On 28/04/2025 12:57, Aneesh Kumar K.V (Arm) wrote:
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 KVM_RUN ioctl error handling to correctly handle
KVM_EXIT_MEMORY_FAULT. This enables the memory fault exit handlers in
the kernel to return -EFAULT as the return value. VMM support is
still required to handle these memory fault exits, but that is not
included in this change
Reviewed-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@xxxxxxxxxx>
---
kvm-cpu.c | 15 +++++++++++++--
kvm.c | 1 +
2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/kvm-cpu.c b/kvm-cpu.c
index 7362f2e99261..40041a22b3fe 100644
--- a/kvm-cpu.c
+++ b/kvm-cpu.c
@@ -43,8 +43,19 @@ 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) {
+ switch (errno) {
+ case EINTR:
+ case EAGAIN:
+ return;
+ case EFAULT:
Do we need to handle EHWPOISON too, as per the API ?
Suzuki
+ if (vcpu->kvm_run->exit_reason == KVM_EXIT_MEMORY_FAULT)
+ return;
+ /* fallthrough */
+ default:
+ die_perror("KVM_RUN failed");
+ }
+ }
}
static void kvm_cpu_signal_handler(int signum)
diff --git a/kvm.c b/kvm.c
index 07089cf1b332..b6375a114d11 100644
--- a/kvm.c
+++ b/kvm.c
@@ -55,6 +55,7 @@ const char *kvm_exit_reasons[] = {
#ifdef CONFIG_PPC64
DEFINE_KVM_EXIT_REASON(KVM_EXIT_PAPR_HCALL),
#endif
+ DEFINE_KVM_EXIT_REASON(KVM_EXIT_MEMORY_FAULT),
};
static int pause_event;
