Use the host CPU's native hypercall instruction, i.e. VMCALL vs. VMMCALL,
in kvm_hypercall(), as relying on KVM to patch in the native hypercall on
a #UD for the "wrong" hypercall requires KVM_X86_QUIRK_FIX_HYPERCALL_INSN
to be enabled and flat out doesn't work if guest memory is encrypted with
a private key, e.g. for SEV VMs.
Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Reviewed-by: David Matlack <dmatlack@xxxxxxxxxx>
Signed-off-by: Vishal Annapurve <vannapurve@xxxxxxxxxx>
---
tools/testing/selftests/kvm/lib/x86_64/processor.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index 84915bc7d689..ae1e573d94ce 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -1144,9 +1144,15 @@ uint64_t kvm_hypercall(uint64_t nr, uint64_t a0, uint64_t a1, uint64_t a2,
{
uint64_t r;
- asm volatile("vmcall"
+ asm volatile("test %[use_vmmcall], %[use_vmmcall]\n\t"
+ "jnz 1f\n\t"
+ "vmcall\n\t"
+ "jmp 2f\n\t"
+ "1: vmmcall\n\t"
+ "2:"
: "=a"(r)
- : "a"(nr), "b"(a0), "c"(a1), "d"(a2), "S"(a3));
+ : "a"(nr), "b"(a0), "c"(a1), "d"(a2), "S"(a3),
+ [use_vmmcall] "r" (host_cpu_is_amd));
return r;
}
--
2.39.0.314.g84b9a713c41-goog
