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[Qemu-devel] [PATCH 4/7] virtio: use MemoryRegionCache to access descrip
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 4/7] virtio: use MemoryRegionCache to access descriptors |
Date: |
Fri, 20 Jan 2017 18:07:54 +0100 |
For now, the cache is created on every virtqueue_pop. Later on,
direct descriptors will be able to reuse it.
Signed-off-by: Paolo Bonzini <address@hidden>
---
hw/virtio/virtio.c | 91 ++++++++++++++++++++++++++++++------------------------
1 file changed, 50 insertions(+), 41 deletions(-)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 7a49f2e..52673d1 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -120,9 +120,10 @@ void virtio_queue_update_rings(VirtIODevice *vdev, int n)
}
static void vring_desc_read(VirtIODevice *vdev, VRingDesc *desc,
- uint8_t *desc_ptr, int i)
+ MemoryRegionCache *cache, int i)
{
- memcpy(desc, desc_ptr + i * sizeof(VRingDesc), sizeof(VRingDesc));
+ address_space_read_cached(cache, i * sizeof(VRingDesc),
+ desc, sizeof(VRingDesc));
virtio_tswap64s(vdev, &desc->addr);
virtio_tswap32s(vdev, &desc->len);
virtio_tswap16s(vdev, &desc->flags);
@@ -407,7 +408,7 @@ enum {
};
static int virtqueue_read_next_desc(VirtIODevice *vdev, VRingDesc *desc,
- void *desc_ptr, unsigned int max,
+ MemoryRegionCache *desc_cache, unsigned
int max,
unsigned int *next)
{
/* If this descriptor says it doesn't chain, we're done. */
@@ -425,7 +426,7 @@ static int virtqueue_read_next_desc(VirtIODevice *vdev,
VRingDesc *desc,
return VIRTQUEUE_READ_DESC_ERROR;
}
- vring_desc_read(vdev, desc, desc_ptr, *next);
+ vring_desc_read(vdev, desc, desc_cache, *next);
return VIRTQUEUE_READ_DESC_MORE;
}
@@ -434,39 +435,40 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned
int *in_bytes,
unsigned max_in_bytes, unsigned max_out_bytes)
{
VirtIODevice *vdev = vq->vdev;
- unsigned int idx;
+ unsigned int max, idx;
unsigned int total_bufs, in_total, out_total;
- void *desc_ptr = NULL;
- hwaddr len = 0;
+ MemoryRegionCache *desc_cache = NULL;
+ MemoryRegionCache vring_desc_cache;
+ MemoryRegionCache indirect_desc_cache;
+ int64_t len = 0;
int rc;
idx = vq->last_avail_idx;
+ max = vq->vring.num;
+ len = address_space_cache_init(&vring_desc_cache, vdev->dma_as,
+ vq->vring.desc, max * sizeof(VRingDesc),
+ false);
+ if (len < max * sizeof(VRingDesc)) {
+ virtio_error(vdev, "Cannot map descriptor ring");
+ goto err;
+ }
total_bufs = in_total = out_total = 0;
while ((rc = virtqueue_num_heads(vq, idx)) > 0) {
- unsigned int max, num_bufs, indirect = 0;
+ unsigned int num_bufs;
VRingDesc desc;
unsigned int i;
- max = vq->vring.num;
num_bufs = total_bufs;
if (!virtqueue_get_head(vq, idx++, &i)) {
goto err;
}
- len = max * sizeof(VRingDesc);
- 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;
- }
-
- vring_desc_read(vdev, &desc, desc_ptr, i);
+ desc_cache = &vring_desc_cache;
+ vring_desc_read(vdev, &desc, desc_cache, i);
if (desc.flags & VRING_DESC_F_INDIRECT) {
- address_space_unmap(vdev->dma_as, desc_ptr, len, false, 0);
- len = desc.len;
if (desc.len % sizeof(VRingDesc)) {
virtio_error(vdev, "Invalid size for indirect buffer table");
goto err;
@@ -479,16 +481,18 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned
int *in_bytes,
}
/* loop over the indirect descriptor table */
- desc_ptr = address_space_map(vdev->dma_as, desc.addr, &len, false);
+ len = address_space_cache_init(&indirect_desc_cache,
+ vdev->dma_as,
+ desc.addr, desc.len, false);
+ desc_cache = &indirect_desc_cache;
if (len < desc.len) {
virtio_error(vdev, "Cannot map indirect buffer");
goto err;
}
- indirect = 1;
max = desc.len / sizeof(VRingDesc);
num_bufs = i = 0;
- vring_desc_read(vdev, &desc, desc_ptr, i);
+ vring_desc_read(vdev, &desc, desc_cache, i);
}
do {
@@ -507,17 +511,19 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned
int *in_bytes,
