ahci-test: test atapi read_cd with bcl, nb_sectors = 0

Commit 9ef2e93f introduced the concept of tagging ATAPI commands as
NONDATA, but this introduced a regression for certain commands better
described as CONDDATA. read_cd is such a command that both requires
a non-zero BCL if a transfer size is set, but is perfectly content to
accept a zero BCL if the transfer size is 0.

This test adds a regression test for the case where BCL and nb_sectors
are both 0.

Flesh out the CDROM tests by:

(1) Allowing the test to specify a BCL
(2) Allowing the buffer comparison test to compare a 0-size buffer
(3) Fix the BCL specification in libqos (It is LE, not BE)
(4) Add a nice human-readable message for future SCSI command additions

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1477970211-25754-4-git-send-email-jsnow@redhat.com
[Line length edit --js]
Signed-off-by: John Snow <jsnow@redhat.com>

tests/ahci-test.c

@@ -1473,8 +1473,13 @@ static int ahci_cb_cmp_buff(AHCIQState *ahci, AHCICommand *cmd,
                             const AHCIOpts *opts)
 {
     unsigned char *tx = opts->opaque;
-    unsigned char *rx = g_malloc0(opts->size);
+    unsigned char *rx;
 
+    if (!opts->size) {
+        return 0;
+    }
+
+    rx = g_malloc0(opts->size);
     bufread(opts->buffer, rx, opts->size);
     g_assert_cmphex(memcmp(tx, rx, opts->size), ==, 0);
     g_free(rx);
@@ -1482,7 +1487,8 @@ static int ahci_cb_cmp_buff(AHCIQState *ahci, AHCICommand *cmd,
     return 0;
 }
 
-static void ahci_test_cdrom(int nsectors, bool dma)
+static void ahci_test_cdrom(int nsectors, bool dma, uint8_t cmd,
+                            bool override_bcl, uint16_t bcl)
 {
     AHCIQState *ahci;
     unsigned char *tx;
@@ -1493,6 +1499,8 @@ static void ahci_test_cdrom(int nsectors, bool dma)
         .atapi = true,
         .atapi_dma = dma,
         .post_cb = ahci_cb_cmp_buff,
+        .set_bcl = override_bcl,
+        .bcl = bcl,
     };
     uint64_t iso_size = ATAPI_SECTOR_SIZE * (nsectors + 1);
 
@@ -1506,7 +1514,7 @@ static void ahci_test_cdrom(int nsectors, bool dma)
                                 "-device ide-cd,drive=drive0 ", iso);
 
     /* Build & Send AHCI command */
-    ahci_exec(ahci, ahci_port_select(ahci), CMD_ATAPI_READ_10, &opts);
+    ahci_exec(ahci, ahci_port_select(ahci), cmd, &opts);
 
     /* Cleanup */
     g_free(tx);
@@ -1514,24 +1522,36 @@ static void ahci_test_cdrom(int nsectors, bool dma)
     remove_iso(fd, iso);
 }
 
+static void ahci_test_cdrom_read10(int nsectors, bool dma)
+{
+    ahci_test_cdrom(nsectors, dma, CMD_ATAPI_READ_10, false, 0);
+}
+
 static void test_cdrom_dma(void)
 {
-    ahci_test_cdrom(1, true);
+    ahci_test_cdrom_read10(1, true);
 }
 
 static void test_cdrom_dma_multi(void)
 {
-    ahci_test_cdrom(3, true);
+    ahci_test_cdrom_read10(3, true);
 }
 
 static void test_cdrom_pio(void)
 {
-    ahci_test_cdrom(1, false);
+    ahci_test_cdrom_read10(1, false);
 }
 
 static void test_cdrom_pio_multi(void)
 {
-    ahci_test_cdrom(3, false);
+    ahci_test_cdrom_read10(3, false);
+}
+
+/* Regression test: Test that a READ_CD command with a BCL of 0 but a size of 0
+ * completes as a NOP instead of erroring out. */
+static void test_atapi_bcl(void)
+{
+    ahci_test_cdrom(0, false, CMD_ATAPI_READ_CD, true, 0);
 }
 
 /******************************************************************************/
@@ -1823,6 +1843,8 @@ int main(int argc, char **argv)
     qtest_add_func("/ahci/cdrom/pio/single", test_cdrom_pio);
     qtest_add_func("/ahci/cdrom/pio/multi", test_cdrom_pio_multi);
 
+    qtest_add_func("/ahci/cdrom/pio/bcl", test_atapi_bcl);
+
     ret = g_test_run();
 
     /* Cleanup */

tests/libqos/ahci.c

@@ -633,7 +633,8 @@ void ahci_exec(AHCIQState *ahci, uint8_t port,
 
     /* Command creation */
     if (opts->atapi) {
-        cmd = ahci_atapi_command_create(op);
+        uint16_t bcl = opts->set_bcl ? opts->bcl : ATAPI_SECTOR_SIZE;
+        cmd = ahci_atapi_command_create(op, bcl);
         if (opts->atapi_dma) {
             ahci_command_enable_atapi_dma(cmd);
         }
@@ -864,16 +865,12 @@ AHCICommand *ahci_command_create(uint8_t command_name)
     return cmd;
 }
 
