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Support adding individual regions in libvhost-user

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When the VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS is enabled, qemu will
transmit memory regions to a backend individually using the new message
VHOST_USER_ADD_MEM_REG. With this change vhost-user backends built with
libvhost-user can now map in new memory regions when VHOST_USER_ADD_MEM_REG
messages are received.

Qemu only sends VHOST_USER_ADD_MEM_REG messages when the
VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS feature is negotiated, and
since it is not yet supported in libvhost-user, this new functionality
is not yet used.

Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <1588533678-23450-9-git-send-email-raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Raphael Norwitz 2020-05-21 05:00:52 +00:00 committed by Michael S. Tsirkin
parent 6fb2e173d2
commit ec94c8e621
2 changed files with 110 additions and 0 deletions
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103
contrib/libvhost-user/libvhost-user.c
View file

@ -138,6 +138,7 @@ vu_request_to_string(unsigned int req)
REQ(VHOST_USER_GPU_SET_SOCKET),
REQ(VHOST_USER_VRING_KICK),
REQ(VHOST_USER_GET_MAX_MEM_SLOTS),
REQ(VHOST_USER_ADD_MEM_REG),
REQ(VHOST_USER_MAX),
};
#undef REQ
@ -662,6 +663,106 @@ generate_faults(VuDev *dev) {
return true;
}
static bool
vu_add_mem_reg(VuDev *dev, VhostUserMsg *vmsg) {
int i;
bool track_ramblocks = dev->postcopy_listening;
VhostUserMemoryRegion m = vmsg->payload.memreg.region, *msg_region = &m;
VuDevRegion *dev_region = &dev->regions[dev->nregions];
void *mmap_addr;
/*
* If we are in postcopy mode and we receive a u64 payload with a 0 value
* we know all the postcopy client bases have been recieved, and we
* should start generating faults.
*/
if (track_ramblocks &&
vmsg->size == sizeof(vmsg->payload.u64) &&
vmsg->payload.u64 == 0) {
(void)generate_faults(dev);
return false;
}
DPRINT("Adding region: %d\n", dev->nregions);
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.
*/
if (track_ramblocks) {
/*
* In postcopy we're using PROT_NONE here to catch anyone
* accessing it before we userfault.
*/
mmap_addr = mmap(0, dev_region->size + dev_region->mmap_offset,
PROT_NONE, MAP_SHARED,
vmsg->fds[0], 0);
} else {
mmap_addr = mmap(0, dev_region->size + dev_region->mmap_offset,
PROT_READ | PROT_WRITE, MAP_SHARED, vmsg->fds[0],
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[0]);
if (track_ramblocks) {
/*
* 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);
/* Send the message back to qemu with the addresses filled in. */
vmsg->fd_num = 0;
if (!vu_send_reply(dev, dev->sock, vmsg)) {
vu_panic(dev, "failed to respond to add-mem-region for postcopy");
return false;
}
DPRINT("Successfully added new region in postcopy\n");
dev->nregions++;
return false;
} else {
for (i = 0; i < dev->max_queues; i++) {
if (dev->vq[i].vring.desc) {
if (map_ring(dev, &dev->vq[i])) {
vu_panic(dev, "remapping queue %d for new memory region",
i);
}
}
}
DPRINT("Successfully added new region\n");
dev->nregions++;
vmsg_set_reply_u64(vmsg, 0);
return true;
}
}
static bool
vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
{
@ -1668,6 +1769,8 @@ vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
return vu_handle_vring_kick(dev, vmsg);
case VHOST_USER_GET_MAX_MEM_SLOTS:
return vu_handle_get_max_memslots(dev, vmsg);
case VHOST_USER_ADD_MEM_REG:
return vu_add_mem_reg(dev, vmsg);
default:
vmsg_close_fds(vmsg);
vu_panic(dev, "Unhandled request: %d", vmsg->request);

7
contrib/libvhost-user/libvhost-user.h
View file

@ -98,6 +98,7 @@ typedef enum VhostUserRequest {
VHOST_USER_GPU_SET_SOCKET = 33,
VHOST_USER_VRING_KICK = 35,
VHOST_USER_GET_MAX_MEM_SLOTS = 36,
VHOST_USER_ADD_MEM_REG = 37,
VHOST_USER_MAX
} VhostUserRequest;
@ -124,6 +125,11 @@ typedef struct VhostUserMemory {
VhostUserMemoryRegion regions[VHOST_MEMORY_MAX_NREGIONS];
} VhostUserMemory;
typedef struct VhostUserMemRegMsg {
uint32_t padding;
VhostUserMemoryRegion region;
} VhostUserMemRegMsg;
typedef struct VhostUserLog {
uint64_t mmap_size;
uint64_t mmap_offset;
@ -176,6 +182,7 @@ typedef struct VhostUserMsg {
struct vhost_vring_state state;
struct vhost_vring_addr addr;
VhostUserMemory memory;
VhostUserMemRegMsg memreg;
VhostUserLog log;
VhostUserConfig config;
VhostUserVringArea area;