vms-ddc: probe non-virtio (SCSI/NVMe) disks so SHOW DEVICE is faithful on bare metal

distro/kernel/ovmx-x86_64.config

@@ -31,6 +31,22 @@ CONFIG_VIRTIO_PCI=y
 CONFIG_VIRTIO_BLK=y
 CONFIG_VIRTIO_NET=y
 
+# --- virtio-scsi (non-virtio-blk disks: bare-metal SATA/SCSI, vms-ddc / --
+# vms-47d) -------------------------------------------------------------
+# OVMX targets bare metal, where the system disk is SATA/SCSI/NVMe, not
+# virtio-blk. A prior attempt (reverted) tried NVMe here, but this minimal
+# from-source config lacks the MSI-X plumbing NVMe needs to bring up
+# /dev/nvme0n1 in the guest. virtio-scsi instead reuses the already-enabled
+# virtio transport above and presents disks as /dev/sd*, exercising the
+# SAME non-virtio probe path (vms_devtab_probe_disks()'s SATA/SCSI loop)
+# reliably in a minimal kernel. Built-in (=y, never =m -- the initramfs
+# loads no modules). test_kmod_disk.c attaches one real virtio-scsi disk
+# and proves the executive enters SDA0: for it.
+CONFIG_SCSI=y
+CONFIG_BLK_DEV_SD=y
+CONFIG_SCSI_LOWLEVEL=y
+CONFIG_SCSI_VIRTIO=y
+
 # --- Block layer (the virtio-blk system disk) -----------------------------
 CONFIG_BLOCK=y
 

src/kernel-core/vms_devtab.c

@@ -343,6 +343,63 @@ static void vms_devtab_probe_disks(void)
         pr_info("vms: disk unit %s -> %s (%u:%u)\n",
                 devnam, backing, exec_blockdev_major(dev), exec_blockdev_minor(dev));
     }
+
+    /*
+     * Beyond virtio-blk: real and bare-metal boots (the operator's Rule-9
+     * target) rarely have /dev/vd* -- their system disk is SATA/SCSI (/dev/sd*)
+     * or NVMe (/dev/nvmeNn1). Probing ONLY virtio left the device table with no
+     * disk row on those substrates, so `SHOW DEVICE <disk>:` returned NOSUCHDEV
+     * and a bare `SHOW DEVICE` showed only the console -- the "hollow" surface a
+     * user hits on non-virtio hardware (vms-ddc / vms-47d). These two families
+     * complete the documented device-native naming scheme. INV-6 is preserved
+     * exactly as the virtio loop above: exec_blockdev_lookup() must actually
+     * resolve the node before a unit is entered -- never a speculative row.
+     */
+    for (i = 0; i < VMS_DISK_UNITS; i++) {
+        char path[16];
+        char devnam[VMS_DEVNAM_SIZE];
+        char backing[VMS_BACKING_SIZE];
+        exec_dev_t dev;
+        int n;
+
+        n = snprintf(path, sizeof(path), "/dev/sd%c", 'a' + i);
+        if (n < 0 || n >= (int)sizeof(path))
+            continue;
+        if (exec_blockdev_lookup(path, &dev) != 0)
+            continue;
+
+        snprintf(devnam,  sizeof(devnam),  "SDA%u:", (unsigned)i * 100u);
+        snprintf(backing, sizeof(backing), "sd%c", 'a' + i);
+        vms_devtab_add_disk(devnam, backing,
+                            exec_blockdev_major(dev), exec_blockdev_minor(dev));
+    }
+
+    /*
+     * NVMe names a block device <controller>n<namespace> (nvme0n1, nvme1n1...).
+     * We probe namespace 1 of each controller -- the boot/system-disk case that
+     * covers essentially every single-namespace machine. Additional namespaces
+     * (nvme0n2...) are a documented, deliberate not-yet: they are entered by
+     * whatever probe actually resolves them, never by a speculative branch here
+     * (same rule the SATA/SCSI comment above states).
+     */
+    for (i = 0; i < VMS_DISK_UNITS; i++) {
+        char path[16];
+        char devnam[VMS_DEVNAM_SIZE];
+        char backing[VMS_BACKING_SIZE];
+        exec_dev_t dev;
+        int n;
+
+        n = snprintf(path, sizeof(path), "/dev/nvme%dn1", i);
+        if (n < 0 || n >= (int)sizeof(path))
+            continue;
+        if (exec_blockdev_lookup(path, &dev) != 0)
+            continue;
+
+        snprintf(devnam,  sizeof(devnam),  "NVME%u:", (unsigned)i * 100u);
+        snprintf(backing, sizeof(backing), "nvme%dn1", i);
+        vms_devtab_add_disk(devnam, backing,
+                            exec_blockdev_major(dev), exec_blockdev_minor(dev));
+    }
 }
 
