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[Qemu-devel] [PATCH 6/6] spec/vhost-user spec: Add IOMMU support
From: |
Maxime Coquelin |
Subject: |
[Qemu-devel] [PATCH 6/6] spec/vhost-user spec: Add IOMMU support |
Date: |
Thu, 11 May 2017 14:32:46 +0200 |
This patch specifies and implements the master/slave communication
to support device IOTLB in slave.
The vhost_iotlb_msg structure introduced for kernel backends is
re-used, making the design close between the two backends.
An exception is the use of the secondary channel to enable the
slave to send IOTLB miss requests to the master.
Signed-off-by: Maxime Coquelin <address@hidden>
---
docs/specs/vhost-user.txt | 75 +++++++++++++++++++++++++++++++++++++++++++++++
hw/virtio/vhost-user.c | 31 ++++++++++++++++++++
2 files changed, 106 insertions(+)
diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
index 5fa7016..4a1f0c3 100644
--- a/docs/specs/vhost-user.txt
+++ b/docs/specs/vhost-user.txt
@@ -97,6 +97,23 @@ Depending on the request type, payload can be:
log offset: offset from start of supplied file descriptor
where logging starts (i.e. where guest address 0 would be logged)
+ * An IOTLB message
+ ---------------------------------------------------------
+ | iova | size | user address | permissions flags | type |
+ ---------------------------------------------------------
+
+ IOVA: a 64-bit guest I/O virtual address
+ Size: a 64-bit size
+ User address: a 64-bit user address
+ Permissions flags: a 8-bit bit field:
+ - Bit 0: Read access
+ - Bit 1: Write access
+ Type: a 8-bit IOTLB message type:
+ - 1: IOTLB miss
+ - 2: IOTLB update
+ - 3: IOTLB invalidate
+ - 4: IOTLB access fail
+
In QEMU the vhost-user message is implemented with the following struct:
typedef struct VhostUserMsg {
@@ -109,6 +126,7 @@ typedef struct VhostUserMsg {
struct vhost_vring_addr addr;
VhostUserMemory memory;
VhostUserLog log;
+ struct vhost_iotlb_msg iotlb;
};
} QEMU_PACKED VhostUserMsg;
@@ -253,6 +271,31 @@ Once the source has finished migration, rings will be
stopped by
the source. No further update must be done before rings are
restarted.
+IOMMU support
+-------------
+
+When the VIRTIO_F_IOMMU_PLATFORM feature has been negotiated, the master has
+to send IOTLB entries update & invalidation by sending VHOST_USER_IOTLB_MSG
+requests to the slave with a struct vhost_iotlb_msg payload. For update events,
+the iotlb payload has to be filled with the update message type (2), the I/O
+virtual address, the size, the user virtual address, and the permissions
+flags. For invalidation events, the iotlb payload has to be filled with the
+invalidation message type (3), the I/O virtual address and the size. On
+success, the slave is expected to reply with a zero payload, non-zero
+otherwise.
+
+When the VHOST_USER_PROTOCOL_F_SLAVE_REQ is supported by the slave, and the
+master initiated the slave to master communication channel using the
+VHOST_USER_SET_SLAVE_REQ_FD request, the slave can send IOTLB miss and access
+failure events by sending VHOST_USER_SLAVE_IOTLB_MSG requests to the master
+with a struct vhost_iotlb_msg payload. For miss events, the iotlb payload has
+to be filled with the miss message type (1), the I/O virtual address and the
+permissions flags. For access failure event, the iotlb payload has to be
+filled with the access failure message type (4), the I/O virtual address and
+the permissions flags. For synchronization purpose, the slave may rely on the
+reply-ack feature, so the master may send a reply when operation is completed
+if the reply-ack feature is negotiated and slaves requests a reply.
+
Slave communication
-------------------
@@ -514,6 +557,38 @@ Master message types
If VHOST_USER_PROTOCOL_F_REPLY_ACK is negotiated, slave must respond
with zero for success, non-zero otherwise.
