3 Utility functions used by virtio device drivers.
5 Copyright (C) 2012-2016, Red Hat, Inc.
6 Portion of Copyright (C) 2013, ARM Ltd.
7 Copyright (C) 2017, AMD Inc, All rights reserved.<BR>
9 SPDX-License-Identifier: BSD-2-Clause-Patent
13 #include <Library/BaseLib.h>
14 #include <Library/BaseMemoryLib.h>
15 #include <Library/DebugLib.h>
16 #include <Library/UefiBootServicesTableLib.h>
18 #include <Library/VirtioLib.h>
23 Configure a virtio ring.
25 This function sets up internal storage (the guest-host communication area)
26 and lays out several "navigation" (ie. no-ownership) pointers to parts of
29 Relevant sections from the virtio-0.9.5 spec:
31 - 2.3 Virtqueue Configuration.
33 @param[in] VirtIo The virtio device which will use the ring.
35 @param[in] The number of descriptors to allocate for the
36 virtio ring, as requested by the host.
38 @param[out] Ring The virtio ring to set up.
40 @return Status codes propagated from
41 VirtIo->AllocateSharedPages().
43 @retval EFI_SUCCESS Allocation and setup successful. Ring->Base
44 (and nothing else) is responsible for
51 IN VIRTIO_DEVICE_PROTOCOL
*VirtIo
,
58 volatile UINT8
*RingPagesPtr
;
60 RingSize
= ALIGN_VALUE (
61 sizeof *Ring
->Desc
* QueueSize
+
62 sizeof *Ring
->Avail
.Flags
+
63 sizeof *Ring
->Avail
.Idx
+
64 sizeof *Ring
->Avail
.Ring
* QueueSize
+
65 sizeof *Ring
->Avail
.UsedEvent
,
68 RingSize
+= ALIGN_VALUE (
69 sizeof *Ring
->Used
.Flags
+
70 sizeof *Ring
->Used
.Idx
+
71 sizeof *Ring
->Used
.UsedElem
* QueueSize
+
72 sizeof *Ring
->Used
.AvailEvent
,
76 // Allocate a shared ring buffer
78 Ring
->NumPages
= EFI_SIZE_TO_PAGES (RingSize
);
79 Status
= VirtIo
->AllocateSharedPages (
84 if (EFI_ERROR (Status
)) {
87 SetMem (Ring
->Base
, RingSize
, 0x00);
88 RingPagesPtr
= Ring
->Base
;
90 Ring
->Desc
= (volatile VOID
*) RingPagesPtr
;
91 RingPagesPtr
+= sizeof *Ring
->Desc
* QueueSize
;
93 Ring
->Avail
.Flags
= (volatile VOID
*) RingPagesPtr
;
94 RingPagesPtr
+= sizeof *Ring
->Avail
.Flags
;
96 Ring
->Avail
.Idx
= (volatile VOID
*) RingPagesPtr
;
97 RingPagesPtr
+= sizeof *Ring
->Avail
.Idx
;
99 Ring
->Avail
.Ring
= (volatile VOID
*) RingPagesPtr
;
100 RingPagesPtr
+= sizeof *Ring
->Avail
.Ring
* QueueSize
;
102 Ring
->Avail
.UsedEvent
= (volatile VOID
*) RingPagesPtr
;
103 RingPagesPtr
+= sizeof *Ring
->Avail
.UsedEvent
;
105 RingPagesPtr
= (volatile UINT8
*) Ring
->Base
+
106 ALIGN_VALUE (RingPagesPtr
- (volatile UINT8
*) Ring
->Base
,
109 Ring
->Used
.Flags
= (volatile VOID
*) RingPagesPtr
;
110 RingPagesPtr
+= sizeof *Ring
->Used
.Flags
;
112 Ring
->Used
.Idx
= (volatile VOID
*) RingPagesPtr
;
113 RingPagesPtr
+= sizeof *Ring
->Used
.Idx
;
115 Ring
->Used
.UsedElem
= (volatile VOID
*) RingPagesPtr
;
116 RingPagesPtr
+= sizeof *Ring
->Used
.UsedElem
* QueueSize
;
118 Ring
->Used
.AvailEvent
= (volatile VOID
*) RingPagesPtr
;
119 RingPagesPtr
+= sizeof *Ring
->Used
.AvailEvent
;
121 Ring
->QueueSize
= QueueSize
;
128 Tear down the internal resources of a configured virtio ring.
130 The caller is responsible to stop the host from using this ring before
131 invoking this function: the VSTAT_DRIVER_OK bit must be clear in
134 @param[in] VirtIo The virtio device which was using the ring.
