On Wed, Mar 04, 2020 at 04:33:11PM +0100, Philippe Mathieu-Daudé wrote:
> The 'union srp_iu' is meant as a pointer to any SRP Information
> Unit type, it is not related to the size of a VIO DMA buffer.
>
> Use a plain buffer for the VIO DMA read/write calls.
> We can remove the reserved buffer from the 'union srp_iu'.
>
> This issue was noticed when replacing the zero-length arrays
> from hw/scsi/srp.h with flexible array member,
> 'clang -fsanitize=undefined' reported:
>
> hw/scsi/spapr_vscsi.c:69:29: error: field 'iu' with variable sized type
> 'union viosrp_iu' not at the end of a struct or class is a GNU extension
> [-Werror,-Wgnu-variable-sized-type-not-at-end]
> union viosrp_iu iu;
> ^
>
> Signed-off-by: Philippe Mathieu-Daudé <phi...@redhat.com>
> ---
> hw/scsi/viosrp.h | 2 +-
> hw/scsi/spapr_vscsi.c | 10 +++++-----
> 2 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/hw/scsi/viosrp.h b/hw/scsi/viosrp.h
> index 25676c2383..aba3203028 100644
> --- a/hw/scsi/viosrp.h
> +++ b/hw/scsi/viosrp.h
> @@ -49,8 +49,8 @@ union srp_iu {
> struct srp_tsk_mgmt tsk_mgmt;
> struct srp_cmd cmd;
> struct srp_rsp rsp;
> - uint8_t reserved[SRP_MAX_IU_LEN];
> };
> +_Static_assert(sizeof(union srp_iu) <= SRP_MAX_IU_LEN, "srp_iu size
> incorrect");
Hrm. Given that srp_iu will be a variably sized type, is this
assertion actually testing anything meaningful?
Otherwise, LGTM.
>
> enum viosrp_crq_formats {
> VIOSRP_SRP_FORMAT = 0x01,
> diff --git a/hw/scsi/spapr_vscsi.c b/hw/scsi/spapr_vscsi.c
> index f1a0bbdc31..f9be68e44e 100644
> --- a/hw/scsi/spapr_vscsi.c
> +++ b/hw/scsi/spapr_vscsi.c
> @@ -66,7 +66,7 @@ typedef union vscsi_crq {
>
> typedef struct vscsi_req {
> vscsi_crq crq;
> - union viosrp_iu iu;
> + uint8_t viosrp_iu_buf[SRP_MAX_IU_LEN];
>
> /* SCSI request tracking */
> SCSIRequest *sreq;
> @@ -99,7 +99,7 @@ typedef struct {
>
> static union viosrp_iu *req_iu(vscsi_req *req)
> {
> - return (union viosrp_iu *)req->iu.srp.reserved;
> + return (union viosrp_iu *)req->viosrp_iu_buf;
> }
>
>
> @@ -184,7 +184,7 @@ static int vscsi_send_iu(VSCSIState *s, vscsi_req *req,
>
> /* First copy the SRP */
> rc = spapr_vio_dma_write(&s->vdev, req->crq.s.IU_data_ptr,
> - &req->iu, length);
> + &req->viosrp_iu_buf, length);
> if (rc) {
> fprintf(stderr, "vscsi_send_iu: DMA write failure !\n");
> }
> @@ -603,7 +603,7 @@ static const VMStateDescription vmstate_spapr_vscsi_req =
> {
> .minimum_version_id = 1,
> .fields = (VMStateField[]) {
> VMSTATE_BUFFER(crq.raw, vscsi_req),
> - VMSTATE_BUFFER(iu.srp.reserved, vscsi_req),
> + VMSTATE_BUFFER(viosrp_iu_buf, vscsi_req),
> VMSTATE_UINT32(qtag, vscsi_req),
> VMSTATE_BOOL(active, vscsi_req),
> VMSTATE_UINT32(data_len, vscsi_req),
> @@ -1104,7 +1104,7 @@ static void vscsi_got_payload(VSCSIState *s, vscsi_crq
> *crq)
> }
>
> /* XXX Handle failure differently ? */
> - if (spapr_vio_dma_read(&s->vdev, crq->s.IU_data_ptr, &req->iu,
> + if (spapr_vio_dma_read(&s->vdev, crq->s.IU_data_ptr, &req->viosrp_iu_buf,
> crq->s.IU_length)) {
> fprintf(stderr, "vscsi_got_payload: DMA read failure !\n");
> vscsi_put_req(req);
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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