Commit 9796d0ac authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Michael S. Tsirkin
Browse files

virtio: use address_space_map/unmap to access descriptors 



This makes little difference, but it makes the code change smaller
for the next patch that introduces MemoryRegionCache.  This is
because map/unmap are similar to MemoryRegionCache init/destroy.

Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent e6a830d6

hw/virtio/virtio.c

+75 −28
Original line number Diff line number Diff line
@@ -120,10 +120,9 @@ void virtio_queue_update_rings(VirtIODevice *vdev, int n) 
}



static void vring_desc_read(VirtIODevice *vdev, VRingDesc *desc,

                            hwaddr desc_pa, int i)

                            uint8_t *desc_ptr, int i)

{

    address_space_read(vdev->dma_as, desc_pa + i * sizeof(VRingDesc),

                       MEMTXATTRS_UNSPECIFIED, (void *)desc, sizeof(VRingDesc));

    memcpy(desc, desc_ptr + i * sizeof(VRingDesc), sizeof(VRingDesc));

    virtio_tswap64s(vdev, &desc->addr);

    virtio_tswap32s(vdev, &desc->len);

    virtio_tswap16s(vdev, &desc->flags);
@@ -408,7 +407,7 @@ enum { 
};



static int virtqueue_read_next_desc(VirtIODevice *vdev, VRingDesc *desc,

                                    hwaddr desc_pa, unsigned int max,

                                    void *desc_ptr, unsigned int max,

                                    unsigned int *next)

{

    /* If this descriptor says it doesn't chain, we're done. */
@@ -426,7 +425,7 @@ static int virtqueue_read_next_desc(VirtIODevice *vdev, VRingDesc *desc, 
        return VIRTQUEUE_READ_DESC_ERROR;

    }



    vring_desc_read(vdev, desc, desc_pa, *next);

    vring_desc_read(vdev, desc, desc_ptr, *next);

    return VIRTQUEUE_READ_DESC_MORE;

}
@@ -434,31 +433,41 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, 
                               unsigned int *out_bytes,

                               unsigned max_in_bytes, unsigned max_out_bytes)

{

    unsigned int idx;

    VirtIODevice *vdev = vq->vdev;

    unsigned int max, idx;

    unsigned int total_bufs, in_total, out_total;

    void *vring_desc_ptr;

    void *indirect_desc_ptr = NULL;

    hwaddr len = 0;

    int rc;



    idx = vq->last_avail_idx;



    total_bufs = in_total = out_total = 0;



    max = vq->vring.num;

    len = max * sizeof(VRingDesc);

    vring_desc_ptr = address_space_map(vdev->dma_as, vq->vring.desc, &len, false);

    if (len < max * sizeof(VRingDesc)) {

        virtio_error(vdev, "Cannot map descriptor ring");

        goto err;

    }



    while ((rc = virtqueue_num_heads(vq, idx)) > 0) {

        VirtIODevice *vdev = vq->vdev;

        unsigned int max, num_bufs, indirect = 0;

        void *desc_ptr = vring_desc_ptr;

        unsigned int num_bufs;

        VRingDesc desc;

        hwaddr desc_pa;

        unsigned int i;



        max = vq->vring.num;

        num_bufs = total_bufs;



        if (!virtqueue_get_head(vq, idx++, &i)) {

            goto err;

        }



        desc_pa = vq->vring.desc;

        vring_desc_read(vdev, &desc, desc_pa, i);

        vring_desc_read(vdev, &desc, desc_ptr, i);



        if (desc.flags & VRING_DESC_F_INDIRECT) {

            len = desc.len;

            if (desc.len % sizeof(VRingDesc)) {

                virtio_error(vdev, "Invalid size for indirect buffer table");

                goto err;
@@ -471,11 +480,17 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, 
            }



            /* loop over the indirect descriptor table */

            indirect = 1;

            indirect_desc_ptr = address_space_map(vdev->dma_as, desc.addr,

                                                  &len, false);

            desc_ptr = indirect_desc_ptr;

            if (len < desc.len) {

                virtio_error(vdev, "Cannot map indirect buffer");

                goto err;

            }



            max = desc.len / sizeof(VRingDesc);

            desc_pa = desc.addr;

            num_bufs = i = 0;

            vring_desc_read(vdev, &desc, desc_pa, i);

            vring_desc_read(vdev, &desc, desc_ptr, i);

