[PATCH v5 1/4] KVM: x86: Clarify the kvm_run.emulation_failure structure layout

From: David Edmondson
Date: Thu Sep 16 2021 - 04:32:49 EST


Until more flags for kvm_run.emulation_failure flags are defined, it
is undetermined whether new payload elements corresponding to those
flags will be additive or alternative. As a hint to userspace that an
alternative is possible, wrap the current payload elements in a union.

Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: David Edmondson <david.edmondson@xxxxxxxxxx>
---
include/uapi/linux/kvm.h | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index a067410ebea5..8618fe973215 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -402,8 +402,12 @@ struct kvm_run {
__u32 suberror;
__u32 ndata;
__u64 flags;
- __u8 insn_size;
- __u8 insn_bytes[15];
+ union {
+ struct {
+ __u8 insn_size;
+ __u8 insn_bytes[15];
+ };
+ };
} emulation_failure;
/* KVM_EXIT_OSI */
struct {
--
2.33.0