On Thu, Aug 24, 2017 at 08:27:14PM +0100, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
>
> We need a better way, but at the moment we need the address of the
> mappings sent back to qemu so it can interpret the messages on the
> userfaultfd it reads.
>
> Note: We don't ask for the default 'ack' reply since we've got our own.
>
> Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> ---
> contrib/libvhost-user/libvhost-user.c | 15 ++++++++-
> docs/interop/vhost-user.txt | 6 ++++
> hw/virtio/trace-events | 1 +
> hw/virtio/vhost-user.c | 57
> ++++++++++++++++++++++++++++++++++-
> 4 files changed, 77 insertions(+), 2 deletions(-)
>
> diff --git a/contrib/libvhost-user/libvhost-user.c
> b/contrib/libvhost-user/libvhost-user.c
> index e6ab059a03..5ec54f7d60 100644
> --- a/contrib/libvhost-user/libvhost-user.c
> +++ b/contrib/libvhost-user/libvhost-user.c
> @@ -477,13 +477,26 @@ vu_set_mem_table_exec(VuDev *dev, VhostUserMsg *vmsg)
> DPRINT("%s: region %d: Registered userfault for %llx + %llx\n",
> __func__, i, reg_struct.range.start,
> reg_struct.range.len);
> /* TODO: Stash 'zero' support flags somewhere */
> - /* TODO: Get address back to QEMU */
>
> + /* TODO: We need to find a way for the qemu not to see the
> virtual
> + * addresses of the clients, so as to keep better separation.
> + */
> + /* Return the address to QEMU so that it can translate the ufd
> + * fault addresses back.
> + */
> + msg_region->userspace_addr = (uintptr_t)(mmap_addr +
> +
> dev_region->mmap_offset);
> }
>
> close(vmsg->fds[i]);
> }
>
> + if (dev->postcopy_listening) {
> + /* Need to return the addresses - send the updated message back */
> + vmsg->fd_num = 0;
> + return true;
> + }
> +
> return false;
> }
>
> diff --git a/docs/interop/vhost-user.txt b/docs/interop/vhost-user.txt
> index 73c3dd74db..b2a548c94d 100644
> --- a/docs/interop/vhost-user.txt
> +++ b/docs/interop/vhost-user.txt
> @@ -413,12 +413,18 @@ Master message types
> Id: 5
> Equivalent ioctl: VHOST_SET_MEM_TABLE
> Master payload: memory regions description
> + Slave payload: (postcopy only) memory regions description
>
> Sets the memory map regions on the slave so it can translate the vring
> addresses. In the ancillary data there is an array of file descriptors
> for each memory mapped region. The size and ordering of the fds matches
> the number and ordering of memory regions.
>
> + When postcopy-listening has been received, SET_MEM_TABLE replies with
> + the bases of the memory mapped regions to the master. It must have
> mmap'd
> + the regions and enabled userfaultfd on them. Note NEED_REPLY_MASK
> + is not set in this case.