goto done;
}
- rc = virtqueue_read_next_desc(vdev, &desc, desc_ptr, max, &i);
+ rc = virtqueue_read_next_desc(vdev, &desc, desc_cache, 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_cache == &indirect_desc_cache) {
+ address_space_cache_destroy(&indirect_desc_cache);
total_bufs++;
+ } else {
+ total_bufs = num_bufs;
+ }
}
if (rc < 0) {
@@ -525,9 +531,7 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int
*in_bytes,
}
done:
- if (desc_ptr) {
- address_space_unmap(vdev->dma_as, desc_ptr, len, false, 0);
- }
+ address_space_cache_destroy(&vring_desc_cache);
if (in_bytes) {
*in_bytes = in_total;
}
@@ -667,8 +671,10 @@ 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;
- void *desc_ptr = NULL;
- hwaddr len;
+ MemoryRegionCache *desc_cache = NULL;
+ MemoryRegionCache indirect_desc_cache;
+ MemoryRegionCache vring_desc_cache;
+ int64_t len;
VirtIODevice *vdev = vq->vdev;
VirtQueueElement *elem = NULL;
unsigned out_num, in_num;
@@ -707,24 +713,26 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz)
i = head;
- len = max * sizeof(VRingDesc);
- desc_ptr = address_space_map(vdev->dma_as, vq->vring.desc, &len, false);
+ len = address_space_cache_init(&vring_desc_cache, vdev->dma_as,
+ vq->vring.desc, max * sizeof(VRingDesc),
+ false);
+ desc_cache = &vring_desc_cache;
if (len < max * sizeof(VRingDesc)) {
virtio_error(vdev, "Cannot map descriptor ring");
return NULL;
}
- vring_desc_read(vdev, &desc, desc_ptr, i);
+ vring_desc_read(vdev, &desc, desc_cache, i);
if (desc.flags & VRING_DESC_F_INDIRECT) {
- address_space_unmap(vdev->dma_as, desc_ptr, len, false, 0);
if (desc.len % sizeof(VRingDesc)) {
virtio_error(vdev, "Invalid size for indirect buffer table");
return NULL;
}
/* loop over the indirect descriptor table */
- len = desc.len;
- desc_ptr = address_space_map(vdev->dma_as, desc.addr, &len, false);
+ len = address_space_cache_init(&indirect_desc_cache, vdev->dma_as,
+ desc.addr, desc.len, false);
+ desc_cache = &indirect_desc_cache;
if (len < desc.len) {
virtio_error(vdev, "Cannot map indirect buffer");
return NULL;
@@ -732,7 +740,7 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz)
max = desc.len / sizeof(VRingDesc);
i = 0;
- vring_desc_read(vdev, &desc, desc_ptr, i);
+ vring_desc_read(vdev, &desc, desc_cache, i);
}
/* Collect all the descriptors */
@@ -763,7 +771,7 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz)
goto err_undo_map;
}
- rc = virtqueue_read_next_desc(vdev, &desc, desc_ptr, max, &i);
+ rc = virtqueue_read_next_desc(vdev, &desc, desc_cache, max, &i);
} while (rc == VIRTQUEUE_READ_DESC_MORE);
if (rc == VIRTQUEUE_READ_DESC_ERROR) {
@@ -786,9 +794,10 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz)
trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num);
done:
- if (desc_ptr) {
- address_space_unmap(vdev->dma_as, desc_ptr, len, false, 0);
+ if (desc_cache == &indirect_desc_cache) {
+ address_space_cache_destroy(&indirect_desc_cache);
}
+ address_space_cache_destroy(&vring_desc_cache);
return elem;
--
2.9.3
- [Qemu-devel] [PATCH 0/7] virtio: use MemoryRegionCache for descriptors and rings, Paolo Bonzini, 2017/01/20
- [Qemu-devel] [PATCH 2/7] virtio: add virtio_*_phys_cached, Paolo Bonzini, 2017/01/20
- [Qemu-devel] [PATCH 1/7] virtio: make virtio_should_notify static, Paolo Bonzini, 2017/01/20
- [Qemu-devel] [PATCH 4/7] virtio: use MemoryRegionCache to access descriptors,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 3/7] virtio: use address_space_map/unmap to access descriptors, Paolo Bonzini, 2017/01/20
- [Qemu-devel] [PATCH 5/7] virtio: add MemoryListener to cache ring translations, Paolo Bonzini, 2017/01/20
- [Qemu-devel] [PATCH 6/7] virtio: use VRingMemoryRegionCaches for descriptor ring, Paolo Bonzini, 2017/01/20
- [Qemu-devel] [PATCH 7/7] virtio: use VRingMemoryRegionCaches for avail and used rings, Paolo Bonzini, 2017/01/20