[PATCH 1/2] KVM: x86: Return emulator error if RDMSR/WRMSR emulation failed

["Hou Wenlong" <houwenlong.hwl@antgroup.com>]

The return value of emulator_{get|set}_mst_with_filter()
is confused, since msr access error and emulator error
are mixed. Although, KVM_MSR_RET_* doesn't conflict with
X86EMUL_IO_NEEDED at present, it is better to convert
msr access error to emulator error if error value is
needed.

Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
---
 arch/x86/kvm/x86.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5366f884e9a7..8df89b9c212f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7908,11 +7908,12 @@ static int emulator_get_msr_with_filter(struct x86_emulate_ctxt *ctxt,
 	int r;
 
 	r = kvm_get_msr_with_filter(vcpu, msr_index, pdata);
-
-	if (r && kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_RDMSR, 0,
-				    complete_emulated_rdmsr, r)) {
-		/* Bounce to user space */
-		return X86EMUL_IO_NEEDED;
+	if (r) {
+		if (kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_RDMSR, 0,
+				       complete_emulated_rdmsr, r))
+			r = X86EMUL_IO_NEEDED;
+		else
+			r = X86EMUL_UNHANDLEABLE;
 	}
 
 	return r;
@@ -7925,11 +7926,12 @@ static int emulator_set_msr_with_filter(struct x86_emulate_ctxt *ctxt,
 	int r;
 
 	r = kvm_set_msr_with_filter(vcpu, msr_index, data);
-
-	if (r && kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_WRMSR, data,
-				    complete_emulated_msr_access, r)) {
-		/* Bounce to user space */
-		return X86EMUL_IO_NEEDED;
+	if (r > 0) {
+		if (kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_WRMSR, data,
+				       complete_emulated_msr_access, r))
+			r = X86EMUL_IO_NEEDED;
+		else
+			r = X86EMUL_UNHANDLEABLE;
 	}
 
 	return r;
-- 
2.31.1