Commit b650d5f4 authored by Raphael Norwitz's avatar Raphael Norwitz Committed by Michael S. Tsirkin
Browse files

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: default avatarRaphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <1588533678-23450-11-git-send-email-raphael.norwitz@nutanix.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 875b9fd9

contrib/libvhost-user/libvhost-user.c

+9 −8
Original line number Diff line number Diff line
@@ -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;

}

contrib/libvhost-user/libvhost-user.h

+11 −4
Original line number Diff line number Diff line
@@ -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;