[RFC,08/10] vhost: send userfault range addresses back to qemu
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Commit Message
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
lib/librte_vhost/vhost_user.c | 48 ++++++++++++++++++++++++++++++++---
1 file changed, 44 insertions(+), 4 deletions(-)
@@ -77,6 +77,11 @@ static const char *vhost_message_str[VHOST_USER_MAX] = {
[VHOST_USER_POSTCOPY_LISTEN] = "VHOST_USER_POSTCOPY_LISTEN",
};
+static int
+send_vhost_reply(int sockfd, struct VhostUserMsg *msg);
+static int
+read_vhost_message(int sockfd, struct VhostUserMsg *msg);
+
static uint64_t
get_blk_size(int fd)
{
@@ -784,7 +789,8 @@ vhost_memory_changed(struct VhostUserMemory *new,
}
static int
-vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *pmsg)
+vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *pmsg,
+ int main_fd)
{
struct virtio_net *dev = *pdev;
struct VhostUserMemory *memory = &pmsg->payload.memory;
@@ -928,10 +934,44 @@ vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *pmsg)
mmap_offset);
if (dev->postcopy_listening) {
+ /*
+ * We haven't a better way right now than sharing
+ * DPDK's virtual address with Qemu, so that Qemu can
+ * retreive the region offset when handling userfaults.
+ */
+ memory->regions[i].userspace_addr =
+ (uint64_t)(uintptr_t)mmap_addr;
+ }
+ }
+ if (dev->postcopy_listening) {
+ /* Send the addresses back to qemu */
+ pmsg->fd_num = 0;
+ send_vhost_reply(main_fd, pmsg);
+
+ /* Wait for qemu to acknolwedge it's got the addresses
+ * we've got to wait before we're allowed to generate faults.
+ */
+ VhostUserMsg ack_msg;
+ if (read_vhost_message(main_fd, &ack_msg) <= 0) {
+ RTE_LOG(ERR, VHOST_CONFIG,
+ "Failed to read qemu ack on postcopy set-mem-table\n");
+ goto err_mmap;
+ }
+ if (ack_msg.request.master != VHOST_USER_SET_MEM_TABLE) {
+ RTE_LOG(ERR, VHOST_CONFIG,
+ "Bad qemu ack on postcopy set-mem-table (%d)\n",
+ ack_msg.request.master);
+ goto err_mmap;
+ }
+
+ /* Now userfault register and we can use the memory */
+ for (i = 0; i < memory->nregions; i++) {
+ reg = &dev->mem->regions[i];
struct uffdio_register reg_struct;
- reg_struct.range.start = (uint64_t)(uintptr_t)mmap_addr;
- reg_struct.range.len = mmap_size;
+ reg_struct.range.start =
+ (uint64_t)(uintptr_t)reg->mmap_addr;
+ reg_struct.range.len = reg->mmap_size;
reg_struct.mode = UFFDIO_REGISTER_MODE_MISSING;
if (ioctl(dev->postcopy_ufd, UFFDIO_REGISTER,
@@ -1744,7 +1784,7 @@ vhost_user_msg_handler(int vid, int fd)
break;
case VHOST_USER_SET_MEM_TABLE:
- ret = vhost_user_set_mem_table(&dev, &msg);
+ ret = vhost_user_set_mem_table(&dev, &msg, fd);
break;
case VHOST_USER_SET_LOG_BASE: