KVM: MMU: Propagate the right fault back to the guest after gva_to_gpa

This patch implements logic to make sure that either a
page-fault/page-fault-vmexit or a nested-page-fault-vmexit
is propagated back to the guest.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

2 files changed, 18 insertions, 1 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 08bc383083ff..574db6d1532a 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -660,6 +660,7 @@ void kvm_inject_page_fault(struct kvm_vcpu *vcpu);
 int kvm_read_guest_page_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
                             gfn_t gfn, void *data, int offset, int len,
                             u32 access);
+void kvm_propagate_fault(struct kvm_vcpu *vcpu);
 bool kvm_require_cpl(struct kvm_vcpu *vcpu, int required_cpl);
 
 int kvm_pic_set_irq(void *opaque, int irq, int level);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e4c76bf86081..0281d920e9ed 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -338,6 +338,22 @@ void kvm_inject_page_fault(struct kvm_vcpu *vcpu)
         kvm_queue_exception_e(vcpu, PF_VECTOR, error_code);
 }
 
+void kvm_propagate_fault(struct kvm_vcpu *vcpu)
+{
+        u32 nested, error;
+
+        error   = vcpu->arch.fault.error_code;
+        nested  = error &  PFERR_NESTED_MASK;
+        error   = error & ~PFERR_NESTED_MASK;
+
+        vcpu->arch.fault.error_code = error;
+
+        if (mmu_is_nested(vcpu) && !nested)
+                vcpu->arch.nested_mmu.inject_page_fault(vcpu);
+        else
+                vcpu->arch.mmu.inject_page_fault(vcpu);
+}
+
 void kvm_inject_nmi(struct kvm_vcpu *vcpu)
 {
         vcpu->arch.nmi_pending = 1;
@@ -4140,7 +4156,7 @@ static void inject_emulated_exception(struct kvm_vcpu *vcpu)
 {
         struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
         if (ctxt->exception == PF_VECTOR)
-                kvm_inject_page_fault(vcpu);
+                kvm_propagate_fault(vcpu);
         else if (ctxt->error_code_valid)
                 kvm_queue_exception_e(vcpu, ctxt->exception, ctxt->error_code);
         else