mirror of https://gitee.com/openkylin/qemu.git
Use the DMA api to map virtio elements.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6904 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
aliguori
parent
d28a1b6ec6
commit
26b258e138
97
hw/virtio.c
97
hw/virtio.c
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@ -16,8 +16,6 @@
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#include "virtio.h"
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#include "sysemu.h"
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//#define VIRTIO_ZERO_COPY
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/* from Linux's linux/virtio_pci.h */
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/* A 32-bit r/o bitmask of the features supported by the host */
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@ -113,43 +111,6 @@ struct VirtQueue
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#define VIRTIO_PCI_QUEUE_MAX 16
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/* virt queue functions */
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#ifdef VIRTIO_ZERO_COPY
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static void *virtio_map_gpa(target_phys_addr_t addr, size_t size)
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{
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ram_addr_t off;
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target_phys_addr_t addr1;
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off = cpu_get_physical_page_desc(addr);
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if ((off & ~TARGET_PAGE_MASK) != IO_MEM_RAM) {
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fprintf(stderr, "virtio DMA to IO ram\n");
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exit(1);
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}
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off = (off & TARGET_PAGE_MASK) | (addr & ~TARGET_PAGE_MASK);
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for (addr1 = addr + TARGET_PAGE_SIZE;
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addr1 < TARGET_PAGE_ALIGN(addr + size);
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addr1 += TARGET_PAGE_SIZE) {
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ram_addr_t off1;
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off1 = cpu_get_physical_page_desc(addr1);
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if ((off1 & ~TARGET_PAGE_MASK) != IO_MEM_RAM) {
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fprintf(stderr, "virtio DMA to IO ram\n");
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exit(1);
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}
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off1 = (off1 & TARGET_PAGE_MASK) | (addr1 & ~TARGET_PAGE_MASK);
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if (off1 != (off + (addr1 - addr))) {
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fprintf(stderr, "discontigous virtio memory\n");
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exit(1);
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}
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}
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return phys_ram_base + off;
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}
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#endif
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static void virtqueue_init(VirtQueue *vq, target_phys_addr_t pa)
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{
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vq->vring.desc = pa;
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@ -274,35 +235,22 @@ void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
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unsigned int offset;
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int i;
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#ifndef VIRTIO_ZERO_COPY
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for (i = 0; i < elem->out_num; i++)
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qemu_free(elem->out_sg[i].iov_base);
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#endif
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offset = 0;
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for (i = 0; i < elem->in_num; i++) {
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size_t size = MIN(len - offset, elem->in_sg[i].iov_len);
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#ifdef VIRTIO_ZERO_COPY
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if (size) {
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ram_addr_t addr = (uint8_t *)elem->in_sg[i].iov_base - phys_ram_base;
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ram_addr_t off;
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cpu_physical_memory_unmap(elem->in_sg[i].iov_base,
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elem->in_sg[i].iov_len,
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1, size);
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for (off = 0; off < size; off += TARGET_PAGE_SIZE)
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cpu_physical_memory_set_dirty(addr + off);
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}
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#else
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if (size)
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cpu_physical_memory_write(elem->in_addr[i],
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elem->in_sg[i].iov_base,
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size);
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qemu_free(elem->in_sg[i].iov_base);
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#endif
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offset += size;
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offset += elem->in_sg[i].iov_len;
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}
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for (i = 0; i < elem->out_num; i++)
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cpu_physical_memory_unmap(elem->out_sg[i].iov_base,
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elem->out_sg[i].iov_len,
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0, elem->out_sg[i].iov_len);
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idx = (idx + vring_used_idx(vq)) % vq->vring.num;
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/* Get a pointer to the next entry in the used ring. */
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@ -414,6 +362,7 @@ int virtqueue_avail_bytes(VirtQueue *vq, int in_bytes, int out_bytes)
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int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem)
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{
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unsigned int i, head;
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target_phys_addr_t len;
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if (!virtqueue_num_heads(vq, vq->last_avail_idx))
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return 0;
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@ -424,37 +373,23 @@ int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem)
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i = head = virtqueue_get_head(vq, vq->last_avail_idx++);
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do {
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struct iovec *sg;
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int is_write = 0;
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if (vring_desc_flags(vq, i) & VRING_DESC_F_WRITE) {
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elem->in_addr[elem->in_num] = vring_desc_addr(vq, i);
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sg = &elem->in_sg[elem->in_num++];
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is_write = 1;
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} else
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sg = &elem->out_sg[elem->out_num++];
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/* Grab the first descriptor, and check it's OK. */
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sg->iov_len = vring_desc_len(vq, i);
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len = sg->iov_len;
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#ifdef VIRTIO_ZERO_COPY
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sg->iov_base = virtio_map_gpa(vring_desc_addr(vq, i), sg->iov_len);
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#else
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/* cap individual scatter element size to prevent unbounded allocations
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of memory from the guest. Practically speaking, no virtio driver
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will ever pass more than a page in each element. We set the cap to
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be 2MB in case for some reason a large page makes it way into the
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sg list. When we implement a zero copy API, this limitation will
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disappear */
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if (sg->iov_len > (2 << 20))
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sg->iov_len = 2 << 20;
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sg->iov_base = cpu_physical_memory_map(vring_desc_addr(vq, i), &len, is_write);
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sg->iov_base = qemu_malloc(sg->iov_len);
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if (!(vring_desc_flags(vq, i) & VRING_DESC_F_WRITE)) {
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cpu_physical_memory_read(vring_desc_addr(vq, i),
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sg->iov_base,
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sg->iov_len);
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}
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#endif
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if (sg->iov_base == NULL) {
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fprintf(stderr, "Invalid mapping\n");
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if (sg->iov_base == NULL || len != sg->iov_len) {
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fprintf(stderr, "virtio: trying to map MMIO memory\n");
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exit(1);
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}
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