[PATCH] Print a user-friendly message on failed vmentry

Mohammed Gamal
2010-05-20T02:27:47Z

This patch address bug report in https://bugs.launchpad.net/qemu/+bug/530077.

Failed vmentries were handled with handle_unhandled() which prints a rather
unfriendly message to the user. This patch separates handling vmentry failures
from unknown exit reasons and prints a friendly message to the user.

Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com>
---
qemu-kvm.c | 19 ++++++++++++++++++-
1 files changed, 18 insertions(+), 1 deletions(-)

diff --git a/qemu-kvm.c b/qemu-kvm.c
index 35a4c8a..1fdb6fe 100644
--- a/qemu-kvm.c
+++ b/qemu-kvm.c
@@ -106,6 +106,23 @@ static int handle_unhandled(uint64_t reason)
return -EINVAL;
}

+static int handle_failed_vmentry(uint64_t reason)
+{
+ fprintf(stderr, "kvm: vm entry failed with error 0x%" PRIx64 "\n\n", reason);
+ fprintf(stderr, "If you're runnning a guest on an Intel machine without\n");
+ fprintf(stderr, "unrestricted mode support, the failure can be most likely\n");
+ fprintf(stderr, "due to the guest entering an invalid state for Intel VT.\n");
+ fprintf(stderr, "For example, the guest maybe running in big real mode\n");
+ fprintf(stderr, "which is not supported on less recent Intel processors.\n\n");
+ fprintf(stderr, "You may want to try enabling KVM real mode emulation. To\n");
+ fprintf(stderr, "enable it, you can run the following commands as root:\n");
+ fprintf(stderr, "# rmmod kvm_intel\n");
+ fprintf(stderr, "# rmmod kvm\n");
+ fprintf(stderr, "# modprobe kvm_intel emulate_invalid_guest_state=1\n\n");
+ fprintf(stderr, "WARNING: Real mode emulation is still work-in-progress\n");
+ fprintf(stderr, "and thus it is not always guaranteed to work.\n\n");
+ return -EINVAL;
+}

static inline void set_gsi(kvm_context_t kvm, unsigned int gsi)
{
@@ -586,7 +603,7 @@ int kvm_run(CPUState *env)
r = handle_unhandled(run->hw.hardware_exit_reason);
break;
case KVM_EXIT_FAIL_ENTRY:
- r = handle_unhandled(run->fail_entry.hardware_entry_failure_reason);
+ r = handle_failed_vmentry(run->fail_entry.hardware_entry_failure_reason);
break;
case KVM_EXIT_EXCEPTION:
fprintf(stderr, "exception %d (%x)\n", run->ex.exception,
--
1.7.0.4