> +
> * VHOST_USER_SET_LOG_BASE
>
> Id: 6
> diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
> index f736c7c84f..63fd4a79cf 100644
> --- a/hw/virtio/trace-events
> +++ b/hw/virtio/trace-events
> @@ -2,6 +2,7 @@
>
> # hw/virtio/vhost-user.c
> vhost_user_postcopy_listen(void) ""
> +vhost_user_set_mem_table_postcopy(uint64_t client_addr, uint64_t qhva, int
> reply_i, int region_i) "client:0x%"PRIx64" for hva: 0x%"PRIx64" reply %d
> region %d"
>
> # hw/virtio/virtio.c
> virtqueue_alloc_element(void *elem, size_t sz, unsigned in_num, unsigned
> out_num) "elem %p size %zd in_num %u out_num %u"
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index 9178271ab2..2e4eb0864a 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -19,6 +19,7 @@
> #include "qemu/sockets.h"
> #include "migration/migration.h"
> #include "migration/postcopy-ram.h"
> +#include "trace.h"
>
> #include <sys/ioctl.h>
> #include <sys/socket.h>
> @@ -133,6 +134,7 @@ struct vhost_user {
> int slave_fd;
> NotifierWithReturn postcopy_notifier;
> struct PostCopyFD postcopy_fd;
> + uint64_t postcopy_client_bases[VHOST_MEMORY_MAX_NREGIONS];
> };
>
> static bool ioeventfd_enabled(void)
> @@ -300,11 +302,13 @@ static int vhost_user_set_log_base(struct vhost_dev
> *dev, uint64_t base,
> static int vhost_user_set_mem_table(struct vhost_dev *dev,
> struct vhost_memory *mem)
> {
> + struct vhost_user *u = dev->opaque;
> int fds[VHOST_MEMORY_MAX_NREGIONS];
> int i, fd;
> size_t fd_num = 0;
> bool reply_supported = virtio_has_feature(dev->protocol_features,
> -
> VHOST_USER_PROTOCOL_F_REPLY_ACK);
> + VHOST_USER_PROTOCOL_F_REPLY_ACK) &&
> + !u->postcopy_fd.handler;
(indent)
>
> VhostUserMsg msg = {
> .request = VHOST_USER_SET_MEM_TABLE,
> @@ -350,6 +354,57 @@ static int vhost_user_set_mem_table(struct vhost_dev
> *dev,
> return -1;
> }
>
> + if (u->postcopy_fd.handler) {
It seems that after this handler is set, we never clean it up. Do we
need to unset it somewhere? (maybe vhost_user_postcopy_end?)
> + VhostUserMsg msg_reply;
> + int region_i, reply_i;
> + if (vhost_user_read(dev, &msg_reply) < 0) {
> + return -1;
> + }
> +
> + if (msg_reply.request != VHOST_USER_SET_MEM_TABLE) {
> + error_report("%s: Received unexpected msg type."
> + "Expected %d received %d", __func__,
> + VHOST_USER_SET_MEM_TABLE, msg_reply.request);
> + return -1;
> + }
> + /* We're using the same structure, just reusing one of the
> + * fields, so it should be the same size.
> + */
> + if (msg_reply.size != msg.size) {
> + error_report("%s: Unexpected size for postcopy reply "
> + "%d vs %d", __func__, msg_reply.size, msg.size);
> + return -1;
> + }
> +
> + memset(u->postcopy_client_bases, 0,
> + sizeof(uint64_t) * VHOST_MEMORY_MAX_NREGIONS);
> +
> + /* They're in the same order as the regions that were sent
> + * but some of the regions were skipped (above) if they
> + * didn't have fd's
> + */
> + for (reply_i = 0, region_i = 0;
> + region_i < dev->mem->nregions;
> + region_i++) {
> + if (reply_i < fd_num &&
> + msg_reply.payload.memory.regions[region_i].guest_phys_addr ==
^^^^^^^^
should this be reply_i?
(And maybe we can use pointers for the regions for better readability?)
> + dev->mem->regions[region_i].guest_phys_addr) {
> + u->postcopy_client_bases[region_i] =
> + msg_reply.payload.memory.regions[reply_i].userspace_addr;
> + trace_vhost_user_set_mem_table_postcopy(
> + msg_reply.payload.memory.regions[reply_i].userspace_addr,
> + msg.payload.memory.regions[reply_i].userspace_addr,
> + reply_i, region_i);
> + reply_i++;
> + }
> + }
> + if (reply_i != fd_num) {
> + error_report("%s: postcopy reply not fully consumed "
> + "%d vs %zd",
> + __func__, reply_i, fd_num);
> + return -1;
> + }
> + }
> if (reply_supported) {
> return process_message_reply(dev, &msg);
> }
> --
> 2.13.5
>
--
Peter Xu
