CC'ing MarcAndre and Michael S Tsirkin.
On Fri, Jun 24, 2016 at 1:47 PM, Prerna Saxena <saxenap....@gmail.com>
wrote:
> From: Prerna Saxena <prerna.sax...@nutanix.com>
>
> Signed-off-by: Prerna Saxena <prerna.sax...@nutanix.com>
> ---
> docs/specs/vhost-user.txt | 36 +++++++++++
> hw/virtio/vhost-user.c | 153
> +++++++++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 186 insertions(+), 3 deletions(-)
>
> diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
> index 777c49c..e5388b2 100644
> --- a/docs/specs/vhost-user.txt
> +++ b/docs/specs/vhost-user.txt
> @@ -37,6 +37,7 @@ consists of 3 header fields and a payload:
> * Flags: 32-bit bit field:
> - Lower 2 bits are the version (currently 0x01)
> - Bit 2 is the reply flag - needs to be sent on each reply from the
> slave
> + - Bit 3 is the need_response flag - see
> VHOST_USER_PROTOCOL_F_REPLY_ACK for details.
> * Size - 32-bit size of the payload
>
>
> @@ -126,6 +127,8 @@ the ones that do:
> * VHOST_GET_VRING_BASE
> * VHOST_SET_LOG_BASE (if VHOST_USER_PROTOCOL_F_LOG_SHMFD)
>
> +[ Also see the section on REPLY_ACK protocol extension]
> +
> There are several messages that the master sends with file descriptors
> passed
> in the ancillary data:
>
> @@ -254,6 +257,7 @@ Protocol features
> #define VHOST_USER_PROTOCOL_F_MQ 0
> #define VHOST_USER_PROTOCOL_F_LOG_SHMFD 1
> #define VHOST_USER_PROTOCOL_F_RARP 2
> +#define VHOST_USER_PROTOCOL_F_REPLY_ACK 3
>
> Message types
> -------------
> @@ -464,3 +468,35 @@ Message types
> is present in VHOST_USER_GET_PROTOCOL_FEATURES.
> The first 6 bytes of the payload contain the mac address of the
> guest to
> allow the vhost user backend to construct and broadcast the fake
> RARP.
> +
> +VHOST_USER_PROTOCOL_F_REPLY_ACK:
> +--------------------------------
> +The original vhost-user specification only demands responses for certain
> +commands. This differs from the vhost protocol implementation where
> commands
> +are sent over an ioctl() call and block until the client has completed.
> Not
> +receiving a response for commands like VHOST_SET_MEM_TABLE makes the
> sender
> +unable to tell when the client has finished (re)mapping the GPA, or
> whether it
> +has failed altogether.
> +
> +With this protocol extension negotiated, the sender can set the newly
> +introduced "need_response" [Bit 3] flag to any command. This indicates
> that
> +the client MUST to respond with a Payload VhostUserMsg indicating success
> or
> +failure. The payload should be set to zero on success or non-zero on
> failure.
> +In other words, response must be in the following format :
> +------------------------------------
> +| request | flags | size | payload |
> +------------------------------------
> +
> + * Request: 32-bit type of the original request which is being responded
> to.
> + * Flags: 32-bit bit field: (VHOST_USER_VERSION | VHOST_USER_REPLY_MASK)
> + * Size: size of the payload ( see below)
> + * Payload : a u64 integer, where a non-zero value indicates a failure.
> +
> +Note that as per the original vhost-user protocol, the following four
> messages anyway
> +require distinct responses from the vhost-user client process :
> + * VHOST_GET_FEATURES
> + * VHOST_GET_PROTOCOL_FEATURES
> + * VHOST_GET_VRING_BASE
> + * VHOST_SET_LOG_BASE (if VHOST_USER_PROTOCOL_F_LOG_SHMFD)
> +For these message types, the presence of VHOST_USER_PROTOCOL_F_REPLY_ACK
> or
> +need_response bit being set brings no behaviourial change.
