From 5ce4786f75d16504223c7a65a42b200c2550fa29 Mon Sep 17 00:00:00 2001 From: Junaid Shahid Date: Wed, 27 Jun 2018 14:59:04 -0700 Subject: kvm: x86: Make sync_page() flush remote TLBs once only sync_page() calls set_spte() from a loop across a page table. It would work better if set_spte() left the TLB flushing to its callers, so that sync_page() can aggregate into a single call. Signed-off-by: Junaid Shahid Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu.c | 16 ++++++++++++---- arch/x86/kvm/paging_tmpl.h | 12 ++++++++---- 2 files changed, 20 insertions(+), 8 deletions(-) (limited to 'arch') diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index d594690d8b95..75bc73e23df0 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2724,6 +2724,10 @@ static bool kvm_is_mmio_pfn(kvm_pfn_t pfn) return true; } +/* Bits which may be returned by set_spte() */ +#define SET_SPTE_WRITE_PROTECTED_PT BIT(0) +#define SET_SPTE_NEED_REMOTE_TLB_FLUSH BIT(1) + static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access, int level, gfn_t gfn, kvm_pfn_t pfn, bool speculative, @@ -2800,7 +2804,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, if (mmu_need_write_protect(vcpu, gfn, can_unsync)) { pgprintk("%s: found shadow page for %llx, marking ro\n", __func__, gfn); - ret = 1; + ret |= SET_SPTE_WRITE_PROTECTED_PT; pte_access &= ~ACC_WRITE_MASK; spte &= ~(PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE); } @@ -2816,7 +2820,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, set_pte: if (mmu_spte_update(sptep, spte)) - kvm_flush_remote_tlbs(vcpu->kvm); + ret |= SET_SPTE_NEED_REMOTE_TLB_FLUSH; done: return ret; } @@ -2827,6 +2831,7 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access, { int was_rmapped = 0; int rmap_count; + int set_spte_ret; int ret = RET_PF_RETRY; pgprintk("%s: spte %llx write_fault %d gfn %llx\n", __func__, @@ -2854,12 +2859,15 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access, was_rmapped = 1; } - if (set_spte(vcpu, sptep, pte_access, level, gfn, pfn, speculative, - true, host_writable)) { + set_spte_ret = set_spte(vcpu, sptep, pte_access, level, gfn, pfn, + speculative, true, host_writable); + if (set_spte_ret & SET_SPTE_WRITE_PROTECTED_PT) { if (write_fault) ret = RET_PF_EMULATE; kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu); } + if (set_spte_ret & SET_SPTE_NEED_REMOTE_TLB_FLUSH) + kvm_flush_remote_tlbs(vcpu->kvm); if (unlikely(is_mmio_spte(*sptep))) ret = RET_PF_EMULATE; diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 74996fc2fc97..208f7646ce0d 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -968,6 +968,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) int i, nr_present = 0; bool host_writable; gpa_t first_pte_gpa; + int set_spte_ret = 0; /* direct kvm_mmu_page can not be unsync. */ BUG_ON(sp->role.direct); @@ -1024,12 +1025,15 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) host_writable = sp->spt[i] & SPTE_HOST_WRITEABLE; - set_spte(vcpu, &sp->spt[i], pte_access, - PT_PAGE_TABLE_LEVEL, gfn, - spte_to_pfn(sp->spt[i]), true, false, - host_writable); + set_spte_ret |= set_spte(vcpu, &sp->spt[i], + pte_access, PT_PAGE_TABLE_LEVEL, + gfn, spte_to_pfn(sp->spt[i]), + true, false, host_writable); } + if (set_spte_ret & SET_SPTE_NEED_REMOTE_TLB_FLUSH) + kvm_flush_remote_tlbs(vcpu->kvm); + return nr_present; } -- cgit v1.2.3