-AHCICommand *ahci_atapi_command_create(uint8_t scsi_cmd)
+AHCICommand *ahci_atapi_command_create(uint8_t scsi_cmd, uint16_t bcl)
 {
     AHCICommand *cmd = ahci_command_create(CMD_PACKET);
     cmd->atapi_cmd = g_malloc0(16);
     cmd->atapi_cmd[0] = scsi_cmd;
-    /* ATAPI needs a PIO transfer chunk size set inside of the LBA registers.
+    stw_le_p(&cmd->fis.lba_lo[1], bcl);
-     * The block/sector size is a natural default. */
-    cmd->fis.lba_lo[1] = ATAPI_SECTOR_SIZE >> 8 & 0xFF;
-    cmd->fis.lba_lo[2] = ATAPI_SECTOR_SIZE & 0xFF;
-
     return cmd;
 }
 
@@ -901,12 +898,17 @@ static void ahci_atapi_command_set_offset(AHCICommand *cmd, uint64_t lba)
 
     switch (cbd[0]) {
     case CMD_ATAPI_READ_10:
+    case CMD_ATAPI_READ_CD:
         g_assert_cmpuint(lba, <=, UINT32_MAX);
         stl_be_p(&cbd[2], lba);
         break;
     default:
         /* SCSI doesn't have uniform packet formats,
          * so you have to add support for it manually. Sorry! */
+        fprintf(stderr, "The Libqos AHCI driver does not support the "
+                "set_offset operation for ATAPI command 0x%02x, "
+                "please add support.\n",
+                cbd[0]);
         g_assert_not_reached();
     }
 }
@@ -951,6 +953,7 @@ static void ahci_atapi_set_size(AHCICommand *cmd, uint64_t xbytes)
 {
     unsigned char *cbd = cmd->atapi_cmd;
     uint64_t nsectors = xbytes / 2048;
+    uint32_t tmp;
     g_assert(cbd);
 
     switch (cbd[0]) {
@@ -958,9 +961,20 @@ static void ahci_atapi_set_size(AHCICommand *cmd, uint64_t xbytes)
         g_assert_cmpuint(nsectors, <=, UINT16_MAX);
         stw_be_p(&cbd[7], nsectors);
         break;
+    case CMD_ATAPI_READ_CD:
+        /* 24bit BE store */
+        g_assert_cmpuint(nsectors, <, 1ULL << 24);
+        tmp = nsectors;
+        cbd[6] = (tmp & 0xFF0000) >> 16;
+        cbd[7] = (tmp & 0xFF00) >> 8;
+        cbd[8] = (tmp & 0xFF);
+        break;
     default:
         /* SCSI doesn't have uniform packet formats,
          * so you have to add support for it manually. Sorry! */
+        fprintf(stderr, "The Libqos AHCI driver does not support the set_size "
+                "operation for ATAPI command 0x%02x, please add support.\n",
+                cbd[0]);
         g_assert_not_reached();
     }
 }

tests/libqos/ahci.h

@@ -288,6 +288,7 @@ enum {
 /* ATAPI Commands */
 enum {
     CMD_ATAPI_READ_10 = 0x28,
+    CMD_ATAPI_READ_CD = 0xbe,
 };
 
 /* AHCI Command Header Flags & Masks*/
@@ -462,12 +463,14 @@ typedef struct AHCICommand AHCICommand;
 
 /* Options to ahci_exec */
 typedef struct AHCIOpts {
-    size_t size;
+    size_t size;        /* Size of transfer */
-    unsigned prd_size;
+    unsigned prd_size;  /* Size per-each PRD */
-    uint64_t lba;
+    bool set_bcl;       /* Override the default BCL of ATAPI_SECTOR_SIZE */
-    uint64_t buffer;
+    unsigned bcl;       /* Byte Count Limit, for ATAPI PIO */
-    bool atapi;
+    uint64_t lba;       /* Starting LBA offset */
-    bool atapi_dma;
+    uint64_t buffer;    /* Pointer to source or destination guest buffer */
+    bool atapi;         /* ATAPI command? */
+    bool atapi_dma;     /* Use DMA for ATAPI? */
     bool error;
     int (*pre_cb)(AHCIQState*, AHCICommand*, const struct AHCIOpts *);
     int (*mid_cb)(AHCIQState*, AHCICommand*, const struct AHCIOpts *);
@@ -599,7 +602,7 @@ void ahci_exec(AHCIQState *ahci, uint8_t port,
 
 /* Command: Fine-grained lifecycle */
 AHCICommand *ahci_command_create(uint8_t command_name);
-AHCICommand *ahci_atapi_command_create(uint8_t scsi_cmd);
+AHCICommand *ahci_atapi_command_create(uint8_t scsi_cmd, uint16_t bcl);
 void ahci_command_commit(AHCIQState *ahci, AHCICommand *cmd, uint8_t port);
 void ahci_command_issue(AHCIQState *ahci, AHCICommand *cmd);
 void ahci_command_issue_async(AHCIQState *ahci, AHCICommand *cmd);