| Message ID | 20170526142858.19931-7-maxime.coquelin@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, May 26, 2017 at 04:28:58PM +0200, Maxime Coquelin wrote: > 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> > --- > > v2: > - spec: fixed possible permission field values > - spec: rewrote "IOMMU support" section > docs/specs/vhost-user.txt | 86 +++++++++++++++++++++++++++++++++++++++++++++++ > hw/virtio/vhost-user.c | 31 +++++++++++++++++ > 2 files changed, 117 insertions(+) > > diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt > index 5fa7016..0799ef1 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 +273,40 @@ 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 generally 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. The exception is the rings information addresses > +shared with the VHOST_USER_SET_VRING_ADDR request, for which the master must > +send corresponding IOTLB updates before the rings are enabled. > + Is the implication that invalidates do not affect ring translations true? I find this problematic. If not then can we replace above with "may send"? > Slave communication > ------------------- > > @@ -514,6 +568,38 @@ 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 ea988fe..170fa68 100644 > --- a/hw/virtio/vhost-user.c > +++ b/hw/virtio/vhost-user.c > @@ -62,11 +62,13 @@ 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; > > @@ -104,6 +106,7 @@ typedef struct VhostUserMsg { > struct vhost_vring_addr addr; > VhostUserMemory memory; > VhostUserLog log; > + struct vhost_iotlb_msg iotlb; > } payload; > } QEMU_PACKED VhostUserMsg; > > @@ -615,6 +618,9 @@ 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; > @@ -862,6 +868,29 @@ 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, > @@ -886,4 +915,6 @@ 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, > }; > -- > 2.9.4
diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt index 5fa7016..0799ef1 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 +273,40 @@ 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 generally 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. The exception is the rings information addresses +shared with the VHOST_USER_SET_VRING_ADDR request, for which the master must +send corresponding IOTLB updates before the rings are enabled. + Slave communication ------------------- @@ -514,6 +568,38 @@ 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 ea988fe..170fa68 100644 --- a/hw/virtio/vhost-user.c +++ b/hw/virtio/vhost-user.c @@ -62,11 +62,13 @@ 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; @@ -104,6 +106,7 @@ typedef struct VhostUserMsg { struct vhost_vring_addr addr; VhostUserMemory memory; VhostUserLog log; + struct vhost_iotlb_msg iotlb; } payload; } QEMU_PACKED VhostUserMsg; @@ -615,6 +618,9 @@ 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; @@ -862,6 +868,29 @@ 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, @@ -886,4 +915,6 @@ 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, };
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> --- v2: - spec: fixed possible permission field values - spec: rewrote "IOMMU support" section docs/specs/vhost-user.txt | 86 +++++++++++++++++++++++++++++++++++++++++++++++ hw/virtio/vhost-user.c | 31 +++++++++++++++++ 2 files changed, 117 insertions(+)