sptep)) + if (mmu_spte_update(sptep, spte)) kvm_flush_remote_tlbs(vcpu->kvm); done: return ret; -- 1.7.7.6
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