From 03c5ff306ec5657a91c17cee12ff710025921190 Mon Sep 17 00:00:00 2001 From: Maxime Coquelin Date: Tue, 6 Jun 2017 12:05:24 +0200 Subject: [PATCH 13/17] spec/vhost-user spec: Add IOMMU support RH-Author: Maxime Coquelin 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 RH-Acked-by: Xiao Wang RH-Acked-by: Jens Freimann 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 Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin (cherry picked from commit 6dcdd06e3b0d0c5651219013ec975348e2050041) Signed-off-by: Maxime Coquelin Signed-off-by: Miroslav Rezanina --- 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