136 @param[out] Ring The virtio ring to clean up.
142 IN VIRTIO_DEVICE_PROTOCOL
*VirtIo
,
146 VirtIo
->FreeSharedPages (VirtIo
, Ring
->NumPages
, Ring
->Base
);
147 SetMem (Ring
, sizeof *Ring
, 0x00);
153 Turn off interrupt notifications from the host, and prepare for appending
154 multiple descriptors to the virtio ring.
156 The calling driver must be in VSTAT_DRIVER_OK state.
158 @param[in,out] Ring The virtio ring we intend to append descriptors to.
160 @param[out] Indices The DESC_INDICES structure to initialize.
167 OUT DESC_INDICES
*Indices
171 // Prepare for virtio-0.9.5, 2.4.2 Receiving Used Buffers From the Device.
172 // We're going to poll the answer, the host should not send an interrupt.
174 *Ring
->Avail
.Flags
= (UINT16
) VRING_AVAIL_F_NO_INTERRUPT
;
177 // Prepare for virtio-0.9.5, 2.4.1 Supplying Buffers to the Device.
179 // Since we support only one in-flight descriptor chain, we can always build
180 // that chain starting at entry #0 of the descriptor table.
182 Indices
->HeadDescIdx
= 0;
183 Indices
->NextDescIdx
= Indices
->HeadDescIdx
;
188 Append a contiguous buffer for transmission / reception via the virtio ring.
190 This function implements the following section from virtio-0.9.5:
191 - 2.4.1.1 Placing Buffers into the Descriptor Table
193 Free space is taken as granted, since the individual drivers support only
194 synchronous requests and host side status is processed in lock-step with
195 request submission. It is the calling driver's responsibility to verify the
196 ring size in advance.
198 The caller is responsible for initializing *Indices with VirtioPrepare()
201 @param[in,out] Ring The virtio ring to append the buffer to,
204 @param[in] BufferDeviceAddress (Bus master device) start address of the
205 transmit / receive buffer.
207 @param[in] BufferSize Number of bytes to transmit or receive.
209 @param[in] Flags A bitmask of VRING_DESC_F_* flags. The
210 caller computes this mask dependent on
211 further buffers to append and transfer
212 direction. VRING_DESC_F_INDIRECT is
213 unsupported. The VRING_DESC.Next field is
214 always set, but the host only interprets
215 it dependent on VRING_DESC_F_NEXT.
217 @param[in,out] Indices Indices->HeadDescIdx is not accessed.
218 On input, Indices->NextDescIdx identifies
219 the next descriptor to carry the buffer.
220 On output, Indices->NextDescIdx is
221 incremented by one, modulo 2^16.
228 IN UINT64 BufferDeviceAddress
,
229 IN UINT32 BufferSize
,
231 IN OUT DESC_INDICES
*Indices
234 volatile VRING_DESC
*Desc
;
236 Desc
= &Ring
->Desc
[Indices
->NextDescIdx
++ % Ring
->QueueSize
];
237 Desc
->Addr
= BufferDeviceAddress
;
238 Desc
->Len
= BufferSize
;
240 Desc
->Next
= Indices
->NextDescIdx
% Ring
->QueueSize
;
246 Notify the host about the descriptor chain just built, and wait until the
249 @param[in] VirtIo The target virtio device to notify.
251 @param[in] VirtQueueId Identifies the queue for the target device.
253 @param[in,out] Ring The virtio ring with descriptors to submit.
255 @param[in] Indices Indices->NextDescIdx is not accessed.
256 Indices->HeadDescIdx identifies the head descriptor
257 of the descriptor chain.
