Re: [PATCH 1/2] scsi: Add buf_len parameter to scsi_req_new()

[Paolo Bonzini]

On 8/17/22 07:34, John Millikin wrote:
> The sigil SCSI_CMD_BUF_LEN_TODO() is used to indicate that the buffer
> length calculation is TODO it should be replaced by a better value,
> such as the length of a successful DMA read.

Let's just do it right:

diff --git a/hw/scsi/lsi53c895a.c b/hw/scsi/lsi53c895a.c
index e8a4a705e7..05a43ec807 100644
--- a/hw/scsi/lsi53c895a.c
+++ b/hw/scsi/lsi53c895a.c
@@ -864,7 +864,7 @@ static void lsi_do_command(LSIState *s)
     s->current = g_new0(lsi_request, 1);
     s->current->tag = s->select_tag;
     s->current->req = scsi_req_new(dev, s->current->tag, s->current_lun, buf,
-                                   SCSI_CMD_BUF_LEN_TODO(s->dbc), s->current);
+                                   s->dbc, s->current);
 
     n = scsi_req_enqueue(s->current->req);
     if (n) {
diff --git a/hw/scsi/megasas.c b/hw/scsi/megasas.c
index e887ae8adb..842edc3f9d 100644
--- a/hw/scsi/megasas.c
+++ b/hw/scsi/megasas.c
@@ -1053,7 +1053,6 @@ static int megasas_pd_get_info_submit(SCSIDevice *sdev, 
int lun,
     uint64_t pd_size;
     uint16_t pd_id = ((sdev->id & 0xFF) << 8) | (lun & 0xFF);
     uint8_t cmdbuf[6];
-    size_t cmdbuf_len = SCSI_CMD_BUF_LEN_TODO(sizeof(cmdbuf));
     size_t len;
     dma_addr_t residual;
 
@@ -1063,7 +1062,7 @@ static int megasas_pd_get_info_submit(SCSIDevice *sdev, int lun,
         info->inquiry_data[0] = 0x7f; /* Force PQual 0x3, PType 0x1f */
         info->vpd_page83[0] = 0x7f;
         megasas_setup_inquiry(cmdbuf, 0, sizeof(info->inquiry_data));
-        cmd->req = scsi_req_new(sdev, cmd->index, lun, cmdbuf, cmdbuf_len, 
cmd);
+        cmd->req = scsi_req_new(sdev, cmd->index, lun, cmdbuf, sizeof(cmdbuf), 
cmd);
         if (!cmd->req) {
             trace_megasas_dcmd_req_alloc_failed(cmd->index,
                                                 "PD get info std inquiry");
@@ -1081,7 +1080,7 @@ static int megasas_pd_get_info_submit(SCSIDevice *sdev, 
int lun,
         return MFI_STAT_INVALID_STATUS;
     } else if (info->inquiry_data[0] != 0x7f && info->vpd_page83[0] == 0x7f) {
         megasas_setup_inquiry(cmdbuf, 0x83, sizeof(info->vpd_page83));
-        cmd->req = scsi_req_new(sdev, cmd->index, lun, cmdbuf, cmdbuf_len, 
cmd);
+        cmd->req = scsi_req_new(sdev, cmd->index, lun, cmdbuf, sizeof(cmdbuf), 
cmd);
         if (!cmd->req) {
             trace_megasas_dcmd_req_alloc_failed(cmd->index,
                                                 "PD get info vpd inquiry");
diff --git a/hw/scsi/mptsas.c b/hw/scsi/mptsas.c
index 711613b5b1..a90c2546f1 100644
--- a/hw/scsi/mptsas.c
+++ b/hw/scsi/mptsas.c
@@ -324,8 +324,8 @@ static int mptsas_process_scsi_io_request(MPTSASState *s,
     }
 
     req->sreq = scsi_req_new(sdev, scsi_io->MsgContext,
-                            scsi_io->LUN[1], scsi_io->CDB,
-                            SCSI_CMD_BUF_LEN_TODO(SIZE_MAX), req);
+                             scsi_io->LUN[1], scsi_io->CDB,
+                             scsi_io->CDBLength, req);
 