+ * VHOST_USER_IOTLB_MSG
+
+ Id: 22
+ Equivalent ioctl: N/A (equivalent to VHOST_IOTLB_MSG message type)
+ Master payload: struct vhost_iotlb_msg
+ Slave payload: u64
+
+ Send IOTLB messages with struct vhost_iotlb_msg as payload.
+ Master sends such requests to update and invalidate entries in the device
+ IOTLB. The slave has to acknowledge the request with sending zero as u64
+ payload for success, non-zero otherwise.
+ This request should be send only when VIRTIO_F_IOMMU_PLATFORM feature
+ has been successfully negotiated.
+
+Slave message types
+-------------------
+
+ * VHOST_USER_SLAVE_IOTLB_MSG
+
+ Id: 1
+ Equivalent ioctl: N/A (equivalent to VHOST_IOTLB_MSG message type)
+ Slave payload: struct vhost_iotlb_msg
+ Master payload: N/A
+
+ Send IOTLB messages with struct vhost_iotlb_msg as payload.
+ Slave sends such requests to notify of an IOTLB miss, or an IOTLB
+ access failure. If VHOST_USER_PROTOCOL_F_REPLY_ACK is negotiated,
+ and slave set the VHOST_USER_NEED_REPLY flag, master must respond with
+ zero when operation is successfully completed, or non-zero otherwise.
+ This request should be send only when VIRTIO_F_IOMMU_PLATFORM feature
+ has been successfully negotiated.
+
VHOST_USER_PROTOCOL_F_REPLY_ACK:
-------------------------------
The original vhost-user specification only demands replies for certain
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index fbc09fa..2c93181 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -63,11 +63,13 @@ typedef enum VhostUserRequest {
VHOST_USER_SEND_RARP = 19,
VHOST_USER_NET_SET_MTU = 20,
VHOST_USER_SET_SLAVE_REQ_FD = 21,
+ VHOST_USER_IOTLB_MSG = 22,
VHOST_USER_MAX
} VhostUserRequest;
typedef enum VhostUserSlaveRequest {
VHOST_USER_SLAVE_NONE = 0,
+ VHOST_USER_SLAVE_IOTLB_MSG = 1,
VHOST_USER_SLAVE_MAX
} VhostUserSlaveRequest;
@@ -105,6 +107,7 @@ typedef struct VhostUserMsg {
struct vhost_vring_addr addr;
VhostUserMemory memory;
VhostUserLog log;
+ struct vhost_iotlb_msg iotlb;
} payload;
} QEMU_PACKED VhostUserMsg;
@@ -611,6 +614,9 @@ static void slave_read(void *opaque)
}
switch (msg.request) {
+ case VHOST_USER_SLAVE_IOTLB_MSG:
+ ret = vhost_backend_handle_iotlb_msg(dev, &msg.payload.iotlb);
+ break;
default:
error_report("Received unexpected msg type.");
ret = -EINVAL;
@@ -858,6 +864,29 @@ static int vhost_user_net_set_mtu(struct vhost_dev *dev,
uint16_t mtu)
return 0;
}
+static int vhost_user_send_device_iotlb_msg(struct vhost_dev *dev,
+ struct vhost_iotlb_msg *imsg)
+{
+ VhostUserMsg msg = {
+ .request = VHOST_USER_IOTLB_MSG,
+ .size = sizeof(msg.payload.iotlb),
+ .flags = VHOST_USER_VERSION | VHOST_USER_NEED_REPLY_MASK,
+ .payload.iotlb = *imsg,
+ };
+
+ if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
+ return -EFAULT;
+ }
+
+ return process_message_reply(dev, msg.request);
+}
+
+
