kvm: x86: Add "last CPU" to some KVM_EXIT information
More often than not, a failed VM-entry in an x86 production
environment is induced by a defective CPU. To help identify the bad
hardware, include the id of the last logical CPU to run a vCPU in the
information provided to userspace on a KVM exit for failed VM-entry or
for KVM internal errors not associated with emulation. The presence of
this additional information is indicated by a new capability,
KVM_CAP_LAST_CPU.
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Oliver Upton <oupton@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Message-Id: <20200603235623.245638-5-jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 426f945..1cfe79b 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -4794,6 +4794,7 @@
/* KVM_EXIT_FAIL_ENTRY */
struct {
__u64 hardware_entry_failure_reason;
+ __u32 cpu; /* if KVM_LAST_CPU */
} fail_entry;
If exit_reason is KVM_EXIT_FAIL_ENTRY, the vcpu could not be run due