KVM: Fix mov cr3 #GP at wrong instruction

On Intel, we call skip_emulated_instruction() even if we injected a #GP,
resulting in the #GP pointing at the wrong address.

Fix by injecting the exception and skipping the instruction at the same place,
so we can do just one or the other.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

5 files changed, 8 insertions, 14 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index ea8c319cdffc..c2813d658f3e 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -598,7 +598,7 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason,
                     bool has_error_code, u32 error_code);
 
 int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0);
-void kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3);
+int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3);
 int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4);
 void kvm_set_cr8(struct kvm_vcpu *vcpu, unsigned long cr8);
 int kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val);
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 4706a936e36f..aa98fca03ed7 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3203,7 +3203,7 @@ static int kvm_pv_mmu_write(struct kvm_vcpu *vcpu,
 
 static int kvm_pv_mmu_flush_tlb(struct kvm_vcpu *vcpu)
 {
-        kvm_set_cr3(vcpu, vcpu->arch.cr3);
+        (void)kvm_set_cr3(vcpu, vcpu->arch.cr3);
         return 1;
 }
 
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 6d1616d47c54..f7a6fdcf8ef3 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1963,7 +1963,7 @@ static int nested_svm_vmexit(struct vcpu_svm *svm)
                 svm->vmcb->save.cr3 = hsave->save.cr3;
                 svm->vcpu.arch.cr3 = hsave->save.cr3;
         } else {
-                kvm_set_cr3(&svm->vcpu, hsave->save.cr3);
+                (void)kvm_set_cr3(&svm->vcpu, hsave->save.cr3);
         }
         kvm_register_write(&svm->vcpu, VCPU_REGS_RAX, hsave->save.rax);
         kvm_register_write(&svm->vcpu, VCPU_REGS_RSP, hsave->save.rsp);
@@ -2086,7 +2086,7 @@ static bool nested_svm_vmrun(struct vcpu_svm *svm)
                 svm->vmcb->save.cr3 = nested_vmcb->save.cr3;
                 svm->vcpu.arch.cr3 = nested_vmcb->save.cr3;
         } else
-                kvm_set_cr3(&svm->vcpu, nested_vmcb->save.cr3);
+                (void)kvm_set_cr3(&svm->vcpu, nested_vmcb->save.cr3);
 
         /* Guest paging mode is active - reset mmu */
         kvm_mmu_reset_context(&svm->vcpu);
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f64d65dc38c6..345a35470511 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3185,8 +3185,8 @@ static int handle_cr(struct kvm_vcpu *vcpu)
                         complete_insn_gp(vcpu, err);
                         return 1;
                 case 3:
-                        kvm_set_cr3(vcpu, val);
-                        skip_emulated_instruction(vcpu);
+                        err = kvm_set_cr3(vcpu, val);
+                        complete_insn_gp(vcpu, err);
                         return 1;
                 case 4:
                         err = kvm_set_cr4(vcpu, val);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ed3af15d4404..795999e1ac19 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -565,7 +565,7 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 }
 EXPORT_SYMBOL_GPL(kvm_set_cr4);
 
-static int __kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
+int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
 {
         if (cr3 == vcpu->arch.cr3 && !pdptrs_changed(vcpu)) {
                 kvm_mmu_sync_roots(vcpu);
@@ -604,12 +604,6 @@ static int __kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
         vcpu->arch.mmu.new_cr3(vcpu);
         return 0;
 }
-
-void kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
-{
-        if (__kvm_set_cr3(vcpu, cr3))
-                kvm_inject_gp(vcpu, 0);
-}
 EXPORT_SYMBOL_GPL(kvm_set_cr3);
 
 int __kvm_set_cr8(struct kvm_vcpu *vcpu, unsigned long cr8)
@@ -3726,7 +3720,7 @@ static int emulator_set_cr(int cr, unsigned long val, struct kvm_vcpu *vcpu)
                 vcpu->arch.cr2 = val;
                 break;
         case 3:
-                res = __kvm_set_cr3(vcpu, val);
+                res = kvm_set_cr3(vcpu, val);
                 break;
         case 4:
                 res = kvm_set_cr4(vcpu, mk_cr_64(kvm_read_cr4(vcpu), val));