Commit f1f9e6c5 authored by Greg Kurz's avatar Greg Kurz Committed by Michael S. Tsirkin
Browse files

vhost: adapt vhost_verify_ring_mappings() to virtio 1 ring layout 



With virtio 1, the vring layout is split in 3 separate regions of
contiguous memory for the descriptor table, the available ring and the
used ring, as opposed with legacy virtio which uses a single region.

In case of memory re-mapping, the code ensures it doesn't affect the
vring mapping. This is done in vhost_verify_ring_mappings() which assumes
the device is legacy.

This patch changes vhost_verify_ring_mappings() to check the mappings of
each part of the vring separately.

This works for legacy mappings as well.

Cc: qemu-stable@nongnu.org
Signed-off-by: default avatarGreg Kurz <groug@kaod.org>
Reviewed-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent cb88ebd7

hw/virtio/vhost.c

+60 −19
Original line number Diff line number Diff line
@@ -421,32 +421,73 @@ static inline void vhost_dev_log_resize(struct vhost_dev *dev, uint64_t size) 
    dev->log_size = size;

}



static int vhost_verify_ring_mappings(struct vhost_dev *dev,



static int vhost_verify_ring_part_mapping(void *part,

                                          uint64_t part_addr,

                                          uint64_t part_size,

                                          uint64_t start_addr,

                                          uint64_t size)

{

    int i;

    int r = 0;



    for (i = 0; !r && i < dev->nvqs; ++i) {

        struct vhost_virtqueue *vq = dev->vqs + i;

    hwaddr l;

    void *p;

    int r = 0;



        if (!ranges_overlap(start_addr, size, vq->ring_phys, vq->ring_size)) {

            continue;

    if (!ranges_overlap(start_addr, size, part_addr, part_size)) {

        return 0;

    }

        l = vq->ring_size;

        p = cpu_physical_memory_map(vq->ring_phys, &l, 1);

        if (!p || l != vq->ring_size) {

            error_report("Unable to map ring buffer for ring %d", i);

    l = part_size;

    p = cpu_physical_memory_map(part_addr, &l, 1);

    if (!p || l != part_size) {

        r = -ENOMEM;

    }

        if (p != vq->ring) {

            error_report("Ring buffer relocated for ring %d", i);

    if (p != part) {

        r = -EBUSY;

    }

    cpu_physical_memory_unmap(p, l, 0, 0);

    return r;

}



static int vhost_verify_ring_mappings(struct vhost_dev *dev,

                                      uint64_t start_addr,

                                      uint64_t size)

{

    int i, j;

    int r = 0;

    const char *part_name[] = {

        "descriptor table",

        "available ring",

        "used ring"

    };



    for (i = 0; i < dev->nvqs; ++i) {

        struct vhost_virtqueue *vq = dev->vqs + i;



        j = 0;

        r = vhost_verify_ring_part_mapping(vq->desc, vq->desc_phys,

                                           vq->desc_size, start_addr, size);

        if (!r) {

            break;

        }



        j++;

        r = vhost_verify_ring_part_mapping(vq->avail, vq->avail_phys,

                                           vq->avail_size, start_addr, size);

        if (!r) {

            break;

        }



        j++;

        r = vhost_verify_ring_part_mapping(vq->used, vq->used_phys,

                                           vq->used_size, start_addr, size);

        if (!r) {

            break;

        }

    }



    if (r == -ENOMEM) {

        error_report("Unable to map %s for ring %d", part_name[j], i);

    } else if (r == -EBUSY) {

        error_report("%s relocated for ring %d", part_name[j], i);

    }

    return r;

}
@@ -860,15 +901,15 @@ static int vhost_virtqueue_start(struct vhost_dev *dev, 
        }

    }



    s = l = virtio_queue_get_desc_size(vdev, idx);

    a = virtio_queue_get_desc_addr(vdev, idx);

    vq->desc_size = s = l = virtio_queue_get_desc_size(vdev, idx);

    vq->desc_phys = a = virtio_queue_get_desc_addr(vdev, idx);

    vq->desc = cpu_physical_memory_map(a, &l, 0);

    if (!vq->desc || l != s) {

        r = -ENOMEM;

        goto fail_alloc_desc;

    }

    s = l = virtio_queue_get_avail_size(vdev, idx);

    a = virtio_queue_get_avail_addr(vdev, idx);

    vq->avail_size = s = l = virtio_queue_get_avail_size(vdev, idx);

    vq->avail_phys = a = virtio_queue_get_avail_addr(vdev, idx);

    vq->avail = cpu_physical_memory_map(a, &l, 0);

    if (!vq->avail || l != s) {

        r = -ENOMEM;

include/hw/virtio/vhost.h

+4 −0
Original line number Diff line number Diff line
@@ -14,6 +14,10 @@ struct vhost_virtqueue { 
    void *avail;

    void *used;

    int num;

    unsigned long long desc_phys;

    unsigned desc_size;

    unsigned long long avail_phys;

    unsigned avail_size;

    unsigned long long used_phys;

    unsigned used_size;

    void *ring;