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index 495e09f..f01ebb4 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -31,6 +31,7 @@ enum VhostUserProtocolFeature {
> VHOST_USER_PROTOCOL_F_MQ = 0,
> VHOST_USER_PROTOCOL_F_LOG_SHMFD = 1,
> VHOST_USER_PROTOCOL_F_RARP = 2,
> + VHOST_USER_PROTOCOL_F_REPLY_ACK = 3,
>
> VHOST_USER_PROTOCOL_F_MAX
> };
> @@ -82,8 +83,9 @@ typedef struct VhostUserLog {
> typedef struct VhostUserMsg {
> VhostUserRequest request;
>
> -#define VHOST_USER_VERSION_MASK (0x3)
> -#define VHOST_USER_REPLY_MASK (0x1<<2)
> +#define VHOST_USER_VERSION_MASK (0x3)
> +#define VHOST_USER_REPLY_MASK (0x1 << 2)
> +#define VHOST_USER_NEED_RESPONSE_MASK (0x1 << 3)
> uint32_t flags;
> uint32_t size; /* the following payload size */
> union {
> @@ -239,10 +241,17 @@ static int vhost_user_set_mem_table(struct vhost_dev
> *dev,
> 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);
> VhostUserMsg msg = {
> .request = VHOST_USER_SET_MEM_TABLE,
> .flags = VHOST_USER_VERSION,
> };
> + VhostUserRequest request = msg.request;
> +
> + if (reply_supported) {
> + msg.flags |= VHOST_USER_NEED_RESPONSE_MASK;
> + }
>
> for (i = 0; i < dev->mem->nregions; ++i) {
> struct vhost_memory_region *reg = dev->mem->regions + i;
> @@ -277,6 +286,20 @@ static int vhost_user_set_mem_table(struct vhost_dev
> *dev,
>
> vhost_user_write(dev, &msg, fds, fd_num);
>
> + if (reply_supported) {
> + if (vhost_user_read(dev, &msg) < 0) {
> + return 0;
> + }
> +
> + if (msg.request != request) {
> + error_report("Received unexpected msg type."
> + "Expected %d received %d",
> + request, msg.request);
> + return -1;
> + }
> + return msg.payload.u64 ? -1 : 0;
> + }
> +
> return 0;
> }
>
> @@ -289,9 +312,29 @@ static int vhost_user_set_vring_addr(struct vhost_dev
> *dev,
> .payload.addr = *addr,
> .size = sizeof(msg.payload.addr),
> };
> + VhostUserRequest request = msg.request;
> +
> + bool reply_supported = virtio_has_feature(dev->protocol_features,
> + VHOST_USER_PROTOCOL_F_REPLY_ACK);
>
> + if (reply_supported) {
> + msg.flags |= VHOST_USER_NEED_RESPONSE_MASK;
> + }
> vhost_user_write(dev, &msg, NULL, 0);
>
> + if (reply_supported) {
> + if (vhost_user_read(dev, &msg) < 0) {
> + return 0;
> + }
> +
> + if (msg.request != request) {
> + error_report("Received unexpected msg type."
> + "Expected %d received %d",
> + request, msg.request);
> + return -1;
> + }
> + return msg.payload.u64 ? -1 : 0;
> + }
> return 0;
> }
>
> @@ -313,8 +356,28 @@ static int vhost_set_vring(struct vhost_dev *dev,
> .size = sizeof(msg.payload.state),
> };
>
> + bool reply_supported = virtio_has_feature(dev->protocol_features,
> + VHOST_USER_PROTOCOL_F_REPLY_ACK);
> +
> + if (reply_supported) {
> + msg.flags |= VHOST_USER_NEED_RESPONSE_MASK;
> + }
> +
> vhost_user_write(dev, &msg, NULL, 0);
>
> + if (reply_supported) {
> + if (vhost_user_read(dev, &msg) < 0) {
> + return 0;
> + }
> +
> + if (msg.request != request) {
> + error_report("Received unexpected msg type."
