KVM: MMU: retry #PF for softmmu

Retry #PF for softmmu only when the current vcpu has the same cr3 as the time
when #PF occurs

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

4 files changed, 17 insertions, 6 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index aa1518d794cc..4461429957a9 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -593,6 +593,7 @@ struct kvm_x86_ops {
 struct kvm_arch_async_pf {
         u32 token;
         gfn_t gfn;
+        unsigned long cr3;
         bool direct_map;
 };
 
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index d475b6b87dce..abda57fac659 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2608,9 +2608,11 @@ static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
 static int kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn)
 {
         struct kvm_arch_async_pf arch;
+
         arch.token = (vcpu->arch.apf.id++ << 12) | vcpu->vcpu_id;
         arch.gfn = gfn;
         arch.direct_map = vcpu->arch.mmu.direct_map;
+        arch.cr3 = vcpu->arch.mmu.get_cr3(vcpu);
 
         return kvm_setup_async_pf(vcpu, gva, gfn, &arch);
 }
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 52b3e91918c6..146b681e6ab0 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -438,7 +438,8 @@ static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, struct guest_walker *gw,
 static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
                          struct guest_walker *gw,
                          int user_fault, int write_fault, int hlevel,
-                         int *ptwrite, pfn_t pfn, bool map_writable)
+                         int *ptwrite, pfn_t pfn, bool map_writable,
+                         bool prefault)
 {
         unsigned access = gw->pt_access;
         struct kvm_mmu_page *sp = NULL;
@@ -512,7 +513,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
 
         mmu_set_spte(vcpu, it.sptep, access, gw->pte_access & access,
                      user_fault, write_fault, dirty, ptwrite, it.level,
-                     gw->gfn, pfn, false, map_writable);
+                     gw->gfn, pfn, prefault, map_writable);
         FNAME(pte_prefetch)(vcpu, gw, it.sptep);
 
         return it.sptep;
@@ -568,8 +569,11 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
          */
         if (!r) {
                 pgprintk("%s: guest page fault\n", __func__);
-                inject_page_fault(vcpu, &walker.fault);
-                vcpu->arch.last_pt_write_count = 0; /* reset fork detector */
+                if (!prefault) {
+                        inject_page_fault(vcpu, &walker.fault);
+                        /* reset fork detector */
+                        vcpu->arch.last_pt_write_count = 0;
+                }
                 return 0;
         }
 
@@ -599,7 +603,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
         trace_kvm_mmu_audit(vcpu, AUDIT_PRE_PAGE_FAULT);
         kvm_mmu_free_some_pages(vcpu);
         sptep = FNAME(fetch)(vcpu, addr, &walker, user_fault, write_fault,
-                             level, &write_pt, pfn, map_writable);
+                             level, &write_pt, pfn, map_writable, prefault);
         (void)sptep;
         pgprintk("%s: shadow pte %p %llx ptwrite %d\n", __func__,
                  sptep, *sptep, write_pt);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8b4d5fc08012..cd71d210c409 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6182,7 +6182,7 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
 {
         int r;
 
-        if (!vcpu->arch.mmu.direct_map || !work->arch.direct_map ||
+        if ((vcpu->arch.mmu.direct_map != work->arch.direct_map) ||
               is_error_page(work->page))
                 return;
 
@@ -6190,6 +6190,10 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
         if (unlikely(r))
                 return;
 
+        if (!vcpu->arch.mmu.direct_map &&
+              work->arch.cr3 != vcpu->arch.mmu.get_cr3(vcpu))
+                return;
+
         vcpu->arch.mmu.page_fault(vcpu, work->gva, 0, true);
 }