[Qemu-devel] [PATCH v6 12/29] postcopy+vhost-user: Split set_mem_table for postcopy

[Dr. David Alan Gilbert (git)]

From: "Dr. David Alan Gilbert" <address@hidden>

Split the set_mem_table routines in both qemu and libvhost-user
because the postcopy versions are going to be quite different
once changes in the later patches are added. However, this patch
doesn't produce any functional change, just the split.

Signed-off-by: Dr. David Alan Gilbert <address@hidden>
Reviewed-by: Marc-André Lureau <address@hidden>
---
 contrib/libvhost-user/libvhost-user.c | 53 ++++++++++++++++++++++++++++++++++
 hw/virtio/vhost-user.c                | 54 +++++++++++++++++++++++++++++++++++
 2 files changed, 107 insertions(+)

diff --git a/contrib/libvhost-user/libvhost-user.c 
b/contrib/libvhost-user/libvhost-user.c
index e53b1953df..b2de8ed0a8 100644
--- a/contrib/libvhost-user/libvhost-user.c
+++ b/contrib/libvhost-user/libvhost-user.c
@@ -448,6 +448,55 @@ vu_reset_device_exec(VuDev *dev, VhostUserMsg *vmsg)
     return false;
 }
 
+static bool
+vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
+{
+    int i;
+    VhostUserMemory *memory = &vmsg->payload.memory;
+    dev->nregions = memory->nregions;
+    /* TODO: Postcopy specific code */
+    DPRINT("Nregions: %d\n", memory->nregions);
+    for (i = 0; i < dev->nregions; i++) {
+        void *mmap_addr;
+        VhostUserMemoryRegion *msg_region = &memory->regions[i];
+        VuDevRegion *dev_region = &dev->regions[i];
+
+        DPRINT("Region %d\n", i);
+        DPRINT("    guest_phys_addr: 0x%016"PRIx64"\n",
+               msg_region->guest_phys_addr);
+        DPRINT("    memory_size:     0x%016"PRIx64"\n",
+               msg_region->memory_size);
+        DPRINT("    userspace_addr   0x%016"PRIx64"\n",
+               msg_region->userspace_addr);
+        DPRINT("    mmap_offset      0x%016"PRIx64"\n",
+               msg_region->mmap_offset);
+
+        dev_region->gpa = msg_region->guest_phys_addr;
+        dev_region->size = msg_region->memory_size;
+        dev_region->qva = msg_region->userspace_addr;
+        dev_region->mmap_offset = msg_region->mmap_offset;
+
+        /* We don't use offset argument of mmap() since the
+         * mapped address has to be page aligned, and we use huge
+         * pages.  */
+        mmap_addr = mmap(0, dev_region->size + dev_region->mmap_offset,
+                         PROT_READ | PROT_WRITE, MAP_SHARED,
+                         vmsg->fds[i], 0);
+
+        if (mmap_addr == MAP_FAILED) {
+            vu_panic(dev, "region mmap error: %s", strerror(errno));
+        } else {
+            dev_region->mmap_addr = (uint64_t)(uintptr_t)mmap_addr;
+            DPRINT("    mmap_addr:       0x%016"PRIx64"\n",
+                   dev_region->mmap_addr);
+        }
+
+        close(vmsg->fds[i]);
+    }
+
+    return false;
+}
+
 static bool
 vu_set_mem_table_exec(VuDev *dev, VhostUserMsg *vmsg)
 {
@@ -464,6 +513,10 @@ vu_set_mem_table_exec(VuDev *dev, VhostUserMsg *vmsg)
     }
     dev->nregions = memory->nregions;
 
+    if (dev->postcopy_listening) {
+        return vu_set_mem_table_exec_postcopy(dev, vmsg);
+    }
+
     DPRINT("Nregions: %d\n", memory->nregions);
     for (i = 0; i < dev->nregions; i++) {
         void *mmap_addr;
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 660183d23d..060a339914 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -374,14 +374,68 @@ static int vhost_user_prepare_msg(struct vhost_dev *dev, 
VhostUserMemory *mem,
     return 0;
 }
 
+static int vhost_user_set_mem_table_postcopy(struct vhost_dev *dev,
+                                             struct vhost_memory *mem)
+{
+    int fds[VHOST_MEMORY_MAX_NREGIONS];
+    size_t fd_num;
+    bool reply_supported = virtio_has_feature(dev->protocol_features,
+                                              VHOST_USER_PROTOCOL_F_REPLY_ACK);
+    /* TODO: Add actual postcopy differences */
+    VhostUserMsg msg = {
+        .hdr.request = VHOST_USER_SET_MEM_TABLE,
+        .hdr.flags = VHOST_USER_VERSION,
+    };
+
+    if (reply_supported) {
+        msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK;
+    }
+
+    if (vhost_user_prepare_msg(dev, &msg.payload.memory, fds) < 0) {
+        error_report("Failed preparing vhost-user memory table msg");
+        return -1;
+    }
+
+    fd_num = msg.payload.memory.nregions;
+
+    if (!fd_num) {
+        error_report("Failed initializing vhost-user memory map, "
+                     "consider using -object memory-backend-file share=on");
+        return -1;
+    }
+
+    msg.hdr.size = sizeof(msg.payload.memory.nregions);
+    msg.hdr.size += sizeof(msg.payload.memory.padding);
+    msg.hdr.size += fd_num * sizeof(VhostUserMemoryRegion);
+
+    if (vhost_user_write(dev, &msg, fds, fd_num) < 0) {
+        return -1;
+    }
+
+    if (reply_supported) {
+        return process_message_reply(dev, &msg);
+    }
+
+    return 0;
+}
+
 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];
     size_t fd_num;
+    bool do_postcopy = u->postcopy_listen && u->postcopy_fd.handler;
     bool reply_supported = virtio_has_feature(dev->protocol_features,
                                               VHOST_USER_PROTOCOL_F_REPLY_ACK);
 
+    if (do_postcopy) {
+        /* Postcopy has enough differences that it's best done in it's own
+         * version
+         */
+        return vhost_user_set_mem_table_postcopy(dev, mem);
+    }
+
     VhostUserMsg msg = {
         .hdr.request = VHOST_USER_SET_MEM_TABLE,
         .hdr.flags = VHOST_USER_VERSION,
-- 
2.14.3