3 This driver produces EFI_RNG_PROTOCOL instances for virtio-rng devices.
5 The implementation is based on OvmfPkg/VirtioScsiDxe/VirtioScsi.c
7 Copyright (C) 2012, Red Hat, Inc.
8 Copyright (c) 2012 - 2014, Intel Corporation. All rights reserved.<BR>
12 Copyright (C) 2016, Linaro Ltd.
14 This program and the accompanying materials are licensed and made available
15 under the terms and conditions of the BSD License which accompanies this
16 distribution. The full text of the license may be found at
17 http://opensource.org/licenses/bsd-license.php
19 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
20 WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
24 #include <Library/BaseMemoryLib.h>
25 #include <Library/DebugLib.h>
26 #include <Library/MemoryAllocationLib.h>
27 #include <Library/UefiBootServicesTableLib.h>
28 #include <Library/UefiLib.h>
29 #include <Library/VirtioLib.h>
31 #include "VirtioRng.h"
34 Returns information about the random number generation implementation.
36 @param[in] This A pointer to the EFI_RNG_PROTOCOL
38 @param[in,out] RNGAlgorithmListSize On input, the size in bytes of
40 On output with a return code of
41 EFI_SUCCESS, the size in bytes of the
42 data returned in RNGAlgorithmList. On
43 output with a return code of
44 EFI_BUFFER_TOO_SMALL, the size of
45 RNGAlgorithmList required to obtain the
47 @param[out] RNGAlgorithmList A caller-allocated memory buffer filled
48 by the driver with one EFI_RNG_ALGORITHM
49 element for each supported RNG algorithm.
50 The list must not change across multiple
51 calls to the same driver. The first
52 algorithm in the list is the default
53 algorithm for the driver.
55 @retval EFI_SUCCESS The RNG algorithm list was returned
57 @retval EFI_UNSUPPORTED The services is not supported by this
59 @retval EFI_DEVICE_ERROR The list of algorithms could not be
60 retrieved due to a hardware or firmware
62 @retval EFI_INVALID_PARAMETER One or more of the parameters are
64 @retval EFI_BUFFER_TOO_SMALL The buffer RNGAlgorithmList is too small
72 IN EFI_RNG_PROTOCOL
*This
,
73 IN OUT UINTN
*RNGAlgorithmListSize
,
74 OUT EFI_RNG_ALGORITHM
*RNGAlgorithmList
77 if (This
== NULL
|| RNGAlgorithmListSize
== NULL
) {
78 return EFI_INVALID_PARAMETER
;
81 if (*RNGAlgorithmListSize
< sizeof (EFI_RNG_ALGORITHM
)) {
82 *RNGAlgorithmListSize
= sizeof (EFI_RNG_ALGORITHM
);
83 return EFI_BUFFER_TOO_SMALL
;
86 if (RNGAlgorithmList
== NULL
) {
87 return EFI_INVALID_PARAMETER
;
90 *RNGAlgorithmListSize
= sizeof (EFI_RNG_ALGORITHM
);
91 CopyGuid (RNGAlgorithmList
, &gEfiRngAlgorithmRaw
);
97 Produces and returns an RNG value using either the default or specified RNG
100 @param[in] This A pointer to the EFI_RNG_PROTOCOL
102 @param[in] RNGAlgorithm A pointer to the EFI_RNG_ALGORITHM that
103 identifies the RNG algorithm to use. May
104 be NULL in which case the function will
105 use its default RNG algorithm.
106 @param[in] RNGValueLength The length in bytes of the memory buffer
107 pointed to by RNGValue. The driver shall
108 return exactly this numbers of bytes.
109 @param[out] RNGValue A caller-allocated memory buffer filled
110 by the driver with the resulting RNG
113 @retval EFI_SUCCESS The RNG value was returned successfully.
114 @retval EFI_UNSUPPORTED The algorithm specified by RNGAlgorithm
115 is not supported by this driver.
116 @retval EFI_DEVICE_ERROR An RNG value could not be retrieved due
117 to a hardware or firmware error.
