KVM: SVM: copy instruction bytes from VMCB

In case of a nested page fault or an intercepted #PF newer SVM
implementations provide a copy of the faulting instruction bytes
in the VMCB.
Use these bytes to feed the instruction emulator and avoid the costly
guest instruction fetch in this case.

Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a6fcb76196b7..7ad9cda8ff36 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4365,7 +4365,9 @@ static bool reexecute_instruction(struct kvm_vcpu *vcpu, gva_t gva)
 
 int x86_emulate_instruction(struct kvm_vcpu *vcpu,
                             unsigned long cr2,
-                            int emulation_type)
+                            int emulation_type,
+                            void *insn,
+                            int insn_len)
 {
         int r;
         struct decode_cache *c = &vcpu->arch.emulate_ctxt.decode;
@@ -4386,7 +4388,7 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu,
                 vcpu->arch.emulate_ctxt.have_exception = false;
                 vcpu->arch.emulate_ctxt.perm_ok = false;
 
-                r = x86_decode_insn(&vcpu->arch.emulate_ctxt);
+                r = x86_decode_insn(&vcpu->arch.emulate_ctxt, insn, insn_len);
                 if (r == X86EMUL_PROPAGATE_FAULT)
                         goto done;