+static void vhost_user_set_iotlb_callback(struct vhost_dev *dev, int enabled)
+{
+ /* No-op as the receive channel is not dedicated to IOTLB messages. */
+}
+
const VhostOps user_ops = {
.backend_type = VHOST_BACKEND_TYPE_USER,
.vhost_backend_init = vhost_user_init,
@@ -882,4 +911,6 @@ const VhostOps user_ops = {
.vhost_migration_done = vhost_user_migration_done,
.vhost_backend_can_merge = vhost_user_can_merge,
.vhost_net_set_mtu = vhost_user_net_set_mtu,
+ .vhost_set_iotlb_callback = vhost_user_set_iotlb_callback,
+ .vhost_send_device_iotlb_msg = vhost_user_send_device_iotlb_msg,
};
--
2.9.3
- [Qemu-devel] [PATCH 3/6] vhost: Update rings information for IOTLB earlier, (continued)
- [Qemu-devel] [PATCH 3/6] vhost: Update rings information for IOTLB earlier, Maxime Coquelin, 2017/05/11
- Re: [Qemu-devel] [PATCH 3/6] vhost: Update rings information for IOTLB earlier, Michael S. Tsirkin, 2017/05/11
- Re: [Qemu-devel] [PATCH 3/6] vhost: Update rings information for IOTLB earlier, Maxime Coquelin, 2017/05/12
- Re: [Qemu-devel] [PATCH 3/6] vhost: Update rings information for IOTLB earlier, Michael S. Tsirkin, 2017/05/17
- Re: [Qemu-devel] [PATCH 3/6] vhost: Update rings information for IOTLB earlier, Maxime Coquelin, 2017/05/18
- Re: [Qemu-devel] [PATCH 3/6] vhost: Update rings information for IOTLB earlier, Maxime Coquelin, 2017/05/18
- Re: [Qemu-devel] [PATCH 3/6] vhost: Update rings information for IOTLB earlier, Michael S. Tsirkin, 2017/05/18
[Qemu-devel] [PATCH 2/6] vhost: rework IOTLB messaging, Maxime Coquelin, 2017/05/11
[Qemu-devel] [PATCH 4/6] vhost-user: add vhost_user to hold the chr, Maxime Coquelin, 2017/05/11
[Qemu-devel] [PATCH 5/6] vhost-user: add slave-req-fd support, Maxime Coquelin, 2017/05/11
[Qemu-devel] [PATCH 6/6] spec/vhost-user spec: Add IOMMU support,
Maxime Coquelin <=
- Re: [Qemu-devel] [PATCH 6/6] spec/vhost-user spec: Add IOMMU support, Michael S. Tsirkin, 2017/05/11
- Re: [Qemu-devel] [PATCH 6/6] spec/vhost-user spec: Add IOMMU support, Maxime Coquelin, 2017/05/12
- Re: [Qemu-devel] [PATCH 6/6] spec/vhost-user spec: Add IOMMU support, Michael S. Tsirkin, 2017/05/12
- Re: [Qemu-devel] [PATCH 6/6] spec/vhost-user spec: Add IOMMU support, Jason Wang, 2017/05/15
- Re: [Qemu-devel] [PATCH 6/6] spec/vhost-user spec: Add IOMMU support, Michael S. Tsirkin, 2017/05/16
- Re: [Qemu-devel] [PATCH 6/6] spec/vhost-user spec: Add IOMMU support, Jason Wang, 2017/05/16
- Re: [Qemu-devel] [PATCH 6/6] spec/vhost-user spec: Add IOMMU support, Maxime Coquelin, 2017/05/17
- Re: [Qemu-devel] [PATCH 6/6] spec/vhost-user spec: Add IOMMU support, Jason Wang, 2017/05/19
- Re: [Qemu-devel] [PATCH 6/6] spec/vhost-user spec: Add IOMMU support, Maxime Coquelin, 2017/05/19
Re: [Qemu-devel] [PATCH 6/6] spec/vhost-user spec: Add IOMMU support, Maxime Coquelin, 2017/05/17