118 @retval EFI_NOT_READY There is not enough random data available
119 to satisfy the length requested by
121 @retval EFI_INVALID_PARAMETER RNGValue is NULL or RNGValueLength is
129 IN EFI_RNG_PROTOCOL
*This
,
130 IN EFI_RNG_ALGORITHM
*RNGAlgorithm
, OPTIONAL
131 IN UINTN RNGValueLength
,
136 DESC_INDICES Indices
;
137 volatile UINT8
*Buffer
;
143 if (This
== NULL
|| RNGValueLength
== 0 || RNGValue
== NULL
) {
144 return EFI_INVALID_PARAMETER
;
148 // We only support the raw algorithm, so reject requests for anything else
150 if (RNGAlgorithm
!= NULL
&&
151 !CompareGuid (RNGAlgorithm
, &gEfiRngAlgorithmRaw
)) {
152 return EFI_UNSUPPORTED
;
155 Buffer
= (volatile UINT8
*)AllocatePool (RNGValueLength
);
156 if (Buffer
== NULL
) {
157 return EFI_DEVICE_ERROR
;
160 Dev
= VIRTIO_ENTROPY_SOURCE_FROM_RNG (This
);
163 // The Virtio RNG device may return less data than we asked it to, and can
164 // only return MAX_UINT32 bytes per invocation. So loop as long as needed to
165 // get all the entropy we were asked for.
167 for (Index
= 0; Index
< RNGValueLength
; Index
+= Len
) {
168 BufferSize
= (UINT32
)MIN (RNGValueLength
- Index
, (UINTN
)MAX_UINT32
);
170 VirtioPrepare (&Dev
->Ring
, &Indices
);
171 VirtioAppendDesc (&Dev
->Ring
,
172 (UINTN
)Buffer
+ Index
,
177 if (VirtioFlush (Dev
->VirtIo
, 0, &Dev
->Ring
, &Indices
, &Len
) !=
179 Status
= EFI_DEVICE_ERROR
;
183 ASSERT (Len
<= BufferSize
);
186 for (Index
= 0; Index
< RNGValueLength
; Index
++) {
187 RNGValue
[Index
] = Buffer
[Index
];
189 Status
= EFI_SUCCESS
;
192 FreePool ((VOID
*)Buffer
);
200 IN OUT VIRTIO_RNG_DEV
*Dev
209 // Execute virtio-0.9.5, 2.2.1 Device Initialization Sequence.
211 NextDevStat
= 0; // step 1 -- reset device
212 Status
= Dev
->VirtIo
->SetDeviceStatus (Dev
->VirtIo
, NextDevStat
);
213 if (EFI_ERROR (Status
)) {
217 NextDevStat
|= VSTAT_ACK
; // step 2 -- acknowledge device presence
218 Status
= Dev
->VirtIo
->SetDeviceStatus (Dev
->VirtIo
, NextDevStat
);
219 if (EFI_ERROR (Status
)) {
223 NextDevStat
|= VSTAT_DRIVER
; // step 3 -- we know how to drive it
224 Status
= Dev
->VirtIo
->SetDeviceStatus (Dev
->VirtIo
, NextDevStat
);
225 if (EFI_ERROR (Status
)) {
230 // Set Page Size - MMIO VirtIo Specific
232 Status
= Dev
->VirtIo
->SetPageSize (Dev
->VirtIo
, EFI_PAGE_SIZE
);
233 if (EFI_ERROR (Status
)) {
238 // step 4a -- retrieve and validate features
240 Status
= Dev
->VirtIo
->GetDeviceFeatures (Dev
->VirtIo
, &Features
);
241 if (EFI_ERROR (Status
)) {
245 Features
&= VIRTIO_F_VERSION_1
;
248 // In virtio-1.0, feature negotiation is expected to complete before queue
249 // discovery, and the device can also reject the selected set of features.
251 if (Dev
->VirtIo
->Revision
>= VIRTIO_SPEC_REVISION (1, 0, 0)) {
252 Status
= Virtio10WriteFeatures (Dev
->VirtIo
, Features
, &NextDevStat
);
253 if (EFI_ERROR (Status
)) {
259 // step 4b -- allocate request virtqueue, just use #0
261 Status
= Dev
->VirtIo
->SetQueueSel (Dev
->VirtIo
, 0);
262 if (EFI_ERROR (Status
)) {
265 Status
= Dev
->VirtIo
->GetQueueNumMax (Dev
->VirtIo
, &QueueSize
);
266 if (EFI_ERROR (Status
)) {
271 // VirtioRngGetRNG() uses one descriptor
274 Status
= EFI_UNSUPPORTED
;
278 Status
= VirtioRingInit (QueueSize
, &Dev
->Ring
);
279 if (EFI_ERROR (Status
)) {
284 // Additional steps for MMIO: align the queue appropriately, and set the
285 // size. If anything fails from here on, we must release the ring resources.
287 Status
= Dev
->VirtIo
->SetQueueNum (Dev
->VirtIo
, QueueSize
);
288 if (EFI_ERROR (Status
)) {
292 Status
= Dev
->VirtIo
->SetQueueAlign (Dev
->VirtIo
, EFI_PAGE_SIZE
);
293 if (EFI_ERROR (Status
)) {
298 // step 4c -- Report GPFN (guest-physical frame number) of queue.
300 Status
= Dev
->VirtIo
->SetQueueAddress (Dev
->VirtIo
, &Dev
->Ring
);
301 if (EFI_ERROR (Status
)) {
306 // step 5 -- Report understood features and guest-tuneables.
308 if (Dev
->VirtIo
->Revision
< VIRTIO_SPEC_REVISION (1, 0, 0)) {
309 Features
&= ~(UINT64
)VIRTIO_F_VERSION_1
;
310 Status
= Dev
->VirtIo
->SetGuestFeatures (Dev
->VirtIo
, Features
);
311 if (EFI_ERROR (Status
)) {
317 // step 6 -- initialization complete
319 NextDevStat
|= VSTAT_DRIVER_OK
;
320 Status
= Dev
->VirtIo
->SetDeviceStatus (Dev
->VirtIo
, NextDevStat
);
321 if (EFI_ERROR (Status
)) {
326 // populate the exported interface's attributes
328 Dev
->Rng
.GetInfo
= VirtioRngGetInfo
;
329 Dev
->Rng
.GetRNG
= VirtioRngGetRNG
;
334 VirtioRingUninit (&Dev
->Ring
);
338 // Notify the host about our failure to setup: virtio-0.9.5, 2.2.2.1 Device
339 // Status. VirtIo access failure here should not mask the original error.
341 NextDevStat
|= VSTAT_FAILED
;
342 Dev
->VirtIo
->SetDeviceStatus (Dev
->VirtIo
, NextDevStat
);
344 return Status
; // reached only via Failed above
352 IN OUT VIRTIO_RNG_DEV
*Dev
356 // Reset the virtual device -- see virtio-0.9.5, 2.2.2.1 Device Status. When
357 // VIRTIO_CFG_WRITE() returns, the host will have learned to stay away from
358 // the old comms area.
360 Dev
->VirtIo
->SetDeviceStatus (Dev
->VirtIo
, 0);
361 VirtioRingUninit (&Dev
->Ring
);
365 // Event notification function enqueued by ExitBootServices().
379 // Reset the device. This causes the hypervisor to forget about the virtio
382 // We allocated said ring in EfiBootServicesData type memory, and code
383 // executing after ExitBootServices() is permitted to overwrite it.