 /*

src/kernel/vms_internal.h

@@ -1526,9 +1526,11 @@ int vms_devtab_init(void);
 void vms_devtab_cleanup(void);
 /*
  * Enter ONE disk unit the SUBSTRATE enumerated, for a substrate whose disks the
- * shared /dev/vd* probe cannot name (rd vms-618 -- NetBSD/vax MSCP units). Not
- * called on Linux, where vms_devtab_probe_disks() does the enumeration; declared
- * here so the shared facility source keeps one prototype on every substrate.
+ * shared /dev/vd* probe cannot name (rd vms-618 -- NetBSD/vax MSCP units). On
+ * Linux, vms_devtab_probe_disks() calls this too for the non-virtio-blk
+ * families it enumerates itself (SATA/SCSI /dev/sd*, NVMe /dev/nvmeNn1 --
+ * vms-ddc / vms-47d, bare-metal device-native naming); declared here so the
+ * shared facility source keeps one prototype on every substrate.
  */
 int vms_devtab_add_disk(const char *devnam, const char *backing,
                         uint32_t backing_major, uint32_t backing_minor);

tests/qemu/run_tests.sh

@@ -191,7 +191,15 @@ else
     echo "                the IMGACT-over-ACP test (vms-3e8e) needs an ODS-2 image volume on VDA400: (vde)" >&2
     exit 2
 fi
-trap 'rm -f "$ASSERT_TRANSCRIPT" "$OVMX_DISK0" "$OVMX_DISK1" "$OVMX_DISK2" "$OVMX_DISK3" "$OVMX_DISK4"' EXIT
+# A scratch SCSI disk (blank), attached as a REAL virtio-scsi disk below. Its
+# only purpose is to prove the executive's non-virtio disk probe: with a real
+# /dev/sda present in the guest, vms_devtab_probe_disks() must enter SDA0:
+# resolving to that node's real major:minor (test_kmod_disk.c asserts it against
+# an independent stat()). Blank is fine -- the probe resolves the node, it does
+# not read the contents. vms-ddc / vms-47d (device-native naming beyond virtio).
+OVMX_SCSI0=$(mktemp) || { echo "run_tests.sh: mktemp failed" >&2; exit 2; }
+truncate -s 16M "$OVMX_SCSI0"
+trap 'rm -f "$ASSERT_TRANSCRIPT" "$OVMX_DISK0" "$OVMX_DISK1" "$OVMX_DISK2" "$OVMX_DISK3" "$OVMX_DISK4" "$OVMX_SCSI0"' EXIT
 
 # One virtio-net NIC (vms-9d2). Exactly as the two virtio disks above give the
 # executive real block devices to enumerate into DK units, this gives it a real
@@ -273,6 +281,9 @@ OUTPUT=$(timeout "$TIMEOUT" $QEMU \
     -device virtio-blk-pci,drive=ovmxdisk3 \
     -drive if=none,id=ovmxdisk4,file="$OVMX_DISK4",format=raw \
     -device virtio-blk-pci,drive=ovmxdisk4 \
+    -device virtio-scsi-pci,id=scsi0 \
+    -drive if=none,id=ovmxscsi0,file="$OVMX_SCSI0",format=raw \
+    -device scsi-hd,drive=ovmxscsi0,bus=scsi0.0 \
     2>&1) || QEMU_RC=$?
 
 # Splice the assertion transcript (ttyS1, if this arch has one) back into
@@ -316,7 +327,7 @@ OUTPUT_FILE=$(mktemp) || { echo "run_tests.sh: mktemp failed" >&2; exit 2; }
 # ONE trap, both temp files: a second `trap ... EXIT` REPLACES the first
 # rather than stacking with it, so registering ASSERT_TRANSCRIPT's cleanup
 # separately above would have silently dropped it the moment this line ran.
-trap 'rm -f "$OUTPUT_FILE" "$ASSERT_TRANSCRIPT" "$OVMX_DISK0" "$OVMX_DISK1" "$OVMX_DISK2" "$OVMX_DISK3" "$OVMX_DISK4"' EXIT
+trap 'rm -f "$OUTPUT_FILE" "$ASSERT_TRANSCRIPT" "$OVMX_DISK0" "$OVMX_DISK1" "$OVMX_DISK2" "$OVMX_DISK3" "$OVMX_DISK4" "$OVMX_SCSI0"' EXIT
 printf '%s\n' "$OUTPUT" > "$OUTPUT_FILE"
 
