From: Thomas Huth <thuth@redhat.com>
Date: Mon, 4 Jul 2022 11:19:01 +0000 (+0200)
Subject: pc-bios/s390-ccw/virtio-blkdev: Request the right feature bits
X-Git-Tag: qemu-xen-4.18.0-rc5~628^2~7
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=9125a314cca4a1838b09305a87d8efb98f80ab67;p=qemu-xen.git

pc-bios/s390-ccw/virtio-blkdev: Request the right feature bits

The virtio-blk code uses the block size and geometry fields in the
config area. According to the virtio-spec, these have to be negotiated
with the right feature bits during initialization, otherwise they
might not be available. QEMU is so far very forgiving and always
provides them, but we should not rely on this behavior, so let's
better request them properly via the VIRTIO_BLK_F_GEOMETRY and
VIRTIO_BLK_F_BLK_SIZE feature bits.

Message-Id: <20220704111903.62400-11-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
---

diff --git a/pc-bios/s390-ccw/virtio-blkdev.c b/pc-bios/s390-ccw/virtio-blkdev.c
index c175b66a47..8271c47296 100644
--- a/pc-bios/s390-ccw/virtio-blkdev.c
+++ b/pc-bios/s390-ccw/virtio-blkdev.c
@@ -13,6 +13,9 @@
 #include "virtio.h"
 #include "virtio-scsi.h"
 
+#define VIRTIO_BLK_F_GEOMETRY   (1 << 4)
+#define VIRTIO_BLK_F_BLK_SIZE   (1 << 6)
+
 static int virtio_blk_read_many(VDev *vdev, ulong sector, void *load_addr,
                                 int sec_num)
 {
@@ -223,6 +226,7 @@ int virtio_blk_setup_device(SubChannelId schid)
 {
     VDev *vdev = virtio_get_device();
 
+    vdev->guest_features[0] = VIRTIO_BLK_F_GEOMETRY | VIRTIO_BLK_F_BLK_SIZE;
     vdev->schid = schid;
     virtio_setup_ccw(vdev);