     if (req->sreq->cmd.xfer > scsi_io->DataLength) {
         goto overrun;
diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
index 288ea12969..cc71524024 100644
--- a/hw/scsi/scsi-bus.c
+++ b/hw/scsi/scsi-bus.c
@@ -1707,7 +1707,6 @@ static int get_scsi_requests(QEMUFile *f, void *pv, 
size_t size,
 
     while ((sbyte = qemu_get_sbyte(f)) > 0) {
         uint8_t buf[SCSI_CMD_BUF_SIZE];
-        size_t buf_len;
         uint32_t tag;
         uint32_t lun;
         SCSIRequest *req;
@@ -1715,8 +1714,11 @@ static int get_scsi_requests(QEMUFile *f, void *pv, 
size_t size,
         qemu_get_buffer(f, buf, sizeof(buf));
         qemu_get_be32s(f, &tag);
         qemu_get_be32s(f, &lun);
-        buf_len = SCSI_CMD_BUF_LEN_TODO(sizeof(buf));
-        req = scsi_req_new(s, tag, lun, buf, buf_len, NULL);
+        /*
+         * A too-short CDB would have been rejected by scsi_req_new, so just 
use
+         * SCSI_CMD_BUF_SIZE as the CDB length.
+         */
+        req = scsi_req_new(s, tag, lun, buf, sizeof(buf), NULL);
         req->retry = (sbyte == 1);
         if (bus->info->load_request) {
             req->hba_private = bus->info->load_request(f, req);
diff --git a/hw/scsi/spapr_vscsi.c b/hw/scsi/spapr_vscsi.c
index c17bb47f7b..0a8cbf5a4b 100644
--- a/hw/scsi/spapr_vscsi.c
+++ b/hw/scsi/spapr_vscsi.c
@@ -783,7 +783,7 @@ static int vscsi_queue_cmd(VSCSIState *s, vscsi_req *req)
     union srp_iu *srp = &req_iu(req)->srp;
     SCSIDevice *sdev;
     int n, lun;
-    size_t cdb_len = SCSI_CMD_BUF_LEN_TODO(SIZE_MAX);
+    size_t cdb_len = sizeof (srp->cmd.cdb) + (srp->cmd.add_cdb_len & ~3);
 
     if ((srp->cmd.lun == 0 || be64_to_cpu(srp->cmd.lun) == SRP_REPORT_LUNS_WLUN)
       && srp->cmd.cdb[0] == REPORT_LUNS) {
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index 632e3aa58f..41f2a56301 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -673,7 +673,6 @@ static int virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI 
*s, VirtIOSCSIReq *req)
     VirtIOSCSICommon *vs = &s->parent_obj;
     SCSIDevice *d;
     int rc;
-    size_t cdb_len = SCSI_CMD_BUF_LEN_TODO(SIZE_MAX);
 
     rc = virtio_scsi_parse_req(req, sizeof(VirtIOSCSICmdReq) + vs->cdb_size,
                                sizeof(VirtIOSCSICmdResp) + vs->sense_size);
@@ -698,7 +697,7 @@ static int virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI 
*s, VirtIOSCSIReq *req)
     virtio_scsi_ctx_check(s, d);
     req->sreq = scsi_req_new(d, req->req.cmd.tag,
                              virtio_scsi_get_lun(req->req.cmd.lun),
-                             req->req.cmd.cdb, cdb_len, req);
+                             req->req.cmd.cdb, vs->cdb_size, req);
 
     if (req->sreq->cmd.mode != SCSI_XFER_NONE
         && (req->sreq->cmd.mode != req->mode ||
diff --git a/hw/scsi/vmw_pvscsi.c b/hw/scsi/vmw_pvscsi.c
index f845c88378..91e2f858ab 100644
--- a/hw/scsi/vmw_pvscsi.c
+++ b/hw/scsi/vmw_pvscsi.c
@@ -716,7 +716,6 @@ pvscsi_process_request_descriptor(PVSCSIState *s,
     SCSIDevice *d;
     PVSCSIRequest *r = pvscsi_queue_pending_descriptor(s, &d, descr);
     int64_t n;
-    size_t cdb_len = SCSI_CMD_BUF_LEN_TODO(SIZE_MAX);
 
     trace_pvscsi_process_req_descr(descr->cdb[0], descr->context);
 