386 Dev
->VirtIo
->SetDeviceStatus (Dev
->VirtIo
, 0);
391 // Probe, start and stop functions of this driver, called by the DXE core for
394 // The following specifications document these interfaces:
395 // - Driver Writer's Guide for UEFI 2.3.1 v1.01, 9 Driver Binding Protocol
396 // - UEFI Spec 2.3.1 + Errata C, 10.1 EFI Driver Binding Protocol
398 // The implementation follows:
399 // - Driver Writer's Guide for UEFI 2.3.1 v1.01
400 // - 5.1.3.4 OpenProtocol() and CloseProtocol()
401 // - UEFI Spec 2.3.1 + Errata C
402 // - 6.3 Protocol Handler Services
408 VirtioRngDriverBindingSupported (
409 IN EFI_DRIVER_BINDING_PROTOCOL
*This
,
410 IN EFI_HANDLE DeviceHandle
,
411 IN EFI_DEVICE_PATH_PROTOCOL
*RemainingDevicePath
415 VIRTIO_DEVICE_PROTOCOL
*VirtIo
;
418 // Attempt to open the device with the VirtIo set of interfaces. On success,
419 // the protocol is "instantiated" for the VirtIo device. Covers duplicate
420 // open attempts (EFI_ALREADY_STARTED).
422 Status
= gBS
->OpenProtocol (
423 DeviceHandle
, // candidate device
424 &gVirtioDeviceProtocolGuid
, // for generic VirtIo access
425 (VOID
**)&VirtIo
, // handle to instantiate
426 This
->DriverBindingHandle
, // requestor driver identity
427 DeviceHandle
, // ControllerHandle, according to
428 // the UEFI Driver Model
429 EFI_OPEN_PROTOCOL_BY_DRIVER
// get exclusive VirtIo access to
430 // the device; to be released
432 if (EFI_ERROR (Status
)) {
436 if (VirtIo
->SubSystemDeviceId
!= VIRTIO_SUBSYSTEM_ENTROPY_SOURCE
) {
437 Status
= EFI_UNSUPPORTED
;
441 // We needed VirtIo access only transitorily, to see whether we support the
444 gBS
->CloseProtocol (DeviceHandle
, &gVirtioDeviceProtocolGuid
,
445 This
->DriverBindingHandle
, DeviceHandle
);
452 VirtioRngDriverBindingStart (
453 IN EFI_DRIVER_BINDING_PROTOCOL
*This
,
454 IN EFI_HANDLE DeviceHandle
,
455 IN EFI_DEVICE_PATH_PROTOCOL
*RemainingDevicePath
461 Dev
= (VIRTIO_RNG_DEV
*) AllocateZeroPool (sizeof *Dev
);
463 return EFI_OUT_OF_RESOURCES
;
466 Status
= gBS
->OpenProtocol (DeviceHandle
, &gVirtioDeviceProtocolGuid
,
467 (VOID
**)&Dev
->VirtIo
, This
->DriverBindingHandle
,
468 DeviceHandle
, EFI_OPEN_PROTOCOL_BY_DRIVER
);
469 if (EFI_ERROR (Status
)) {
474 // VirtIo access granted, configure virtio-rng device.
476 Status
= VirtioRngInit (Dev
);
477 if (EFI_ERROR (Status
)) {
481 Status
= gBS
->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES
, TPL_CALLBACK
,
482 &VirtioRngExitBoot
, Dev
, &Dev
->ExitBoot
);
483 if (EFI_ERROR (Status
)) {
488 // Setup complete, attempt to export the driver instance's EFI_RNG_PROTOCOL
491 Dev
->Signature
= VIRTIO_RNG_SIG
;
492 Status
= gBS
->InstallProtocolInterface (&DeviceHandle
,
493 &gEfiRngProtocolGuid
, EFI_NATIVE_INTERFACE
,
495 if (EFI_ERROR (Status
)) {
502 gBS
->CloseEvent (Dev
->ExitBoot
);
505 VirtioRngUninit (Dev
);
508 gBS
->CloseProtocol (DeviceHandle
, &gVirtioDeviceProtocolGuid
,
509 This
->DriverBindingHandle
, DeviceHandle
);
521 VirtioRngDriverBindingStop (
522 IN EFI_DRIVER_BINDING_PROTOCOL
*This
,
523 IN EFI_HANDLE DeviceHandle
,
524 IN UINTN NumberOfChildren
,
525 IN EFI_HANDLE
*ChildHandleBuffer
529 EFI_RNG_PROTOCOL
*Rng
;
532 Status
= gBS
->OpenProtocol (
533 DeviceHandle
, // candidate device
534 &gEfiRngProtocolGuid
, // retrieve the RNG iface
535 (VOID
**)&Rng
, // target pointer
536 This
->DriverBindingHandle
, // requestor driver ident.
