From: Jared Rossi <jrossi@linux.ibm.com>

Store the device type (e.g. block) directly and an attribute of the VDev rather
than assume all devices can be identified by accessing CCW specific sense data.

Signed-off-by: Jared Rossi <jrossi@linux.ibm.com>
---
 pc-bios/s390-ccw/main.c          |  2 +-
 pc-bios/s390-ccw/virtio-blkdev.c | 39 +++++++++++++++++++-------------
 pc-bios/s390-ccw/virtio.c        | 11 ++++++---
 pc-bios/s390-ccw/virtio.h        |  1 +
 4 files changed, 33 insertions(+), 20 deletions(-)

diff --git a/pc-bios/s390-ccw/main.c b/pc-bios/s390-ccw/main.c
index 0446d5de67..e7c3d9b2d6 100644
--- a/pc-bios/s390-ccw/main.c
+++ b/pc-bios/s390-ccw/main.c
@@ -250,7 +250,7 @@ static int virtio_setup(void)
     vdev->is_cdrom = false;
     int ret;
 
-    switch (vdev->senseid.cu_model) {
+    switch (vdev->dev_type) {
     case VIRTIO_ID_NET:
         puts("Network boot device detected");
         return 0;
diff --git a/pc-bios/s390-ccw/virtio-blkdev.c b/pc-bios/s390-ccw/virtio-blkdev.c
index 019c2718b1..9cc40e9108 100644
--- a/pc-bios/s390-ccw/virtio-blkdev.c
+++ b/pc-bios/s390-ccw/virtio-blkdev.c
@@ -53,14 +53,14 @@ int virtio_read_many(unsigned long sector, void *load_addr, int sec_num)
 {
     VDev *vdev = virtio_get_device();
 
-    switch (vdev->senseid.cu_model) {
+    switch (vdev->dev_type) {
     case VIRTIO_ID_BLOCK:
         return virtio_blk_read_many(vdev, sector, load_addr, sec_num);
     case VIRTIO_ID_SCSI:
         return virtio_scsi_read_many(vdev, sector, load_addr, sec_num);
+    default:
+        return -1;
     }
-
-    return -1;
 }
 
 unsigned long virtio_load_direct(unsigned long rec_list1, unsigned long rec_list2,
@@ -119,7 +119,7 @@ void virtio_assume_iso9660(void)
 {
     VDev *vdev = virtio_get_device();
 
-    switch (vdev->senseid.cu_model) {
+    switch (vdev->dev_type) {
     case VIRTIO_ID_BLOCK:
         vdev->guessed_disk_nature = VIRTIO_GDN_SCSI;
         vdev->config.blk.blk_size = VIRTIO_ISO_BLOCK_SIZE;
@@ -129,6 +129,8 @@ void virtio_assume_iso9660(void)
     case VIRTIO_ID_SCSI:
         vdev->scsi_block_size = VIRTIO_ISO_BLOCK_SIZE;
         break;
+    default:
+        return;
     }
 }
 
@@ -139,13 +141,15 @@ void virtio_assume_eckd(void)
     vdev->guessed_disk_nature = VIRTIO_GDN_DASD;
     vdev->blk_factor = 1;
     vdev->config.blk.physical_block_exp = 0;
-    switch (vdev->senseid.cu_model) {
+    switch (vdev->dev_type) {
     case VIRTIO_ID_BLOCK:
         vdev->config.blk.blk_size = VIRTIO_DASD_DEFAULT_BLOCK_SIZE;
         break;
     case VIRTIO_ID_SCSI:
         vdev->config.blk.blk_size = vdev->scsi_block_size;
         break;
+    default:
+        break;
     }
     vdev->config.blk.geometry.heads = 15;
     vdev->config.blk.geometry.sectors =
@@ -162,50 +166,52 @@ bool virtio_ipl_disk_is_valid(void)
         return true;
     }
 
-    return (vdev->senseid.cu_model == VIRTIO_ID_BLOCK ||
-            vdev->senseid.cu_model == VIRTIO_ID_SCSI) &&
-           blksize >= 512 && blksize <= 4096;
+    return (vdev->dev_type == VIRTIO_ID_BLOCK || vdev->dev_type == VIRTIO_ID_SCSI)
+            && blksize >= 512 && blksize <= 4096;
 }
 
 int virtio_get_block_size(void)
 {
     VDev *vdev = virtio_get_device();
 
-    switch (vdev->senseid.cu_model) {
+    switch (vdev->dev_type) {
     case VIRTIO_ID_BLOCK:
         return vdev->config.blk.blk_size;
     case VIRTIO_ID_SCSI:
         return vdev->scsi_block_size;
+    default:
+        return 0;
     }
-    return 0;
 }
 
 uint8_t virtio_get_heads(void)
 {
     VDev *vdev = virtio_get_device();
 
-    switch (vdev->senseid.cu_model) {
+    switch (vdev->dev_type) {
     case VIRTIO_ID_BLOCK:
         return vdev->config.blk.geometry.heads;
     case VIRTIO_ID_SCSI:
         return vdev->guessed_disk_nature == VIRTIO_GDN_DASD
                ? vdev->config.blk.geometry.heads : 255;
+    default:
+        return 0;
     }
-    return 0;
 }
 
 uint8_t virtio_get_sectors(void)
 {
     VDev *vdev = virtio_get_device();
 