259 @param[out] UsedLen On success, the total number of bytes, consecutively
260 across the buffers linked by the descriptor chain,
261 that the host wrote. May be NULL if the caller
262 doesn't care, or can compute the same information
263 from device-specific request structures linked by the
266 @return Error code from VirtIo->SetQueueNotify() if it fails.
268 @retval EFI_SUCCESS Otherwise, the host processed all descriptors.
274 IN VIRTIO_DEVICE_PROTOCOL
*VirtIo
,
275 IN UINT16 VirtQueueId
,
277 IN DESC_INDICES
*Indices
,
278 OUT UINT32
*UsedLen OPTIONAL
284 UINTN PollPeriodUsecs
;
287 // virtio-0.9.5, 2.4.1.2 Updating the Available Ring
289 // It is not exactly clear from the wording of the virtio-0.9.5
290 // specification, but each entry in the Available Ring references only the
291 // head descriptor of any given descriptor chain.
293 NextAvailIdx
= *Ring
->Avail
.Idx
;
295 // (Due to our lock-step progress, this is where the host will produce the
296 // used element with the head descriptor's index in it.)
298 LastUsedIdx
= NextAvailIdx
;
299 Ring
->Avail
.Ring
[NextAvailIdx
++ % Ring
->QueueSize
] =
300 Indices
->HeadDescIdx
% Ring
->QueueSize
;
303 // virtio-0.9.5, 2.4.1.3 Updating the Index Field
306 *Ring
->Avail
.Idx
= NextAvailIdx
;
309 // virtio-0.9.5, 2.4.1.4 Notifying the Device -- gratuitous notifications are
313 Status
= VirtIo
->SetQueueNotify (VirtIo
, VirtQueueId
);
314 if (EFI_ERROR (Status
)) {
319 // virtio-0.9.5, 2.4.2 Receiving Used Buffers From the Device
320 // Wait until the host processes and acknowledges our descriptor chain. The
321 // condition we use for polling is greatly simplified and relies on the
322 // synchronous, lock-step progress.
324 // Keep slowing down until we reach a poll period of slightly above 1 ms.
328 while (*Ring
->Used
.Idx
!= NextAvailIdx
) {
329 gBS
->Stall (PollPeriodUsecs
); // calls AcpiTimerLib::MicroSecondDelay
331 if (PollPeriodUsecs
< 1024) {
332 PollPeriodUsecs
*= 2;
339 if (UsedLen
!= NULL
) {
340 volatile CONST VRING_USED_ELEM
*UsedElem
;
342 UsedElem
= &Ring
->Used
.UsedElem
[LastUsedIdx
% Ring
->QueueSize
];
343 ASSERT (UsedElem
->Id
== Indices
->HeadDescIdx
);
344 *UsedLen
= UsedElem
->Len
;
353 Report the feature bits to the VirtIo 1.0 device that the VirtIo 1.0 driver
356 In VirtIo 1.0, a device can reject a self-inconsistent feature bitmap through
357 the new VSTAT_FEATURES_OK status bit. (For example if the driver requests a
358 higher level feature but clears a prerequisite feature.) This function is a
359 small wrapper around VIRTIO_DEVICE_PROTOCOL.SetGuestFeatures() that also
360 verifies if the VirtIo 1.0 device accepts the feature bitmap.
362 @param[in] VirtIo Report feature bits to this device.
364 @param[in] Features The set of feature bits that the driver wishes
365 to report. The caller is responsible to perform
366 any masking before calling this function; the
367 value is directly written with
368 VIRTIO_DEVICE_PROTOCOL.SetGuestFeatures().
370 @param[in,out] DeviceStatus On input, the status byte most recently written
371 to the device's status register. On output (even
372 on error), DeviceStatus will be updated so that
373 it is suitable for further status bit
374 manipulation and writing to the device's status
377 @retval EFI_SUCCESS The device accepted the configuration in Features.
379 @return EFI_UNSUPPORTED The device rejected the configuration in Features.
381 @retval EFI_UNSUPPORTED VirtIo->Revision is smaller than 1.0.0.
