All of lore.kernel.org
 help / color / mirror / Atom feed
From: Johannes Berg <johannes@sipsolutions.net>
To: linux-um@lists.infradead.org
Cc: Johannes Berg <johannes.berg@intel.com>
Subject: [PATCH 2/2] um: virtio: implement VHOST_USER_PROTOCOL_F_REPLY_ACK
Date: Wed,  4 Sep 2019 09:11:16 +0200	[thread overview]
Message-ID: <20190904071116.8204-2-johannes@sipsolutions.net> (raw)
In-Reply-To: <20190904071116.8204-1-johannes@sipsolutions.net>

From: Johannes Berg <johannes.berg@intel.com>

Implement the VHOST_USER_PROTOCOL_F_REPLY_ACK extension for both
slave requests (previous patch) where we have to reply and our
own requests where it helps understand if the slave failed.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 arch/um/drivers/vhost_user.h |  5 +-
 arch/um/drivers/virtio_uml.c | 97 +++++++++++++++++++++++++++++-------
 2 files changed, 84 insertions(+), 18 deletions(-)

diff --git a/arch/um/drivers/vhost_user.h b/arch/um/drivers/vhost_user.h
index 8aee9919581e..45ff5ea22fea 100644
--- a/arch/um/drivers/vhost_user.h
+++ b/arch/um/drivers/vhost_user.h
@@ -6,9 +6,11 @@
 
 /* Message flags */
 #define VHOST_USER_FLAG_REPLY		BIT(2)
+#define VHOST_USER_FLAG_NEED_REPLY	BIT(3)
 /* Feature bits */
 #define VHOST_USER_F_PROTOCOL_FEATURES	30
 /* Protocol feature bits */
+#define VHOST_USER_PROTOCOL_F_REPLY_ACK		3
 #define VHOST_USER_PROTOCOL_F_SLAVE_REQ		5
 #define VHOST_USER_PROTOCOL_F_CONFIG		9
 /* Vring state index masks */
@@ -20,7 +22,8 @@
 /* Supported transport features */
 #define VHOST_USER_SUPPORTED_F		BIT_ULL(VHOST_USER_F_PROTOCOL_FEATURES)
 /* Supported protocol features */
-#define VHOST_USER_SUPPORTED_PROTOCOL_F	(BIT_ULL(VHOST_USER_PROTOCOL_F_SLAVE_REQ) | \
+#define VHOST_USER_SUPPORTED_PROTOCOL_F	(BIT_ULL(VHOST_USER_PROTOCOL_F_REPLY_ACK) | \
+					 BIT_ULL(VHOST_USER_PROTOCOL_F_SLAVE_REQ) | \
 					 BIT_ULL(VHOST_USER_PROTOCOL_F_CONFIG))
 
 enum vhost_user_request {
diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c
index a261977244b9..09009c05488e 100644
--- a/arch/um/drivers/virtio_uml.c
+++ b/arch/um/drivers/virtio_uml.c
@@ -159,30 +159,64 @@ static int vhost_user_recv_req(struct virtio_uml_device *vu_dev,
 	if (rc)
 		return rc;
 
-	if (msg->header.flags != VHOST_USER_VERSION)
+	if ((msg->header.flags & ~VHOST_USER_FLAG_NEED_REPLY) !=
+			VHOST_USER_VERSION)
 		return -EPROTO;
 
 	return 0;
 }
 
 static int vhost_user_send(struct virtio_uml_device *vu_dev,
-			   struct vhost_user_msg *msg,
+			   bool need_response, struct vhost_user_msg *msg,
 			   int *fds, size_t num_fds)
 {
 	size_t size = sizeof(msg->header) + msg->header.size;
+	bool request_ack;
+	int rc;
 
 	msg->header.flags |= VHOST_USER_VERSION;
-	return full_sendmsg_fds(vu_dev->sock, msg, size, fds, num_fds);
+
+	/*
+	 * The need_response flag indicates that we already need a response,
+	 * e.g. to read the features. In these cases, don't request an ACK as
+	 * it is meaningless. Also request an ACK only if supported.
+	 */
+	request_ack = !need_response;
+	if (!(vu_dev->protocol_features &
+			BIT_ULL(VHOST_USER_PROTOCOL_F_REPLY_ACK)))
+		request_ack = false;
+
+	if (request_ack)
+		msg->header.flags |= VHOST_USER_FLAG_NEED_REPLY;
+
+	rc = full_sendmsg_fds(vu_dev->sock, msg, size, fds, num_fds);
+	if (rc < 0)
+		return rc;
+
+	if (request_ack) {
+		uint64_t status;
+
+		rc = vhost_user_recv_u64(vu_dev, &status);
+		if (rc)
+			return rc;
+
+		if (status) {
+			vu_err(vu_dev, "slave reports error: %llu\n", status);
+			return -EIO;
+		}
+	}
+
+	return 0;
 }
 
