On 04/03/2026 03.59, [email protected] wrote:
From: Jared Rossi <[email protected]>
Add little-endian virt-queue configuration and support for virtio-blk-pci IPL
devices.
Signed-off-by: Jared Rossi <[email protected]>
---
...
+static int virtio_pci_get_blk_config(void)
+{
+ VirtioBlkConfig *cfg = &virtio_get_device()->config.blk;
+ int rc = vpci_read_flex(d_cap.off, d_cap.bar, cfg,
sizeof(VirtioBlkConfig));
+
+ /* single byte fields are not touched */
+ cfg->capacity = bswap64(cfg->capacity);
+ cfg->size_max = bswap32(cfg->size_max);
+ cfg->seg_max = bswap32(cfg->seg_max);
+
+ cfg->geometry.cylinders = bswap16(cfg->geometry.cylinders);
+
+ cfg->blk_size = bswap32(cfg->blk_size);
+ cfg->min_io_size = bswap16(cfg->min_io_size);
+ cfg->opt_io_size = bswap32(cfg->opt_io_size);
So it looks like you read a bunch of optional config fields here ...
+ return rc;
+}
...
+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;
+ vdev->cmd_vr_idx = 0;
+
+ if (virtio_pci_read_pci_cap_config()) {
+ puts("Invalid virtio PCI capabilities");
+ return -EIO;
+ }
+
+ if (enable_pci_bus_master()) {
+ return -EIO;
+ }
+
+ if (virtio_reset(vdev)) {
+ return -EIO;
+ }
+
+ status = VIRTIO_CONFIG_S_ACKNOWLEDGE;
+ if (virtio_pci_set_status(status)) {
+ puts("Virtio-pci device Failed to ACKNOWLEDGE");
+ return -EIO;
+ }
... so I think you should enable the corresponding feature bits in
vdev->guest_features[0] here? QEMU might be very forgiving and provide you
with the fields anyway, but let's better play safe. Something like:
vdev->guest_features[0] = VIRTIO_BLK_F_SIZE_MAX |
VIRTIO_BLK_F_SEG_MAX |
VIRTIO_BLK_F_GEOMETRY |
VIRTIO_BLK_F_BLK_SIZE;
?
+ vdev->guest_features[1] = VIRTIO_F_VERSION_1;
+ if (virtio_pci_negotiate()) {
+ panic("Virtio feature negotation failed!");
+ }
Maybe double-check whether VIRTIO_F_VERSION_1 has really been negotiated?
Otherwise, what happens if a user runs QEMU with "-device
virtio-blk-pci,disable-modern=on" ?
Thomas
