[Qemu-devel] RE: [PATCH] hw/ivshmem.c don't check for negative values on unsigned data types

[Hao, Xudong]

address@hidden wrote:
> From: Jes Sorensen <address@hidden>
> 
> There is no need to check for dest < 0 or vector >= 0 as both are
> uint16_t.
> 
> This should fix problems with broken build with aggressive compiler
> flags. Reported by Xudong Hao <address@hidden>
> 
> Signed-off-by: Jes Sorensen <address@hidden>
> ---
>  hw/ivshmem.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/ivshmem.c b/hw/ivshmem.c
> index bbb5cba..afebbc3 100644
> --- a/hw/ivshmem.c
> +++ b/hw/ivshmem.c
> @@ -199,13 +199,13 @@ static void ivshmem_io_writel(void *opaque,
> target_phys_addr_t addr, 
> 
>          case DOORBELL:
>              /* check that dest VM ID is reasonable */
> -            if ((dest < 0) || (dest > s->max_peer)) {
> +            if (dest > s->max_peer) {
>                  IVSHMEM_DPRINTF("Invalid destination VM ID (%d)\n",
>                  dest); break;
>              }
> 
>              /* check doorbell range */
> -            if ((vector >= 0) && (vector <
> s->peers[dest].nb_eventfds)) { +            if (vector <
>                  s->peers[dest].nb_eventfds) {
>                                                     
>                  IVSHMEM_DPRINTF("Writing %" PRId64 " to VM %d on
> vector %d\n", write_one, dest, vector); if
> (write(s->peers[dest].eventfds[vector],  

This patch works for me.


Thanks,
Xudong