 static int vhost_user_send_no_payload(struct virtio_uml_device *vu_dev,
-				      u32 request)
+				      bool need_response, u32 request)
 {
 	struct vhost_user_msg msg = {
 		.header.request = request,
 	};
 
-	return vhost_user_send(vu_dev, &msg, NULL, 0);
+	return vhost_user_send(vu_dev, need_response, &msg, NULL, 0);
 }
 
 static int vhost_user_send_no_payload_fd(struct virtio_uml_device *vu_dev,
@@ -192,7 +226,7 @@ static int vhost_user_send_no_payload_fd(struct virtio_uml_device *vu_dev,
 		.header.request = request,
 	};
 
-	return vhost_user_send(vu_dev, &msg, &fd, 1);
+	return vhost_user_send(vu_dev, false, &msg, &fd, 1);
 }
 
 static int vhost_user_send_u64(struct virtio_uml_device *vu_dev,
@@ -204,18 +238,19 @@ static int vhost_user_send_u64(struct virtio_uml_device *vu_dev,
 		.payload.integer = value,
 	};
 
-	return vhost_user_send(vu_dev, &msg, NULL, 0);
+	return vhost_user_send(vu_dev, false, &msg, NULL, 0);
 }
 
 static int vhost_user_set_owner(struct virtio_uml_device *vu_dev)
 {
-	return vhost_user_send_no_payload(vu_dev, VHOST_USER_SET_OWNER);
+	return vhost_user_send_no_payload(vu_dev, false, VHOST_USER_SET_OWNER);
 }
 
 static int vhost_user_get_features(struct virtio_uml_device *vu_dev,
 				   u64 *features)
 {
-	int rc = vhost_user_send_no_payload(vu_dev, VHOST_USER_GET_FEATURES);
+	int rc = vhost_user_send_no_payload(vu_dev, true,
+					    VHOST_USER_GET_FEATURES);
 
 	if (rc)
 		return rc;
@@ -231,7 +266,7 @@ static int vhost_user_set_features(struct virtio_uml_device *vu_dev,
 static int vhost_user_get_protocol_features(struct virtio_uml_device *vu_dev,
 					    u64 *protocol_features)
 {
-	int rc = vhost_user_send_no_payload(vu_dev,
+	int rc = vhost_user_send_no_payload(vu_dev, true,
 			VHOST_USER_GET_PROTOCOL_FEATURES);
 
 	if (rc)
@@ -246,9 +281,32 @@ static int vhost_user_set_protocol_features(struct virtio_uml_device *vu_dev,
 				   protocol_features);
 }
 
+static void vhost_user_reply(struct virtio_uml_device *vu_dev,
+			     struct vhost_user_msg *msg, int response)
+{
+	struct vhost_user_msg reply = {
+		.payload.integer = response,
+	};
+	size_t size = sizeof(reply.header) + sizeof(reply.payload.integer);
+	int rc;
+
+	reply.header = msg->header;
+	reply.header.flags &= ~VHOST_USER_FLAG_NEED_REPLY;
+	reply.header.flags |= VHOST_USER_FLAG_REPLY;
+	reply.header.size = sizeof(reply.payload.integer);
+
+	rc = full_sendmsg_fds(vu_dev->req_fd, &reply, size, NULL, 0);
+
+	if (rc)
+		vu_err(vu_dev,
+		       "sending reply to slave request failed: %d (size %zu)\n",
+		       rc, size);
+}
+
 static irqreturn_t vu_req_interrupt(int irq, void *data)
 {
 	struct virtio_uml_device *vu_dev = data;
+	int response = 1;
 	struct {
 		struct vhost_user_msg msg;
 		u8 extra_payload[512];
@@ -265,6 +323,7 @@ static irqreturn_t vu_req_interrupt(int irq, void *data)
 	switch (msg.msg.header.request) {
 	case VHOST_USER_SLAVE_CONFIG_CHANGE_MSG:
 		virtio_config_changed(&vu_dev->vdev);
+		response = 0;
 		break;
 	case VHOST_USER_SLAVE_IOTLB_MSG:
 		/* not supported - VIRTIO_F_IOMMU_PLATFORM */
@@ -275,6 +334,9 @@ static irqreturn_t vu_req_interrupt(int irq, void *data)
 		       msg.msg.header.request);
 	}
 
