It depends on PTE_LIST_WRITE_PROTECT bit in rmap which let us quickly know whether the page is writable out of mmu-lock
Signed-off-by: Xiao Guangrong <[email protected]> --- arch/x86/kvm/mmu.c | 17 +++++++++++++---- arch/x86/kvm/paging_tmpl.h | 2 +- 2 files changed, 14 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 3887a07..c029185 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -1148,6 +1148,12 @@ static int rmap_write_protect(struct kvm *kvm, u64 gfn) *rmapp |= PTE_LIST_WRITE_PROTECT; + /* + * Setting PTE_LIST_WRITE_PROTECT bit before doing page + * write-protect. + */ + smp_mb(); + write_protected |= __rmap_write_protect(kvm, rmapp, PT_PAGE_TABLE_LEVEL); @@ -2264,7 +2270,7 @@ static void kvm_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn) } static int mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn, - bool can_unsync) + bool can_unsync, bool unlock) { struct kvm_mmu_page *s; struct hlist_node *node; @@ -2278,6 +2284,9 @@ static int mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn, if (!(*rmap & PTE_LIST_WRITE_PROTECT)) return 0; + if (unlock) + return 1; + for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node) { if (!can_unsync) return 1; @@ -2301,7 +2310,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access, int user_fault, int write_fault, int level, gfn_t gfn, pfn_t pfn, bool speculative, - bool can_unsync, bool host_writable) + bool can_unsync, bool host_writable, bool unlock) { u64 spte, entry = *sptep; int ret = 0; @@ -2367,7 +2376,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, if (!can_unsync && is_writable_pte(*sptep)) goto set_pte; - if (mmu_need_write_protect(vcpu, gfn, can_unsync)) { + if (mmu_need_write_protect(vcpu, gfn, can_unsync, unlock)) { pgprintk("%s: found shadow page for %llx, marking ro\n", __func__, gfn); ret = 1; @@ -2433,7 +2442,7 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, if (set_spte(vcpu, sptep, pte_access, user_fault, write_fault, level, gfn, pfn, speculative, true, - host_writable)) { + host_writable, false)) { if (write_fault) *emulate = 1; kvm_mmu_flush_tlb(vcpu); diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index f0fbde3..e2af5a5 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -820,7 +820,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) set_spte(vcpu, &sp->spt[i], pte_access, 0, 0, PT_PAGE_TABLE_LEVEL, gfn, spte_to_pfn(sp->spt[i]), true, false, - host_writable); + host_writable, false); } return !nr_present; -- 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
