From 5eba0404b98294906134c06519c272bfb5f50453 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 27 Jan 2017 16:40:16 +0100 Subject: [PATCH] virtio: use MemoryRegionCache to access descriptors For now, the cache is created on every virtqueue_pop. Later on, direct descriptors will be able to reuse it. Reviewed-by: Stefan Hajnoczi Signed-off-by: Paolo Bonzini Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/virtio/virtio.c | 80 +++++++++++++++++++++---------------------- include/exec/memory.h | 2 ++ 2 files changed, 41 insertions(+), 41 deletions(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 6ce6a2690843..71e41f66b1e7 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; } @@ -436,24 +437,25 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, 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; + MemoryRegionCache vring_desc_cache; + MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID; + int64_t 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); + 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; } while ((rc = virtqueue_num_heads(vq, idx)) > 0) { - void *desc_ptr = vring_desc_ptr; + MemoryRegionCache *desc_cache = &vring_desc_cache; unsigned int num_bufs; VRingDesc desc; unsigned int i; @@ -464,10 +466,9 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, goto err; } - vring_desc_read(vdev, &desc, desc_ptr, i); + vring_desc_read(vdev, &desc, desc_cache, 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; @@ -480,9 +481,10 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, } /* loop over the indirect descriptor table */ - indirect_desc_ptr = address_space_map(vdev->dma_as, desc.addr, - &len, false); - desc_ptr = indirect_desc_ptr; + 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; @@ -490,7 +492,7 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, 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 { @@ -509,16 +511,15 @@ 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 (desc_ptr == indirect_desc_ptr) { - address_space_unmap(vdev->dma_as, desc_ptr, len, false, 0); - indirect_desc_ptr = NULL; + if (desc_cache == &indirect_desc_cache) { + address_space_cache_destroy(&indirect_desc_cache); total_bufs++; } else { total_bufs = num_bufs; @@ -530,10 +531,8 @@ 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); + address_space_cache_destroy(&indirect_desc_cache); + address_space_cache_destroy(&vring_desc_cache); if (in_bytes) { *in_bytes = in_total; } @@ -673,10 +672,10 @@ 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 *vring_desc_ptr; - void *indirect_desc_ptr = NULL; - void *desc_ptr; - hwaddr len; + MemoryRegionCache vring_desc_cache; + MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID; + MemoryRegionCache *desc_cache; + int64_t len; VirtIODevice *vdev = vq->vdev; VirtQueueElement *elem = NULL; unsigned out_num, in_num; @@ -715,15 +714,16 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz) i = head; - len = max * sizeof(VRingDesc); - vring_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); 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); + desc_cache = &vring_desc_cache; + vring_desc_read(vdev, &desc, desc_cache, i); if (desc.flags & VRING_DESC_F_INDIRECT) { if (desc.len % sizeof(VRingDesc)) { virtio_error(vdev, "Invalid size for indirect buffer table"); @@ -731,9 +731,9 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz) } /* 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; + 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 done; @@ -741,7 +741,7 @@ 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 */ @@ -772,7 +772,7 @@ 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) { @@ -795,10 +795,8 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz) 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); + address_space_cache_destroy(&indirect_desc_cache); + address_space_cache_destroy(&vring_desc_cache); return elem; diff --git a/include/exec/memory.h b/include/exec/memory.h index 987f9251c61f..691102317c75 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -1426,6 +1426,8 @@ struct MemoryRegionCache { bool is_write; }; +#define MEMORY_REGION_CACHE_INVALID ((MemoryRegionCache) { .mr = NULL }) + /* address_space_cache_init: prepare for repeated access to a physical * memory region *