Re: [Qemu-devel] [PATCH] scsi: pvscsi: request descriptor data_length to 32 bit

[Paolo Bonzini]

On 05/09/2016 14:58, P J P wrote:
> +-- On Mon, 5 Sep 2016, Paolo Bonzini wrote --+
> | Without a public spec it's hard, but I guess 2048 is more than enough.
> 
> ===
> diff --git a/hw/scsi/vmw_pvscsi.c b/hw/scsi/vmw_pvscsi.c
> index 4245c15..4823b9d 100644
> --- a/hw/scsi/vmw_pvscsi.c
> +++ b/hw/scsi/vmw_pvscsi.c
> @@ -628,17 +628,16 @@ pvscsi_queue_pending_descriptor(PVSCSIState *s, 
> SCSIDevice **d,
>  static void
>  pvscsi_convert_sglist(PVSCSIRequest *r)
>  {
> -    int chunk_size;
> +    int chunk_size, n = 0;

chunk_size should be uint32_t.

>      uint64_t data_length = r->req.dataLen;
>      PVSCSISGState sg = r->sg;
> -    while (data_length) {
> -        while (!sg.resid) {
> +    while (data_length && n < 2048) {
> +        while (!sg.resid && n++ < 2048) {
>              pvscsi_get_next_sg_elem(&sg);
>              trace_pvscsi_convert_sglist(r->req.context, r->sg.dataAddr,
>                                          r->sg.resid);
>          }
> -        assert(data_length > 0);
> -        chunk_size = MIN((unsigned) data_length, sg.resid);
> +        chunk_size = MIN(data_length, sg.resid);
>          if (chunk_size) {
>              qemu_sglist_add(&r->sgl, sg.dataAddr, chunk_size);
>          }
> ===
> 
> Does this look okay?

Yes, just change 2048 to a #define PVSCSI_MAX_SG_ELEM.

Paolo

> --
> Prasad J Pandit / Red Hat Product Security Team
> 47AF CE69 3A90 54AA 9045 1053 DD13 3D32 FE5B 041F
>