From 03c5ff306ec5657a91c17cee12ff710025921190 Mon Sep 17 00:00:00 2001
From: Maxime Coquelin <maxime.coquelin@redhat.com>
Date: Tue, 6 Jun 2017 12:05:24 +0200
Subject: [PATCH 13/17] spec/vhost-user spec: Add IOMMU support
RH-Author: Maxime Coquelin <maxime.coquelin@redhat.com>
Message-id: <20170606120524.3050-6-maxime.coquelin@redhat.com>
Patchwork-id: 75498
O-Subject: [RHV-7.4 qemu-kvm-rhev PATCH 5/5] spec/vhost-user spec: Add IOMMU support
Bugzilla: 1451862
RH-Acked-by: Peter Xu <peterx@redhat.com>
RH-Acked-by: Xiao Wang <jasowang@redhat.com>
RH-Acked-by: Jens Freimann <jfreiman@redhat.com>
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 <maxime.coquelin@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 6dcdd06e3b0d0c5651219013ec975348e2050041)
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
docs/specs/vhost-user.txt | 84 +++++++++++++++++++++++++++++++++++++++++++++++
hw/net/vhost_net.c | 1 +
hw/virtio/vhost-user.c | 48 +++++++++++++++++++++++++--
3 files changed, 130 insertions(+), 3 deletions(-)
diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
index 5fa7016..481ab56 100644
--- a/docs/specs/vhost-user.txt
+++ b/docs/specs/vhost-user.txt
@@ -97,6 +97,25 @@ 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 I/O virtual address programmed by the guest
+ Size: a 64-bit size
+ User address: a 64-bit user address
+ Permissions: a 8-bit value:
+ - 0: No access
+ - 1: Read access
+ - 2: Write access
+ - 3: Read/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 +128,7 @@ typedef struct VhostUserMsg {
struct vhost_vring_addr addr;
VhostUserMemory memory;
VhostUserLog log;
+ struct vhost_iotlb_msg iotlb;
};
} QEMU_PACKED VhostUserMsg;
@@ -253,6 +273,38 @@ 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
+sends IOTLB entries update & invalidation by sending VHOST_USER_IOTLB_MSG
+requests to the slave with a struct vhost_iotlb_msg as 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. Addresses and size must be within vhost memory regions set
+via the VHOST_USER_SET_MEM_TABLE request. 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.
+
+The slave relies on the slave communcation channel (see "Slave communication"
+section below) to send IOTLB miss and access failure events, by sending
+VHOST_USER_SLAVE_IOTLB_MSG requests to the master with a struct vhost_iotlb_msg
+as 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. For miss events, completed
+operation means either master sent an update message containing the IOTLB entry
+containing requested address and permission, or master sent nothing if the IOTLB
+miss message is invalid (invalid IOVA or permission).
+
+The master isn't expected to take the initiative to send IOTLB update messages,
+as the slave sends IOTLB miss messages for the guest virtual memory areas it
+needs to access.
+
Slave communication
-------------------
@@ -514,6 +566,38 @@ 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/net/vhost_net.c b/hw/net/vhost_net.c
index 22874a9..e037db6 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -77,6 +77,7 @@ static const int user_feature_bits[] = {
VIRTIO_NET_F_HOST_UFO,
VIRTIO_NET_F_MRG_RXBUF,
VIRTIO_NET_F_MTU,
+ VIRTIO_F_IOMMU_PLATFORM,
/* This bit implies RARP isn't sent by QEMU out of band */
VIRTIO_NET_F_GUEST_ANNOUNCE,
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 0faf5df..c44bbad 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;
@@ -616,6 +619,9 @@ 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;
@@ -698,7 +704,7 @@ out:
static int vhost_user_init(struct vhost_dev *dev, void *opaque)
{
- uint64_t features;
+ uint64_t features, protocol_features;
struct vhost_user *u;
int err;
@@ -718,12 +724,13 @@ static int vhost_user_init(struct vhost_dev *dev, void *opaque)
dev->backend_features |= 1ULL << VHOST_USER_F_PROTOCOL_FEATURES;
err = vhost_user_get_u64(dev, VHOST_USER_GET_PROTOCOL_FEATURES,
- &features);
+ &protocol_features);
if (err < 0) {
return err;
}
- dev->protocol_features = features & VHOST_USER_PROTOCOL_FEATURE_MASK;
+ dev->protocol_features =
+ protocol_features & VHOST_USER_PROTOCOL_FEATURE_MASK;
err = vhost_user_set_protocol_features(dev, dev->protocol_features);
if (err < 0) {
return err;
@@ -737,6 +744,16 @@ static int vhost_user_init(struct vhost_dev *dev, void *opaque)
return err;
}
}
+
+ if (virtio_has_feature(features, VIRTIO_F_IOMMU_PLATFORM) &&
+ !(virtio_has_feature(dev->protocol_features,
+ VHOST_USER_PROTOCOL_F_SLAVE_REQ) &&
+ virtio_has_feature(dev->protocol_features,
+ VHOST_USER_PROTOCOL_F_REPLY_ACK))) {
+ error_report("IOMMU support requires reply-ack and "
+ "slave-req protocol features.");
+ return -1;
+ }
}
if (dev->migration_blocker == NULL &&
@@ -863,6 +880,29 @@ 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);
+}
+
+
+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,
@@ -887,4 +927,6 @@ 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,
};
--
1.8.3.1