-    switch (vdev->senseid.cu_model) {
+    switch (vdev->dev_type) {
     case VIRTIO_ID_BLOCK:
         return vdev->config.blk.geometry.sectors;
     case VIRTIO_ID_SCSI:
         return vdev->guessed_disk_nature == VIRTIO_GDN_DASD
                ? vdev->config.blk.geometry.sectors : 63;
+    default:
+        return 0;
     }
-    return 0;
 }
 
 uint64_t virtio_get_blocks(void)
@@ -213,13 +219,14 @@ uint64_t virtio_get_blocks(void)
     VDev *vdev = virtio_get_device();
     const uint64_t factor = virtio_get_block_size() / VIRTIO_SECTOR_SIZE;
 
-    switch (vdev->senseid.cu_model) {
+    switch (vdev->dev_type) {
     case VIRTIO_ID_BLOCK:
         return vdev->config.blk.capacity / factor;
     case VIRTIO_ID_SCSI:
         return vdev->scsi_last_block / factor;
+    default:
+        return 0;
     }
-    return 0;
 }
 
 int virtio_blk_setup_device(SubChannelId schid)
diff --git a/pc-bios/s390-ccw/virtio.c b/pc-bios/s390-ccw/virtio.c
index f384a990dc..5dd407d5c9 100644
--- a/pc-bios/s390-ccw/virtio.c
+++ b/pc-bios/s390-ccw/virtio.c
@@ -41,7 +41,7 @@ VDev *virtio_get_device(void)
 
 VirtioDevType virtio_get_device_type(void)
 {
-    return vdev.senseid.cu_model;
+    return vdev.dev_type;
 }
 
 /* virtio spec v1.0 para 4.3.3.2 */
@@ -248,7 +248,7 @@ int virtio_setup_ccw(VDev *vdev)
         return -EIO;
     }
 
-    switch (vdev->senseid.cu_model) {
+    switch (vdev->dev_type) {
     case VIRTIO_ID_NET:
         vdev->nr_vqs = 2;
         vdev->cmd_vr_idx = 0;
@@ -346,12 +346,17 @@ bool virtio_is_supported(SubChannelId schid)
                 true)) {
         return false;
     }
+
+    vdev.dev_type = vdev.senseid.cu_model;
+
     if (vdev.senseid.cu_type == 0x3832) {
-        switch (vdev.senseid.cu_model) {
+        switch (vdev.dev_type) {
         case VIRTIO_ID_BLOCK:
         case VIRTIO_ID_SCSI:
         case VIRTIO_ID_NET:
             return true;
+        default:
+            return false;
         }
     }
     return false;
diff --git a/pc-bios/s390-ccw/virtio.h b/pc-bios/s390-ccw/virtio.h
index 391d6ff2f7..39b507b221 100644
--- a/pc-bios/s390-ccw/virtio.h
+++ b/pc-bios/s390-ccw/virtio.h
@@ -239,6 +239,7 @@ struct VDev {
     SubChannelId schid;
     SenseId senseid;
     S390IplType ipl_type;
+    VirtioDevType dev_type;
     union {
         VirtioBlkConfig blk;
         VirtioScsiConfig scsi;
-- 
2.52.0

On 1/27/2026 8:15 AM, jrossi@linux.ibm.com wrote:
> From: Jared Rossi<jrossi@linux.ibm.com>
>
> Store the device type (e.g. block) directly and an attribute of the VDev rather
> than assume all devices can be identified by accessing CCW specific sense data.

I think it should be "as an attribute"?


> Signed-off-by: Jared Rossi<jrossi@linux.ibm.com>
> ---
>   pc-bios/s390-ccw/main.c          |  2 +-
>   pc-bios/s390-ccw/virtio-blkdev.c | 39 +++++++++++++++++++-------------
>   pc-bios/s390-ccw/virtio.c        | 11 ++++++---
>   pc-bios/s390-ccw/virtio.h        |  1 +
>   4 files changed, 33 insertions(+), 20 deletions(-)

The patch looks good to me

Reviewed-by: Farhan Ali<alifm@linux.ibm.com>

On 27/01/2026 17.15, jrossi@linux.ibm.com wrote:
> From: Jared Rossi <jrossi@linux.ibm.com>
> 
> Store the device type (e.g. block) directly and an attribute of the VDev rather
> than assume all devices can be identified by accessing CCW specific sense data.
> 
> Signed-off-by: Jared Rossi <jrossi@linux.ibm.com>
> ---
...
> @@ -346,12 +346,17 @@ bool virtio_is_supported(SubChannelId schid)
>                   true)) {
>           return false;
>       }
> +
> +    vdev.dev_type = vdev.senseid.cu_model;
> +
>       if (vdev.senseid.cu_type == 0x3832) {
> -        switch (vdev.senseid.cu_model) {
> +        switch (vdev.dev_type) {
>           case VIRTIO_ID_BLOCK:
>           case VIRTIO_ID_SCSI:
>           case VIRTIO_ID_NET:
>               return true;
> +        default:
> +            return false;
>           }
>       }
>       return false;
It feels a bit weird to set up vdev.dev_type in a function called 
"virtio_is_supported" (I'd rather expect a function with that name to check 
only stuff, not to set values) ... but we're doing the same with  vdev.schid 
there, too, so I guess it's ok for now. In the long run, we should maybe 
split up virtio_is_supported in two pieces, one function that does early 
setup, and one that is checking whether it's a supported virtio device.

Anyway, for now:
Reviewed-by: Thomas Huth <thuth@redhat.com>