+	if (msg.msg.header.flags & VHOST_USER_FLAG_NEED_REPLY)
+		vhost_user_reply(vu_dev, &msg.msg, response);
+
 	return IRQ_HANDLED;
 }
 
@@ -360,7 +422,7 @@ static void vhost_user_get_config(struct virtio_uml_device *vu_dev,
 	msg->payload.config.offset = 0;
 	msg->payload.config.size = cfg_size;
 
-	rc = vhost_user_send(vu_dev, msg, NULL, 0);
+	rc = vhost_user_send(vu_dev, true, msg, NULL, 0);
 	if (rc) {
 		vu_err(vu_dev, "sending VHOST_USER_GET_CONFIG failed: %d\n",
 		       rc);
@@ -411,7 +473,7 @@ static void vhost_user_set_config(struct virtio_uml_device *vu_dev,
 	msg->payload.config.size = len;
 	memcpy(msg->payload.config.payload, buf, len);
 
-	rc = vhost_user_send(vu_dev, msg, NULL, 0);
+	rc = vhost_user_send(vu_dev, false, msg, NULL, 0);
 	if (rc)
 		vu_err(vu_dev, "sending VHOST_USER_SET_CONFIG failed: %d\n",
 		       rc);
@@ -462,7 +524,8 @@ static int vhost_user_set_mem_table(struct virtio_uml_device *vu_dev)
 			return rc;
 	}
 
-	return vhost_user_send(vu_dev, &msg, fds, msg.payload.mem_regions.num);
+	return vhost_user_send(vu_dev, false, &msg, fds,
+			       msg.payload.mem_regions.num);
 }
 
 static int vhost_user_set_vring_state(struct virtio_uml_device *vu_dev,
@@ -475,7 +538,7 @@ static int vhost_user_set_vring_state(struct virtio_uml_device *vu_dev,
 		.payload.vring_state.num = num,
 	};
 
-	return vhost_user_send(vu_dev, &msg, NULL, 0);
+	return vhost_user_send(vu_dev, false, &msg, NULL, 0);
 }
 
 static int vhost_user_set_vring_num(struct virtio_uml_device *vu_dev,
@@ -506,7 +569,7 @@ static int vhost_user_set_vring_addr(struct virtio_uml_device *vu_dev,
 		.payload.vring_addr.log = log,
 	};
 
-	return vhost_user_send(vu_dev, &msg, NULL, 0);
+	return vhost_user_send(vu_dev, false, &msg, NULL, 0);
 }
 
 static int vhost_user_set_vring_fd(struct virtio_uml_device *vu_dev,
@@ -522,9 +585,9 @@ static int vhost_user_set_vring_fd(struct virtio_uml_device *vu_dev,
 		return -EINVAL;
 	if (fd < 0) {
 		msg.payload.integer |= VHOST_USER_VRING_POLL_MASK;
-		return vhost_user_send(vu_dev, &msg, NULL, 0);
+		return vhost_user_send(vu_dev, false, &msg, NULL, 0);
 	}
-	return vhost_user_send(vu_dev, &msg, &fd, 1);
+	return vhost_user_send(vu_dev, false, &msg, &fd, 1);
 }
 
 static int vhost_user_set_vring_call(struct virtio_uml_device *vu_dev,
-- 
2.20.1


_______________________________________________
linux-um mailing list
linux-um@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-um


  reply	other threads:[~2019-09-04  7:11 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-04  7:11 [PATCH 1/2] um: virtio: implement VHOST_USER_PROTOCOL_F_SLAVE_REQ Johannes Berg
2019-09-04  7:11 ` Johannes Berg [this message]
2019-09-04 13:00 ` Johannes Berg

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190904071116.8204-2-johannes@sipsolutions.net \
    --to=johannes@sipsolutions.net \
    --cc=johannes.berg@intel.com \
    --cc=linux-um@lists.infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.