KVM: fix tracing kvm_try_async_get_page

[karo-tx-linux.git] / arch / x86 / kvm / mmu.c

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 11b9102f411345349c645bbefc8be942dcd6f07b..272e3020003043a8add639d123675e7b0d507caf 100644 (file)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2069,6 +2069,16 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
                                 spte_to_pfn(*sptep), pfn);
                        drop_spte(vcpu->kvm, sptep, shadow_trap_nonpresent_pte);
                        kvm_flush_remote_tlbs(vcpu->kvm);
+               /*
+                * If we overwrite a writable spte with a read-only one,
+                * drop it and 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.
+                */
+               } else if (is_writable_pte(*sptep) &&
+                         (!(pte_access & ACC_WRITE_MASK) || !dirty)) {
+                       drop_spte(vcpu->kvm, sptep, shadow_trap_nonpresent_pte);
+                       kvm_flush_remote_tlbs(vcpu->kvm);
                } else
                        was_rmapped = 1;
        }
@@ -2206,7 +2216,7 @@ static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep)
 }
 
 static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
-                       int level, gfn_t gfn, pfn_t pfn)
+                       int map_writable, int level, gfn_t gfn, pfn_t pfn)
 {
        struct kvm_shadow_walk_iterator iterator;
        struct kvm_mmu_page *sp;
@@ -2215,9 +2225,13 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
 
        for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
                if (iterator.level == level) {
-                       mmu_set_spte(vcpu, iterator.sptep, ACC_ALL, ACC_ALL,
+                       unsigned pte_access = ACC_ALL;
+
+                       if (!map_writable)
+                               pte_access &= ~ACC_WRITE_MASK;
+                       mmu_set_spte(vcpu, iterator.sptep, ACC_ALL, pte_access,
                                     0, write, 1, &pt_write,
-                                    level, gfn, pfn, false, true);
+                                    level, gfn, pfn, false, map_writable);
                        direct_pte_prefetch(vcpu, iterator.sptep);
                        ++vcpu->stat.pf_fixed;
                        break;
@@ -2278,6 +2292,7 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
        int level;
        pfn_t pfn;
        unsigned long mmu_seq;
+       bool map_writable;
 
        level = mapping_level(vcpu, gfn);
 
@@ -2292,7 +2307,7 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
 
        mmu_seq = vcpu->kvm->mmu_notifier_seq;
        smp_rmb();
-       pfn = gfn_to_pfn(vcpu->kvm, gfn);
+       pfn = gfn_to_pfn_prot(vcpu->kvm, gfn, write, &map_writable);
 
        /* mmio */
        if (is_error_pfn(pfn))
@@ -2302,7 +2317,7 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
        if (mmu_notifier_retry(vcpu, mmu_seq))
                goto out_unlock;
        kvm_mmu_free_some_pages(vcpu);
-       r = __direct_map(vcpu, v, write, level, gfn, pfn);
+       r = __direct_map(vcpu, v, write, map_writable, level, gfn, pfn);
        spin_unlock(&vcpu->kvm->mmu_lock);
 
 
@@ -2601,11 +2616,11 @@ static bool can_do_async_pf(struct kvm_vcpu *vcpu)
 }
 
 static bool try_async_pf(struct kvm_vcpu *vcpu, bool no_apf, gfn_t gfn,
-                        gva_t gva, pfn_t *pfn)
+                        gva_t gva, pfn_t *pfn, bool write, bool *writable)
 {
        bool async;
 
-       *pfn = gfn_to_pfn_async(vcpu->kvm, gfn, &async);
+       *pfn = gfn_to_pfn_async(vcpu->kvm, gfn, &async, write, writable);
 
        if (!async)
                return false; /* *pfn has correct page already */
@@ -2613,7 +2628,7 @@ static bool try_async_pf(struct kvm_vcpu *vcpu, bool no_apf, gfn_t gfn,
        put_page(pfn_to_page(*pfn));
 
        if (!no_apf && can_do_async_pf(vcpu)) {
-               trace_kvm_try_async_get_page(async, *pfn);
+               trace_kvm_try_async_get_page(gva, gfn);
                if (kvm_find_async_pf_gfn(vcpu, gfn)) {
                        trace_kvm_async_pf_doublefault(gva, gfn);
                        kvm_make_request(KVM_REQ_APF_HALT, vcpu);
@@ -2622,7 +2637,7 @@ static bool try_async_pf(struct kvm_vcpu *vcpu, bool no_apf, gfn_t gfn,
                        return true;
        }
 
-       *pfn = gfn_to_pfn(vcpu->kvm, gfn);
+       *pfn = gfn_to_pfn_prot(vcpu->kvm, gfn, write, writable);
 
        return false;
 }
@@ -2635,6 +2650,8 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
        int level;
        gfn_t gfn = gpa >> PAGE_SHIFT;
        unsigned long mmu_seq;
+       int write = error_code & PFERR_WRITE_MASK;
+       bool map_writable;
 
        ASSERT(vcpu);
        ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
@@ -2650,7 +2667,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
        mmu_seq = vcpu->kvm->mmu_notifier_seq;
        smp_rmb();
 
-       if (try_async_pf(vcpu, no_apf, gfn, gpa, &pfn))
+       if (try_async_pf(vcpu, no_apf, gfn, gpa, &pfn, write, &map_writable))
                return 0;
 
        /* mmio */
@@ -2660,7 +2677,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
        if (mmu_notifier_retry(vcpu, mmu_seq))
                goto out_unlock;
        kvm_mmu_free_some_pages(vcpu);
-       r = __direct_map(vcpu, gpa, error_code & PFERR_WRITE_MASK,
+       r = __direct_map(vcpu, gpa, write, map_writable,
                         level, gfn, pfn);
        spin_unlock(&vcpu->kvm->mmu_lock);