Lift max ram slots limit in libvhost-user

Historically, VMs with vhost-user devices could hot-add memory a maximum
of 8 times. Now that the VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS
protocol feature has been added, VMs with vhost-user backends which
support this new feature can support a configurable number of ram slots
up to the maximum supported by the target platform.

This change adds VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS support for
backends built with libvhost-user, and increases the number of supported
ram slots from 8 to 32.

Memory hot-add, hot-remove and postcopy migration were tested with
the vhost-user-bridge sample.

Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <1588533678-23450-11-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 05:00:59 +00:00 committed by Michael S. Tsirkin
parent 875b9fd97b
commit b650d5f4b1
2 changed files with 20 additions and 12 deletions

View File

@ -269,7 +269,7 @@ have_userfault(void)
static bool
vu_message_read(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
{
char control[CMSG_SPACE(VHOST_MEMORY_MAX_NREGIONS * sizeof(int))] = { };
char control[CMSG_SPACE(VHOST_MEMORY_BASELINE_NREGIONS * sizeof(int))] = {};
struct iovec iov = {
.iov_base = (char *)vmsg,
.iov_len = VHOST_USER_HDR_SIZE,
@ -340,7 +340,7 @@ vu_message_write(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
{
int rc;
uint8_t *p = (uint8_t *)vmsg;
char control[CMSG_SPACE(VHOST_MEMORY_MAX_NREGIONS * sizeof(int))] = { };
char control[CMSG_SPACE(VHOST_MEMORY_BASELINE_NREGIONS * sizeof(int))] = {};
struct iovec iov = {
.iov_base = (char *)vmsg,
.iov_len = VHOST_USER_HDR_SIZE,
@ -353,7 +353,7 @@ vu_message_write(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
struct cmsghdr *cmsg;
memset(control, 0, sizeof(control));
assert(vmsg->fd_num <= VHOST_MEMORY_MAX_NREGIONS);
assert(vmsg->fd_num <= VHOST_MEMORY_BASELINE_NREGIONS);
if (vmsg->fd_num > 0) {
size_t fdsize = vmsg->fd_num * sizeof(int);
msg.msg_controllen = CMSG_SPACE(fdsize);
@ -780,7 +780,7 @@ static bool
vu_rem_mem_reg(VuDev *dev, VhostUserMsg *vmsg) {
int i, j;
bool found = false;
VuDevRegion shadow_regions[VHOST_MEMORY_MAX_NREGIONS] = {};
VuDevRegion shadow_regions[VHOST_USER_MAX_RAM_SLOTS] = {};
VhostUserMemoryRegion m = vmsg->payload.memreg.region, *msg_region = &m;
DPRINT("Removing region:\n");
@ -813,7 +813,7 @@ vu_rem_mem_reg(VuDev *dev, VhostUserMsg *vmsg) {
if (found) {
memcpy(dev->regions, shadow_regions,
sizeof(VuDevRegion) * VHOST_MEMORY_MAX_NREGIONS);
sizeof(VuDevRegion) * VHOST_USER_MAX_RAM_SLOTS);
DPRINT("Successfully removed a region\n");
dev->nregions--;
vmsg_set_reply_u64(vmsg, 0);
@ -1394,7 +1394,8 @@ vu_get_protocol_features_exec(VuDev *dev, VhostUserMsg *vmsg)
1ULL << VHOST_USER_PROTOCOL_F_SLAVE_REQ |
1ULL << VHOST_USER_PROTOCOL_F_HOST_NOTIFIER |
1ULL << VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD |
1ULL << VHOST_USER_PROTOCOL_F_REPLY_ACK;
1ULL << VHOST_USER_PROTOCOL_F_REPLY_ACK |
1ULL << VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS;
if (have_userfault()) {
features |= 1ULL << VHOST_USER_PROTOCOL_F_PAGEFAULT;
@ -1732,14 +1733,14 @@ static bool vu_handle_get_max_memslots(VuDev *dev, VhostUserMsg *vmsg)
{
vmsg->flags = VHOST_USER_REPLY_MASK | VHOST_USER_VERSION;
vmsg->size = sizeof(vmsg->payload.u64);
vmsg->payload.u64 = VHOST_MEMORY_MAX_NREGIONS;
vmsg->payload.u64 = VHOST_USER_MAX_RAM_SLOTS;
vmsg->fd_num = 0;
if (!vu_message_write(dev, dev->sock, vmsg)) {
vu_panic(dev, "Failed to send max ram slots: %s\n", strerror(errno));
}
DPRINT("u64: 0x%016"PRIx64"\n", (uint64_t) VHOST_MEMORY_MAX_NREGIONS);
DPRINT("u64: 0x%016"PRIx64"\n", (uint64_t) VHOST_USER_MAX_RAM_SLOTS);
return false;
}

View File

@ -28,7 +28,13 @@
#define VIRTQUEUE_MAX_SIZE 1024
#define VHOST_MEMORY_MAX_NREGIONS 8
#define VHOST_MEMORY_BASELINE_NREGIONS 8
/*
* Set a reasonable maximum number of ram slots, which will be supported by
* any architecture.
*/
#define VHOST_USER_MAX_RAM_SLOTS 32
typedef enum VhostSetConfigType {
VHOST_SET_CONFIG_TYPE_MASTER = 0,
@ -55,6 +61,7 @@ enum VhostUserProtocolFeature {
VHOST_USER_PROTOCOL_F_HOST_NOTIFIER = 11,
VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD = 12,
VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS = 14,
VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS = 15,
VHOST_USER_PROTOCOL_F_MAX
};
@ -123,7 +130,7 @@ typedef struct VhostUserMemoryRegion {
typedef struct VhostUserMemory {
uint32_t nregions;
uint32_t padding;
VhostUserMemoryRegion regions[VHOST_MEMORY_MAX_NREGIONS];
VhostUserMemoryRegion regions[VHOST_MEMORY_BASELINE_NREGIONS];
} VhostUserMemory;
typedef struct VhostUserMemRegMsg {
@ -190,7 +197,7 @@ typedef struct VhostUserMsg {
VhostUserInflight inflight;
} payload;
int fds[VHOST_MEMORY_MAX_NREGIONS];
int fds[VHOST_MEMORY_BASELINE_NREGIONS];
int fd_num;
uint8_t *data;
} VU_PACKED VhostUserMsg;
@ -368,7 +375,7 @@ typedef struct VuDevInflightInfo {
struct VuDev {
int sock;
uint32_t nregions;
VuDevRegion regions[VHOST_MEMORY_MAX_NREGIONS];
VuDevRegion regions[VHOST_USER_MAX_RAM_SLOTS];
VuVirtq *vq;
VuDevInflightInfo inflight_info;
int log_call_fd;