        }



        do {
@@ -494,17 +509,20 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, 
                goto done;

            }



            rc = virtqueue_read_next_desc(vdev, &desc, desc_pa, max, &i);

            rc = virtqueue_read_next_desc(vdev, &desc, desc_ptr, max, &i);

        } while (rc == VIRTQUEUE_READ_DESC_MORE);



        if (rc == VIRTQUEUE_READ_DESC_ERROR) {

            goto err;

        }



        if (!indirect)

            total_bufs = num_bufs;

        else

        if (desc_ptr == indirect_desc_ptr) {

            address_space_unmap(vdev->dma_as, desc_ptr, len, false, 0);

            indirect_desc_ptr = NULL;

            total_bufs++;

        } else {

            total_bufs = num_bufs;

        }

    }



    if (rc < 0) {
@@ -512,6 +530,10 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, 
    }



done:

    if (indirect_desc_ptr) {

        address_space_unmap(vdev->dma_as, indirect_desc_ptr, len, false, 0);

    }

    address_space_unmap(vdev->dma_as, vring_desc_ptr, len, false, 0);

    if (in_bytes) {

        *in_bytes = in_total;

    }
@@ -651,9 +673,12 @@ static void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_nu 
void *virtqueue_pop(VirtQueue *vq, size_t sz)

{

    unsigned int i, head, max;

    hwaddr desc_pa = vq->vring.desc;

    void *vring_desc_ptr;

    void *indirect_desc_ptr = NULL;

    void *desc_ptr;

    hwaddr len;

    VirtIODevice *vdev = vq->vdev;

    VirtQueueElement *elem;

    VirtQueueElement *elem = NULL;

    unsigned out_num, in_num;

    hwaddr addr[VIRTQUEUE_MAX_SIZE];

    struct iovec iov[VIRTQUEUE_MAX_SIZE];
@@ -689,18 +714,34 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz) 
    }



    i = head;

    vring_desc_read(vdev, &desc, desc_pa, i);



    len = max * sizeof(VRingDesc);

    vring_desc_ptr = address_space_map(vdev->dma_as, vq->vring.desc, &len, false);

    if (len < max * sizeof(VRingDesc)) {

        virtio_error(vdev, "Cannot map descriptor ring");

        goto done;

    }



    desc_ptr = vring_desc_ptr;

    vring_desc_read(vdev, &desc, desc_ptr, i);

    if (desc.flags & VRING_DESC_F_INDIRECT) {

        if (desc.len % sizeof(VRingDesc)) {

            virtio_error(vdev, "Invalid size for indirect buffer table");

            return NULL;

            goto done;

        }



        /* loop over the indirect descriptor table */

        len = desc.len;

        indirect_desc_ptr = address_space_map(vdev->dma_as, desc.addr, &len, false);

        desc_ptr = indirect_desc_ptr;

        if (len < desc.len) {

            virtio_error(vdev, "Cannot map indirect buffer");

            goto done;

        }



        max = desc.len / sizeof(VRingDesc);

        desc_pa = desc.addr;

        i = 0;

        vring_desc_read(vdev, &desc, desc_pa, i);

        vring_desc_read(vdev, &desc, desc_ptr, i);

    }



    /* Collect all the descriptors */
@@ -731,7 +772,7 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz) 
            goto err_undo_map;

        }



        rc = virtqueue_read_next_desc(vdev, &desc, desc_pa, max, &i);

        rc = virtqueue_read_next_desc(vdev, &desc, desc_ptr, max, &i);

    } while (rc == VIRTQUEUE_READ_DESC_MORE);



    if (rc == VIRTQUEUE_READ_DESC_ERROR) {
@@ -753,11 +794,17 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz) 
    vq->inuse++;



    trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num);

done:

    if (indirect_desc_ptr) {

        address_space_unmap(vdev->dma_as, indirect_desc_ptr, len, false, 0);

    }

    address_space_unmap(vdev->dma_as, vring_desc_ptr, len, false, 0);



    return elem;



err_undo_map:

    virtqueue_undo_map_desc(out_num, in_num, iov);

    return NULL;

    goto done;

}



/* virtqueue_drop_all: