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| author | Junaid Shahid <junaids@google.com> | 2018-06-27 14:59:04 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2018-08-06 17:58:49 +0200 |
| commit | 5ce4786f75d16504223c7a65a42b200c2550fa29 (patch) | |
| tree | eee73cd1d96eaf252c36eae05b55991c4511885a /arch/x86/kvm/mmu.c | |
| parent | 42522d08cdba6d8be4247e4f0770f39f4708b71f (diff) | |
| download | lwn-5ce4786f75d16504223c7a65a42b200c2550fa29.tar.gz lwn-5ce4786f75d16504223c7a65a42b200c2550fa29.zip | |
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 <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu.c')
| -rw-r--r-- | arch/x86/kvm/mmu.c | 16 |
1 files changed, 12 insertions, 4 deletions
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; |