[PULL 03/15] pc-bios/s390-ccw: Add per-queue notification offset for multi-queue virtio configurations

[Cornelia Huck <cohuck@redhat.com>]

From: Zhuoying Cai <zycai@linux.ibm.com>

The initial support for virtio-blk-pci IPL devices used a single virt-queue, but
other device types require multiple queues, and for PCI device types this also
requires a per-queue notification offset.

Add a PCI notify field to the VRing struct so that each queue has a unique
notify offset as defined in the virtio spec.

Signed-off-by: Zhuoying Cai <zycai@linux.ibm.com>
Signed-off-by: Jared Rossi <jrossi@linux.ibm.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
Message-ID: <20260630141917.673995-4-jrossi@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
---
 pc-bios/s390-ccw/virtio-pci.c | 38 +++++++++++++++++++++--------------
 pc-bios/s390-ccw/virtio-pci.h |  2 +-
 pc-bios/s390-ccw/virtio.c     |  2 +-
 pc-bios/s390-ccw/virtio.h     |  1 +
 4 files changed, 26 insertions(+), 17 deletions(-)

diff --git a/pc-bios/s390-ccw/virtio-pci.c b/pc-bios/s390-ccw/virtio-pci.c
index 53bdb52e76ab..2c83ec4f1316 100644
--- a/pc-bios/s390-ccw/virtio-pci.c
+++ b/pc-bios/s390-ccw/virtio-pci.c
@@ -21,7 +21,6 @@ VirtioPciCap c_cap; /* Common capabilities  */
 VirtioPciCap d_cap; /* Device capabilities  */
 VirtioPciCap n_cap; /* Notify capabilities  */
 uint32_t notify_mult;
-uint16_t q_notify_offset;
 
 static int virtio_pci_set_status(uint8_t status)
 {
@@ -74,10 +73,10 @@ int virtio_pci_reset(VDev *vdev)
     return 0;
 }
 
-long virtio_pci_notify(int vq_id)
+long virtio_pci_notify(VRing *vr)
 {
-    uint32_t offset = n_cap.off + notify_mult * q_notify_offset;
-    return vpci_bswap16_write(offset, n_cap.bar, (uint16_t) vq_id);
+    uint32_t offset = n_cap.off + notify_mult * vr->pci_notify;
+    return vpci_bswap16_write(offset, n_cap.bar, (uint16_t) vr->id);
 }
 
 /*
@@ -301,8 +300,7 @@ static int virtio_pci_read_pci_cap_config(void)
     }
 
     rc = vpci_read_bswap32(pos + VPCI_N_CAP_MULT, PCI_CFGBAR, &notify_mult);
-    if (rc || vpci_read_bswap16(c_cap.off + VPCI_C_OFFSET_Q_NOFF, c_cap.bar,
-                                &q_notify_offset)) {
+    if (rc) {
         puts("Failed to read notification queue configuration");
         return -EIO;
     }
@@ -332,7 +330,6 @@ int virtio_pci_setup(VDev *vdev)
     VRing *vr;
     int rc;
     uint8_t status;
-    uint16_t vq_size;
     int i = 0;
 
     vdev->guessed_disk_nature = VIRTIO_GDN_NONE;
@@ -380,28 +377,39 @@ int virtio_pci_setup(VDev *vdev)
         return -EIO;
     }
 
-    if (vpci_read_bswap16(VPCI_C_OFFSET_Q_SIZE, c_cap.bar, &vq_size)) {
-        puts("Failed to read virt-queue configuration");
-        return -EIO;
-    }
-
     /* Configure virt-queues for pci */
     for (i = 0; i < vdev->nr_vqs; i++) {
+        uint16_t vq_size;
+        uint16_t vq_notify;
         VqInfo info = {
             .queue = (unsigned long long) virtio_get_ring_area(i),
             .align = KVM_S390_VIRTIO_RING_ALIGN,
             .index = i,
-            .num = vq_size,
+            .num = 0,
         };
 
         vr = &vdev->vrings[i];
-        vring_init(vr, &info);
 
-        if (vpci_set_selected_vq(vr->id)) {
+        if (vpci_set_selected_vq(i)) {
             puts("Failed to set selected virt-queue");
             return -EIO;
         }
 
+        if (vpci_read_bswap16(c_cap.off + VPCI_C_OFFSET_Q_SIZE, c_cap.bar, &vq_size)) {
+            printf("Failed to read virt-queue %d size\n", i);
+            return -EIO;
+        }
+
+        info.num = vq_size;
+
+        if (vpci_read_bswap16(c_cap.off + VPCI_C_OFFSET_Q_NOFF, c_cap.bar, &vq_notify)) {
+            printf("Failed to read virt-queue %d notify offset\n", i);
+            return -EIO;
+        }
+
+        vr->pci_notify = vq_notify;
+        vring_init(vr, &info);
+
         rc = set_pci_vq_addr(VPCI_C_OFFSET_Q_DESCLO, vr->desc);
         rc |= set_pci_vq_addr(VPCI_C_OFFSET_Q_AVAILLO, vr->avail);
         rc |= set_pci_vq_addr(VPCI_C_OFFSET_Q_USEDLO, vr->used);
diff --git a/pc-bios/s390-ccw/virtio-pci.h b/pc-bios/s390-ccw/virtio-pci.h
index 90d07cb9a76a..2494df161988 100644
--- a/pc-bios/s390-ccw/virtio-pci.h
+++ b/pc-bios/s390-ccw/virtio-pci.h
@@ -64,7 +64,7 @@ typedef struct VirtioPciCap  VirtioPciCap;
 
 void virtio_pci_id2type(VDev *vdev, uint16_t device_id);
 int virtio_pci_reset(VDev *vdev);
-long virtio_pci_notify(int vq_id);
+long virtio_pci_notify(VRing *vr);
 int virtio_pci_setup(VDev *vdev);
 int virtio_pci_setup_device(void);
 
diff --git a/pc-bios/s390-ccw/virtio.c b/pc-bios/s390-ccw/virtio.c
index 7883871033c4..df04479aa69c 100644
--- a/pc-bios/s390-ccw/virtio.c
+++ b/pc-bios/s390-ccw/virtio.c
@@ -114,7 +114,7 @@ bool vring_notify(VRing *vr)
         vr->cookie = virtio_ccw_notify(vdev.schid, vr->id, vr->cookie);
         break;
     case S390_IPL_TYPE_PCI:
-        vr->cookie = virtio_pci_notify(vr->id);
+        vr->cookie = virtio_pci_notify(vr);
         break;
     default:
         return 1;
diff --git a/pc-bios/s390-ccw/virtio.h b/pc-bios/s390-ccw/virtio.h
index d32a4830cad1..75ae5bdbc229 100644
--- a/pc-bios/s390-ccw/virtio.h
+++ b/pc-bios/s390-ccw/virtio.h
@@ -107,6 +107,7 @@ struct VRing {
     VRingUsed *used;
     long cookie;
     int id;
+    uint16_t pci_notify;
 };
 typedef struct VRing VRing;
 
-- 
2.54.0