On 13/11/2025 5:24 pm, Roger Pau Monne wrote:
> diff --git a/xen/arch/x86/hvm/viridian/synic.c
> b/xen/arch/x86/hvm/viridian/synic.c
> index e6cba7548f1b..6d7b6bd0eda2 100644
> --- a/xen/arch/x86/hvm/viridian/synic.c
> +++ b/xen/arch/x86/hvm/viridian/synic.c
> @@ -327,15 +327,10 @@ bool viridian_synic_deliver_timer_msg(struct vcpu *v,
> unsigned int sintx,
> struct viridian_vcpu *vv = v->arch.hvm.viridian;
> const union hv_synic_sint *vs = &vv->sint[sintx];
> struct hv_message *msg = vv->simp.ptr;
> - struct {
> - uint32_t TimerIndex;
> - uint32_t Reserved;
> - uint64_t ExpirationTime;
> - uint64_t DeliveryTime;
> - } payload = {
> - .TimerIndex = index,
> - .ExpirationTime = expiration,
> - .DeliveryTime = delivery,
> + const struct hv_timer_message_payload payload = {
> + .timer_index = index,
> + .expiration_time = expiration,
> + .delivery_time = delivery,
Align these = for readability?
> };
>
> /* Don't assume SIM page to be mapped. */
> @@ -359,8 +354,8 @@ bool viridian_synic_deliver_timer_msg(struct vcpu *v,
> unsigned int sintx,
> msg->header.message_flags.msg_pending = 0;
> msg->header.payload_size = sizeof(payload);
>
> - BUILD_BUG_ON(sizeof(payload) > sizeof(msg->u.payload));
> - memcpy(msg->u.payload, &payload, sizeof(payload));
> + BUILD_BUG_ON(sizeof(msg->payload.timer) > sizeof(msg->payload.raw));
This BUILD_BUG_ON() was only needed because of the memcpy() between
different types. With structure assignment, the compiler will tell you
if the type mismatches.
Therefore, it's safe to drop.
Otherwise, Reviewed-by: Andrew Cooper <[email protected]>