383 @return Error codes from the SetGuestFeatures(),
384 SetDeviceStatus(), GetDeviceStatus() member
390 Virtio10WriteFeatures (
391 IN VIRTIO_DEVICE_PROTOCOL
*VirtIo
,
393 IN OUT UINT8
*DeviceStatus
398 if (VirtIo
->Revision
< VIRTIO_SPEC_REVISION (1, 0, 0)) {
399 return EFI_UNSUPPORTED
;
402 Status
= VirtIo
->SetGuestFeatures (VirtIo
, Features
);
403 if (EFI_ERROR (Status
)) {
407 *DeviceStatus
|= VSTAT_FEATURES_OK
;
408 Status
= VirtIo
->SetDeviceStatus (VirtIo
, *DeviceStatus
);
409 if (EFI_ERROR (Status
)) {
413 Status
= VirtIo
->GetDeviceStatus (VirtIo
, DeviceStatus
);
414 if (EFI_ERROR (Status
)) {
418 if ((*DeviceStatus
& VSTAT_FEATURES_OK
) == 0) {
419 Status
= EFI_UNSUPPORTED
;
426 Provides the virtio device address required to access system memory from a
429 The interface follows the same usage pattern as defined in UEFI spec 2.6
430 (Section 13.2 PCI Root Bridge I/O Protocol)
432 The VirtioMapAllBytesInSharedBuffer() is similar to VIRTIO_MAP_SHARED
433 with exception that NumberOfBytes is IN-only parameter. The function
434 maps all the bytes specified in NumberOfBytes param in one consecutive
437 @param[in] VirtIo The virtio device for which the mapping is
440 @param[in] Operation Indicates if the bus master is going to
441 read or write to system memory.
443 @param[in] HostAddress The system memory address to map to shared
446 @param[in] NumberOfBytes Number of bytes to map.
448 @param[out] DeviceAddress The resulting shared map address for the
449 bus master to access the hosts HostAddress.
451 @param[out] Mapping A resulting token to pass to
455 @retval EFI_SUCCESS The NumberOfBytes is succesfully mapped.
456 @retval EFI_UNSUPPORTED The HostAddress cannot be mapped as a
458 @retval EFI_INVALID_PARAMETER One or more parameters are invalid.
459 @retval EFI_OUT_OF_RESOURCES The request could not be completed due to
460 a lack of resources. This includes the case
461 when NumberOfBytes bytes cannot be mapped
462 in one consecutive range.
463 @retval EFI_DEVICE_ERROR The system hardware could not map the
468 VirtioMapAllBytesInSharedBuffer (
469 IN VIRTIO_DEVICE_PROTOCOL
*VirtIo
,
470 IN VIRTIO_MAP_OPERATION Operation
,
471 IN VOID
*HostAddress
,
472 IN UINTN NumberOfBytes
,
473 OUT EFI_PHYSICAL_ADDRESS
*DeviceAddress
,
480 EFI_PHYSICAL_ADDRESS PhysicalAddress
;
482 Size
= NumberOfBytes
;
483 Status
= VirtIo
->MapSharedBuffer (
491 if (EFI_ERROR (Status
)) {
495 if (Size
< NumberOfBytes
) {
500 *DeviceAddress
= PhysicalAddress
;
505 VirtIo
->UnmapSharedBuffer (VirtIo
, MapInfo
);
506 return EFI_OUT_OF_RESOURCES
;
511 Map the ring buffer so that it can be accessed equally by both guest
514 @param[in] VirtIo The virtio device instance.
516 @param[in] Ring The virtio ring to map.
518 @param[out] RingBaseShift A resulting translation offset, to be
519 passed to VirtIo->SetQueueAddress().
521 @param[out] Mapping A resulting token to pass to
522 VirtIo->UnmapSharedBuffer().
524 @return Status code from VirtIo->MapSharedBuffer()
529 IN VIRTIO_DEVICE_PROTOCOL
*VirtIo
,
531 OUT UINT64
*RingBaseShift
,
536 EFI_PHYSICAL_ADDRESS DeviceAddress
;
538 Status
= VirtioMapAllBytesInSharedBuffer (
540 VirtioOperationBusMasterCommonBuffer
,
542 EFI_PAGES_TO_SIZE (Ring
->NumPages
),
546 if (EFI_ERROR (Status
)) {
550 *RingBaseShift
= DeviceAddress
- (UINT64
)(UINTN
)Ring
->Base
;