kvm tools: Bring VIRTIO_BLK_F_SEG_MAX feature back to virtio blk

commit b764422bb0b46b00b896f6d4538ac3d3dde9e56b
(kvm tools: Add support for multiple virtio-blk)
removed the VIRTIO_BLK_F_SEG_MAX publishment to guest.

There is no reason we should not support it. Just bring it back.

Signed-off-by: Asias He <asias.hejun@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

diff --git a/tools/kvm/virtio/blk.c b/tools/kvm/virtio/blk.c
index 5085f1be35275bdf603b0e9e762b88609551d3f6..1c6b6083182e5a5d4a052e92013ca21b6f4cd0d4 100644 (file)
--- a/tools/kvm/virtio/blk.c
+++ b/tools/kvm/virtio/blk.c
@@ -21,6 +21,10 @@
 #define NUM_VIRT_QUEUES                        1
 
 #define VIRTIO_BLK_QUEUE_SIZE          128
+/*
+ * the header and status consume too entries
+ */
+#define DISK_SEG_MAX                   (VIRTIO_BLK_QUEUE_SIZE - 2)
 
 struct blk_dev_job {
        struct virt_queue               *vq;
@@ -278,11 +282,12 @@ void virtio_blk__init(struct kvm *kvm, struct disk_image *disk)
        blk_dev_base_addr       = IOPORT_VIRTIO_BLK + new_dev_idx * IOPORT_VIRTIO_BLK_SIZE;
 
        *bdev                   = (struct blk_dev) {
-               .mutex                  = PTHREAD_MUTEX_INITIALIZER,
-               .disk                   = disk,
-               .idx                    = new_dev_idx,
-               .blk_config             = (struct virtio_blk_config) {
+               .mutex                          = PTHREAD_MUTEX_INITIALIZER,
+               .disk                           = disk,
+               .idx                            = new_dev_idx,
+               .blk_config                     = (struct virtio_blk_config) {
                        .capacity               = disk->size / SECTOR_SIZE,
+                       .seg_max                = DISK_SEG_MAX,
                },
                .pci_hdr = (struct pci_device_header) {
                        .vendor_id              = PCI_VENDOR_ID_REDHAT_QUMRANET,
@@ -294,6 +299,12 @@ void virtio_blk__init(struct kvm *kvm, struct disk_image *disk)
                        .subsys_id              = PCI_SUBSYSTEM_ID_VIRTIO_BLK,
                        .bar[0]                 = blk_dev_base_addr | PCI_BASE_ADDRESS_SPACE_IO,
                },
+               /*
+                * Note we don't set VIRTIO_BLK_F_GEOMETRY here so the
+                * guest kernel will compute disk geometry by own, the
+                * same applies to VIRTIO_BLK_F_BLK_SIZE
+                */
+               .host_features                  = (1UL << VIRTIO_BLK_F_SEG_MAX),
        };
 
        if (irq__register_device(PCI_DEVICE_ID_VIRTIO_BLK, &dev, &pin, &line) < 0)