[PATCH kvmtool 2/2] cpu: vmexit: Handle KVM_EXIT_MEMORY_FAULT correctly

["Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>]

Linux kernel documentation states:

"Note! KVM_EXIT_MEMORY_FAULT is unique among all KVM exit reasons in
that it accompanies a return code of '-1', not '0'! errno will always be
set to EFAULT or EHWPOISON when KVM exits with KVM_EXIT_MEMORY_FAULT,
userspace should assume kvm_run.exit_reason is stale/undefined for all
other error numbers." "

Update the KVM_RUN ioctl error handling to correctly handle
KVM_EXIT_MEMORY_FAULT.

Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
 kvm-cpu.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/kvm-cpu.c b/kvm-cpu.c
index 66e30ba54e26..40e4efc33a1d 100644
--- a/kvm-cpu.c
+++ b/kvm-cpu.c
@@ -41,8 +41,15 @@ void kvm_cpu__run(struct kvm_cpu *vcpu)
 		return;
 
 	err = ioctl(vcpu->vcpu_fd, KVM_RUN, 0);
-	if (err < 0 && (errno != EINTR && errno != EAGAIN))
-		die_perror("KVM_RUN failed");
+	if (err < 0) {
+		if (errno == EINTR || errno == EAGAIN)
+			return;
+		else if (errno == EFAULT &&
+			 vcpu->kvm_run->exit_reason == KVM_EXIT_MEMORY_FAULT)
+			return;
+		else
+			die_perror("KVM_RUN failed");
+	}
 }
 
 static void kvm_cpu_signal_handler(int signum)
-- 
2.43.0