@@ -731,7 +730,7 @@ pvscsi_process_request_descriptor(PVSCSIState *s,
         r->sg.elemAddr = descr->dataAddr;
     }
 
-    r->sreq = scsi_req_new(d, descr->context, r->lun, descr->cdb, cdb_len, r);
+    r->sreq = scsi_req_new(d, descr->context, r->lun, descr->cdb, 
descr->cdbLen, r);
     if (r->sreq->cmd.mode == SCSI_XFER_FROM_DEV &&
         (descr->flags & PVSCSI_FLAG_CMD_DIR_TODEVICE)) {
         r->cmp.hostStatus = BTSTAT_BADMSG;
diff --git a/hw/usb/dev-storage.c b/hw/usb/dev-storage.c
index 353e129fac..98639696e6 100644
--- a/hw/usb/dev-storage.c
+++ b/hw/usb/dev-storage.c
@@ -379,7 +379,6 @@ static void usb_msd_handle_data(USBDevice *dev, USBPacket 
*p)
     uint8_t devep = p->ep->nr;
     SCSIDevice *scsi_dev;
     uint32_t len;
-    size_t cdb_len = SCSI_CMD_BUF_LEN_TODO(SIZE_MAX);
 
     switch (p->pid) {
     case USB_TOKEN_OUT:
@@ -416,7 +415,7 @@ static void usb_msd_handle_data(USBDevice *dev, USBPacket 
*p)
                                      cbw.cmd_len, s->data_len);
             assert(le32_to_cpu(s->csw.residue) == 0);
             s->scsi_len = 0;
-            s->req = scsi_req_new(scsi_dev, tag, cbw.lun, cbw.cmd, cdb_len, 
NULL);
+            s->req = scsi_req_new(scsi_dev, tag, cbw.lun, cbw.cmd, 
cbw.cmd_len, NULL);
             if (s->commandlog) {
                 scsi_req_print(s->req);
             }
diff --git a/hw/usb/dev-uas.c b/hw/usb/dev-uas.c
index 768df8958c..5192b062d6 100644
--- a/hw/usb/dev-uas.c
+++ b/hw/usb/dev-uas.c
@@ -71,7 +71,7 @@ typedef struct {
     uint8_t    reserved_2;
     uint64_t   lun;
     uint8_t    cdb[16];
-    uint8_t    add_cdb[1];      /* not supported by QEMU */
+    uint8_t    add_cdb[1];
 } QEMU_PACKED  uas_iu_command;
 
 typedef struct {
@@ -699,7 +699,7 @@ static void usb_uas_command(UASDevice *uas, uas_iu *iu)
     UASRequest *req;
     uint32_t len;
     uint16_t tag = be16_to_cpu(iu->hdr.tag);
-    size_t cdb_len = SCSI_CMD_BUF_LEN_TODO(SIZE_MAX);
+    size_t cdb_len = sizeof(iu->command.cdb) + iu->command.add_cdb_length;
 
     if (iu->command.add_cdb_length > 0) {
         qemu_log_mask(LOG_UNIMP, "additional adb length not yet supported\n");
diff --git a/include/scsi/utils.h b/include/scsi/utils.h
index 1a36d25ee4..d5c8efa16e 100644
--- a/include/scsi/utils.h
+++ b/include/scsi/utils.h
@@ -144,10 +144,4 @@ int scsi_cdb_length(uint8_t *buf);
 int scsi_sense_from_errno(int errno_value, SCSISense *sense);
 int scsi_sense_from_host_status(uint8_t host_status, SCSISense *sense);
 
-/**
- * Annotates places where a SCSI command buffer is passed to scsi_req_new()
- * but haven't yet been updated to pass the buffer's true (populated) length.
- */
-#define SCSI_CMD_BUF_LEN_TODO(guess) guess
-
 #endif

(or something like that).

paolo