scsi-disk: parse MODE SELECT commands and parameters
This adds the bulk of the parsing code for MODE SELECT, including
breaking out changes to different mode pages, and checking that only
changeable values are modified.
In order to report errors correctly two passes are made through the
parameters; the first only looks for errors, the second actually
applies the changes to the mode page.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index 7015420..ad6c00d 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -43,6 +43,7 @@
#define SCSI_DMA_BUF_SIZE 131072
#define SCSI_MAX_INQUIRY_LEN 256
+#define SCSI_MAX_MODE_LEN 256
typedef struct SCSIDiskState SCSIDiskState;
@@ -1283,6 +1284,159 @@
scsi_req_complete(&r->req, GOOD);
}
+static int scsi_disk_check_mode_select(SCSIDiskState *s, int page,
+ uint8_t *inbuf, int inlen)
+{
+ uint8_t mode_current[SCSI_MAX_MODE_LEN];
+ uint8_t mode_changeable[SCSI_MAX_MODE_LEN];
+ uint8_t *p;
+ int len, expected_len, changeable_len, i;
+
+ /* The input buffer does not include the page header, so it is
+ * off by 2 bytes.
+ */
+ expected_len = inlen + 2;
+ if (expected_len > SCSI_MAX_MODE_LEN) {
+ return -1;
+ }
+
+ p = mode_current;
+ memset(mode_current, 0, inlen + 2);
+ len = mode_sense_page(s, page, &p, 0);
+ if (len < 0 || len != expected_len) {
+ return -1;
+ }
+
+ p = mode_changeable;
+ memset(mode_changeable, 0, inlen + 2);
+ changeable_len = mode_sense_page(s, page, &p, 1);
+ assert(changeable_len == len);
+
+ /* Check that unchangeable bits are the same as what MODE SENSE
+ * would return.
+ */
+ for (i = 2; i < len; i++) {
+ if (((mode_current[i] ^ inbuf[i - 2]) & ~mode_changeable[i]) != 0) {
+ return -1;
+ }
+ }
+ return 0;
+}
+
+static void scsi_disk_apply_mode_select(SCSIDiskState *s, int page, uint8_t *p)
+{
+}
+
+static int mode_select_pages(SCSIDiskReq *r, uint8_t *p, int len, bool change)
+{
+ SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
+
+ while (len > 0) {
+ int page, subpage, page_len;
+
+ /* Parse both possible formats for the mode page headers. */
+ page = p[0] & 0x3f;
+ if (p[0] & 0x40) {
+ if (len < 4) {
+ goto invalid_param_len;
+ }
+ subpage = p[1];
+ page_len = lduw_be_p(&p[2]);
+ p += 4;
+ len -= 4;
+ } else {
+ if (len < 2) {
+ goto invalid_param_len;
+ }
+ subpage = 0;
+ page_len = p[1];
+ p += 2;
+ len -= 2;
+ }
+
+ if (subpage) {
+ goto invalid_param;
+ }
+ if (page_len > len) {
+ goto invalid_param_len;
+ }
+
+ if (!change) {
+ if (scsi_disk_check_mode_select(s, page, p, page_len) < 0) {
+ goto invalid_param;
+ }
+ } else {
+ scsi_disk_apply_mode_select(s, page, p);
+ }
+
+ p += page_len;
+ len -= page_len;
+ }
+ return 0;
+
+invalid_param:
+ scsi_check_condition(r, SENSE_CODE(INVALID_PARAM));
+ return -1;
+
+invalid_param_len:
+ scsi_check_condition(r, SENSE_CODE(INVALID_PARAM_LEN));
+ return -1;
+}
+
+static void scsi_disk_emulate_mode_select(SCSIDiskReq *r, uint8_t *inbuf)
+{
+ uint8_t *p = inbuf;
+ int cmd = r->req.cmd.buf[0];
+ int len = r->req.cmd.xfer;
+ int hdr_len = (cmd == MODE_SELECT ? 4 : 8);
+ int bd_len;
+ int pass;
+
+ /* We only support PF=1, SP=0. */
+ if ((r->req.cmd.buf[1] & 0x11) != 0x10) {
+ goto invalid_field;
+ }
+
+ if (len < hdr_len) {
+ goto invalid_param_len;
+ }
+
+ bd_len = (cmd == MODE_SELECT ? p[3] : lduw_be_p(&p[6]));
+ len -= hdr_len;
+ p += hdr_len;
+ if (len < bd_len) {
+ goto invalid_param_len;
+ }
+ if (bd_len != 0 && bd_len != 8) {
+ goto invalid_param;
+ }
+
+ len -= bd_len;
+ p += bd_len;
+
+ /* Ensure no change is made if there is an error! */
+ for (pass = 0; pass < 2; pass++) {
+ if (mode_select_pages(r, p, len, pass == 1) < 0) {
+ assert(pass == 0);
+ return;
+ }
+ }
+ scsi_req_complete(&r->req, GOOD);
+ return;
+
+invalid_param:
+ scsi_check_condition(r, SENSE_CODE(INVALID_PARAM));
+ return;
+
+invalid_param_len:
+ scsi_check_condition(r, SENSE_CODE(INVALID_PARAM_LEN));
+ return;
+
+invalid_field:
+ scsi_check_condition(r, SENSE_CODE(INVALID_FIELD));
+ return;
+}
+
static void scsi_disk_emulate_write_data(SCSIRequest *req)
{
SCSIDiskReq *r = DO_UPCAST(SCSIDiskReq, req, req);
@@ -1299,7 +1453,7 @@
case MODE_SELECT:
case MODE_SELECT_10:
/* This also clears the sense buffer for REQUEST SENSE. */
- scsi_req_complete(&r->req, GOOD);
+ scsi_disk_emulate_mode_select(r, r->iov.iov_base);
break;
default:
@@ -1532,19 +1686,9 @@
break;
case MODE_SELECT:
DPRINTF("Mode Select(6) (len %lu)\n", (long)r->req.cmd.xfer);
- /* We don't support mode parameter changes.
- Allow the mode parameter header + block descriptors only. */
- if (r->req.cmd.xfer > 12) {
- goto illegal_request;
- }
break;
case MODE_SELECT_10:
DPRINTF("Mode Select(10) (len %lu)\n", (long)r->req.cmd.xfer);
- /* We don't support mode parameter changes.
- Allow the mode parameter header + block descriptors only. */
- if (r->req.cmd.xfer > 16) {
- goto illegal_request;
- }
break;
case WRITE_SAME_10:
nb_sectors = lduw_be_p(&req->cmd.buf[7]);