 if harness_verdict_zero_failures "$OUTPUT_FILE"; then

tests/qemu/test_kmod_disk.c

@@ -68,7 +68,8 @@ int main(void)
     uint32_t vda_maj = 0, vda_min = 0, vdb_maj = 0, vdb_min = 0;
     uint32_t vdc_maj = 0, vdc_min = 0, vdd_maj = 0, vdd_min = 0;
     uint32_t vde_maj = 0, vde_min = 0;
-    int have_vda, have_vdb, have_vdc, have_vdd, have_vde;
+    uint32_t sda_maj = 0, sda_min = 0;
+    int have_vda, have_vdb, have_vdc, have_vdd, have_vde, have_sda;
 
     printf("=== test_kmod_disk: the executive names the machine's disks ===\n");
 
@@ -97,6 +98,14 @@ int main(void)
     CHECK(have_vdc, "/dev/vdc is present (third virtio disk attached to the guest)");
     CHECK(have_vdd, "/dev/vdd is present (fourth virtio disk attached to the guest)");
     CHECK(have_vde, "/dev/vde is present (fifth virtio disk attached to the guest)");
+    /* run_tests.sh also attaches ONE real virtio-scsi disk (vms-ddc / vms-47d):
+     * this is the non-virtio-blk disk the executive's probe must ALSO enumerate,
+     * so that SHOW DEVICE is not hollow on bare-metal boots (where the system
+     * disk is SATA/SCSI/NVMe, not virtio-blk -- the operator's SHOW DEVICE
+     * NOSUCHDEV). virtio-scsi presents as /dev/sda -- a real, non-virtio-blk
+     * kernel node -- exercising the same SATA/SCSI probe path bare metal uses. */
+    have_sda = (stat_devt("/dev/sda", &sda_maj, &sda_min) == 0);
+    CHECK(have_sda, "/dev/sda is present (a real virtio-scsi disk attached to the guest)");
 
     /* --------------------------------------------------------------
      * 1. VDA0: exists in the executive's table -- nothing in this
@@ -170,14 +179,37 @@ int main(void)
           "VDA400: backing dev_t matches /dev/vde as userspace stat()s it");
 
     /* --------------------------------------------------------------
-     * 6. Negative controls -- a resolver that always succeeded would be
+     * 6. SDA0: is the non-virtio-blk disk -- the real proof that the probe
+     *    reaches beyond /dev/vd*. It must exist in the executive's table,
+     *    back onto /dev/sda, and resolve to the SAME major:minor userspace
+     *    stat()s for that node. A probe that only knew virtio-blk would
+     *    leave SDA0: absent (SS$_NOSUCHDEV) -- which is exactly the hollow
+     *    SHOW DEVICE the operator hit on non-virtio hardware.
+     * -------------------------------------------------------------- */
+    memset(backing, 0, sizeof(backing));
+    maj = min = 0;
+    status = vms_kif_disk_resolve("SDA0:", backing, sizeof(backing), &maj, &min);
+    CHECK(status == SS_NORMAL,
+          "SDA0: exists in the executive's table (a non-virtio-blk SCSI disk was enumerated)");
+    CHECK(strcmp(backing, "sda") == 0,
+          "SDA0: backing device is sda (the executive's enumeration)");
+    CHECK(have_sda && maj == sda_maj && min == sda_min,
+          "SDA0: backing dev_t matches /dev/sda as userspace stat()s it");
+
+    /* --------------------------------------------------------------
+     * 7. Negative controls -- a resolver that always succeeded would be
      *    indistinguishable from one that works.
      * -------------------------------------------------------------- */
-    /* Five disks are attached (vda..vde), so there is no sixth unit. */
+    /* Five virtio disks are attached (vda..vde), so there is no sixth unit. */
     memset(backing, 0, sizeof(backing));
     status = vms_kif_disk_resolve("VDA500:", backing, sizeof(backing), &maj, &min);
     CHECK(status == SS_NOSUCHDEV,
           "a disk unit that does not exist reports SS$_NOSUCHDEV (no sixth disk attached)");
+    /* Only ONE virtio-scsi disk is attached, so SDA100: (a second) must miss. */
+    memset(backing, 0, sizeof(backing));
+    status = vms_kif_disk_resolve("SDA100:", backing, sizeof(backing), &maj, &min);
+    CHECK(status == SS_NOSUCHDEV,
+          "a second SCSI unit that does not exist reports SS$_NOSUCHDEV (only one attached)");
 
     /* OPA0: exists, but it is a TERMINAL -- it has no backing block device. */
     memset(backing, 0, sizeof(backing));