> + "Expected %lu received %lu",
> + request, msg.request);
> + return -1;
> + }
> + return msg.payload.u64 ? -1 : 0;
> + }
> return 0;
> }
>
> @@ -395,6 +458,13 @@ static int vhost_set_vring_file(struct vhost_dev *dev,
> .size = sizeof(msg.payload.u64),
> };
>
> + bool reply_Supported = virtio_has_feature(dev->protocol_features,
> + VHOST_USER_PROTOCOL_F_REPLY_ACK);
> +
> + if (reply_supported) {
> + msg.flags |= VHOST_USER_NEED_RESPONSE_MASK;
> + }
> +
> if (ioeventfd_enabled() && file->fd > 0) {
> fds[fd_num++] = file->fd;
> } else {
> @@ -403,6 +473,20 @@ static int vhost_set_vring_file(struct vhost_dev *dev,
>
> vhost_user_write(dev, &msg, fds, fd_num);
>
> + if (reply_supported) {
> + if (vhost_user_read(dev, &msg) < 0) {
> + return 0;
> + }
> +
> + if (msg.request != request) {
> + error_report("Received unexpected msg type."
> + "Expected %d received %d",
> + request, msg.request);
> + return -1;
> + }
> + return msg.payload.u64 ? -1 : 0;
> + }
> +
> return 0;
> }
>
> @@ -489,8 +573,30 @@ static int vhost_user_set_owner(struct vhost_dev *dev)
> .flags = VHOST_USER_VERSION,
> };
>
> + VhostUserRequest request = msg.request;
> +
> + bool reply_supported = virtio_has_feature(dev->protocol_features,
> + VHOST_USER_PROTOCOL_F_REPLY_ACK);
> +
> + if (reply_supported) {
> + msg.flags |= VHOST_USER_NEED_RESPONSE_MASK;
> + }
> +
> vhost_user_write(dev, &msg, NULL, 0);
>
> + if (reply_supported) {
> + if (vhost_user_read(dev, &msg) < 0) {
> + return 0;
> + }
> +
> + if (msg.request != request) {
> + error_report("Received unexpected msg type."
> + "Expected %d received %d",
> + request, msg.request);
> + return -1;
> + }
> + return msg.payload.u64 ? -1 : 0;
> + }
> return 0;
> }
>
> @@ -500,9 +606,30 @@ static int vhost_user_reset_device(struct vhost_dev
> *dev)
> .request = VHOST_USER_RESET_OWNER,
> .flags = VHOST_USER_VERSION,
> };
> + VhostUserRequest request = msg.request;
> +
> + bool reply_supported = virtio_has_feature(dev->protocol_features,
> + VHOST_USER_PROTOCOL_F_REPLY_ACK);
> +
> + if (reply_supported) {
> + msg.flags |= VHOST_USER_NEED_RESPONSE_MASK;
> + }
>
> vhost_user_write(dev, &msg, NULL, 0);
>
> + if (reply_suported) {
> + if (vhost_user_read(dev, &msg) < 0) {
> + return 0;
> + }
> +
> + if (msg.request != request) {
> + error_report("Received unexpected msg type."
> + "Expected %d received %d",
> + request, msg.request);
> + return -1;
> + }
> + return msg.payload.u64 ? -1 : 0;
> + }
> return 0;
> }
>
> @@ -589,9 +716,15 @@ static int vhost_user_migration_done(struct vhost_dev
> *dev, char* mac_addr)
> {
> VhostUserMsg msg = { 0 };
> int err;
> + VhostUserRequest request = msg.request;
> + bool reply_supported = virtio_has_feature(dev->protocol_features,
> + VHOST_USER_PROTOCOL_F_REPLY_ACK);
>
> assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
>
> + if (reply_supported) {
> + msg.flags |= VHOST_USER_NEED_RESPONSE_MASK;
> + }
> /* If guest supports GUEST_ANNOUNCE do nothing */
> if (virtio_has_feature(dev->acked_features,
> VIRTIO_NET_F_GUEST_ANNOUNCE)) {
> return 0;
> @@ -606,7 +739,21 @@ static int vhost_user_migration_done(struct vhost_dev
> *dev, char* mac_addr)
> msg.size = sizeof(msg.payload.u64);
>
> err = vhost_user_write(dev, &msg, NULL, 0);
> - return err;
> + if (reply_supported) {
> + if (vhost_user_read(dev, &msg) < 0) {
> + return 0;
> + }
> +
> + if (msg.request != request) {
> + error_report("Received unexpected msg type."
> + "Expected %d received %d",
> + request, msg.request);
> + return -1;
> + }
> + return msg.payload.u64 ? -1 : 0;
> + } else {
> + return err;
> + }
> }
> return -1;
> }
> --
> 1.8.1.2
>
>