537 DeviceHandle
, // lookup req. for dev.
538 EFI_OPEN_PROTOCOL_GET_PROTOCOL
// lookup only, no new ref.
540 if (EFI_ERROR (Status
)) {
544 Dev
= VIRTIO_ENTROPY_SOURCE_FROM_RNG (Rng
);
547 // Handle Stop() requests for in-use driver instances gracefully.
549 Status
= gBS
->UninstallProtocolInterface (DeviceHandle
,
550 &gEfiRngProtocolGuid
, &Dev
->Rng
);
551 if (EFI_ERROR (Status
)) {
555 gBS
->CloseEvent (Dev
->ExitBoot
);
557 VirtioRngUninit (Dev
);
559 gBS
->CloseProtocol (DeviceHandle
, &gVirtioDeviceProtocolGuid
,
560 This
->DriverBindingHandle
, DeviceHandle
);
569 // The static object that groups the Supported() (ie. probe), Start() and
570 // Stop() functions of the driver together. Refer to UEFI Spec 2.3.1 + Errata
571 // C, 10.1 EFI Driver Binding Protocol.
573 STATIC EFI_DRIVER_BINDING_PROTOCOL gDriverBinding
= {
574 &VirtioRngDriverBindingSupported
,
575 &VirtioRngDriverBindingStart
,
576 &VirtioRngDriverBindingStop
,
577 0x10, // Version, must be in [0x10 .. 0xFFFFFFEF] for IHV-developed drivers
578 NULL
, // ImageHandle, to be overwritten by
579 // EfiLibInstallDriverBindingComponentName2() in VirtioRngEntryPoint()
580 NULL
// DriverBindingHandle, ditto
585 // The purpose of the following scaffolding (EFI_COMPONENT_NAME_PROTOCOL and
586 // EFI_COMPONENT_NAME2_PROTOCOL implementation) is to format the driver's name
587 // in English, for display on standard console devices. This is recommended for
588 // UEFI drivers that follow the UEFI Driver Model. Refer to the Driver Writer's
589 // Guide for UEFI 2.3.1 v1.01, 11 UEFI Driver and Controller Names.
593 EFI_UNICODE_STRING_TABLE mDriverNameTable
[] = {
594 { "eng;en", L
"Virtio Random Number Generator Driver" },
599 EFI_COMPONENT_NAME_PROTOCOL gComponentName
;
604 VirtioRngGetDriverName (
605 IN EFI_COMPONENT_NAME_PROTOCOL
*This
,
607 OUT CHAR16
**DriverName
610 return LookupUnicodeString2 (
612 This
->SupportedLanguages
,
615 (BOOLEAN
)(This
== &gComponentName
) // Iso639Language
622 VirtioRngGetDeviceName (
623 IN EFI_COMPONENT_NAME_PROTOCOL
*This
,
624 IN EFI_HANDLE DeviceHandle
,
625 IN EFI_HANDLE ChildHandle
,
627 OUT CHAR16
**ControllerName
630 return EFI_UNSUPPORTED
;
634 EFI_COMPONENT_NAME_PROTOCOL gComponentName
= {
635 &VirtioRngGetDriverName
,
636 &VirtioRngGetDeviceName
,
637 "eng" // SupportedLanguages, ISO 639-2 language codes
641 EFI_COMPONENT_NAME2_PROTOCOL gComponentName2
= {
642 (EFI_COMPONENT_NAME2_GET_DRIVER_NAME
) &VirtioRngGetDriverName
,
643 (EFI_COMPONENT_NAME2_GET_CONTROLLER_NAME
) &VirtioRngGetDeviceName
,
644 "en" // SupportedLanguages, RFC 4646 language codes
649 // Entry point of this driver.
653 VirtioRngEntryPoint (
654 IN EFI_HANDLE ImageHandle
,
655 IN EFI_SYSTEM_TABLE
*SystemTable
658 return EfiLibInstallDriverBindingComponentName2 (