OvmfPkg/VirtioGpuDxe: initialize and tear down VirtIo GPU device

This patch implements the steps listed in section "3.1.1 Driver
Requirements: Device Initialization" of the Virtio V1.0 Committee Spec 04.
The VirtIo GPU is brought up in VirtioGpuDriverBindingStart(), and down in
VirtioGpuDriverBindingStop().

We also add an ExitBootServices() callback that resets the device. This
ensures that the device model abandons any guest memory areas when we
transfer control to the guest OS.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Ref: https://tianocore.acgmultimedia.com/show_bug.cgi?id=66
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

OvmfPkg/VirtioGpuDxe/Commands.c

@@ -0,0 +1,214 @@
+/** @file
+
+  VirtIo GPU initialization, and commands (primitives) for the GPU device.
+
+  Copyright (C) 2016, Red Hat, Inc.
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution. The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include <IndustryStandard/VirtioGpu.h>
+#include <Library/VirtioLib.h>
+
+#include "VirtioGpu.h"
+
+/**
+  Configure the VirtIo GPU device that underlies VgpuDev.
+
+  @param[in,out] VgpuDev  The VGPU_DEV object to set up VirtIo messaging for.
+                          On input, the caller is responsible for having
+                          initialized VgpuDev->VirtIo. On output, VgpuDev->Ring
+                          has been initialized, and synchronous VirtIo GPU
+                          commands (primitives) can be submitted to the device.
+
+  @retval EFI_SUCCESS      VirtIo GPU configuration successful.
+
+  @retval EFI_UNSUPPORTED  The host-side configuration of the VirtIo GPU is not
+                           supported by this driver.
+
+  @retval                  Error codes from underlying functions.
+**/
+EFI_STATUS
+VirtioGpuInit (
+  IN OUT VGPU_DEV *VgpuDev
+  )
+{
+  UINT8      NextDevStat;
+  EFI_STATUS Status;
+  UINT64     Features;
+  UINT16     QueueSize;
+
+  //
+  // Execute virtio-v1.0-cs04, 3.1.1 Driver Requirements: Device
+  // Initialization.
+  //
+  // 1. Reset the device.
+  //
+  NextDevStat = 0;
+  Status = VgpuDev->VirtIo->SetDeviceStatus (VgpuDev->VirtIo, NextDevStat);
+  if (EFI_ERROR (Status)) {
+    goto Failed;
+  }
+
+  //
+  // 2. Set the ACKNOWLEDGE status bit [...]
+  //
+  NextDevStat |= VSTAT_ACK;
+  Status = VgpuDev->VirtIo->SetDeviceStatus (VgpuDev->VirtIo, NextDevStat);
+  if (EFI_ERROR (Status)) {
+    goto Failed;
+  }
+
+  //
+  // 3. Set the DRIVER status bit [...]
+  //
+  NextDevStat |= VSTAT_DRIVER;
+  Status = VgpuDev->VirtIo->SetDeviceStatus (VgpuDev->VirtIo, NextDevStat);
+  if (EFI_ERROR (Status)) {
+    goto Failed;
+  }
+
+  //
+  // 4. Read device feature bits...
+  //
+  Status = VgpuDev->VirtIo->GetDeviceFeatures (VgpuDev->VirtIo, &Features);
+  if (EFI_ERROR (Status)) {
+    goto Failed;
+  }
+  if ((Features & VIRTIO_F_VERSION_1) == 0) {
+    Status = EFI_UNSUPPORTED;
+    goto Failed;
+  }
+  //
+  // We only want the most basic 2D features.
+  //
+  Features &= VIRTIO_F_VERSION_1;
+
+  //
+  // ... and write the subset of feature bits understood by the [...] driver to
+  // the device. [...]
+  // 5. Set the FEATURES_OK status bit.
+  // 6. Re-read device status to ensure the FEATURES_OK bit is still set [...]
+  //
+  Status = Virtio10WriteFeatures (VgpuDev->VirtIo, Features, &NextDevStat);
+  if (EFI_ERROR (Status)) {
+    goto Failed;
+  }
+
+  //
+  // 7. Perform device-specific setup, including discovery of virtqueues for
+  // the device [...]
+  //
+  Status = VgpuDev->VirtIo->SetQueueSel (VgpuDev->VirtIo,
+                              VIRTIO_GPU_CONTROL_QUEUE);
+  if (EFI_ERROR (Status)) {
+    goto Failed;
+  }
+  Status = VgpuDev->VirtIo->GetQueueNumMax (VgpuDev->VirtIo, &QueueSize);
+  if (EFI_ERROR (Status)) {
+    goto Failed;
+  }
+
+  //
+  // We implement each VirtIo GPU command that we use with two descriptors:
+  // request, response.
+  //
+  if (QueueSize < 2) {
+    Status = EFI_UNSUPPORTED;
+    goto Failed;
+  }
+
+  //
+  // [...] population of virtqueues [...]
+  //
+  Status = VirtioRingInit (QueueSize, &VgpuDev->Ring);
+  if (EFI_ERROR (Status)) {
+    goto Failed;
+  }
+  Status = VgpuDev->VirtIo->SetQueueAddress (VgpuDev->VirtIo, &VgpuDev->Ring);
+  if (EFI_ERROR (Status)) {
+    goto ReleaseQueue;
+  }
+
+  //
+  // 8. Set the DRIVER_OK status bit.
+  //
+  NextDevStat |= VSTAT_DRIVER_OK;
+  Status = VgpuDev->VirtIo->SetDeviceStatus (VgpuDev->VirtIo, NextDevStat);
+  if (EFI_ERROR (Status)) {
+    goto ReleaseQueue;
+  }
+
+  return EFI_SUCCESS;
+
+ReleaseQueue:
+  VirtioRingUninit (&VgpuDev->Ring);
+
+Failed:
+  //
+  // If any of these steps go irrecoverably wrong, the driver SHOULD set the
+  // FAILED status bit to indicate that it has given up on the device (it can
+  // reset the device later to restart if desired). [...]
+  //
+  // VirtIo access failure here should not mask the original error.
+  //
+  NextDevStat |= VSTAT_FAILED;
+  VgpuDev->VirtIo->SetDeviceStatus (VgpuDev->VirtIo, NextDevStat);
+
+  return Status;
+}
+
+/**
+  De-configure the VirtIo GPU device that underlies VgpuDev.
+
+  @param[in,out] VgpuDev  The VGPU_DEV object to tear down VirtIo messaging
+                          for. On input, the caller is responsible for having
+                          called VirtioGpuInit(). On output, VgpuDev->Ring has
+                          been uninitialized; VirtIo GPU commands (primitives)
+                          can no longer be submitted to the device.
+**/
+VOID
+VirtioGpuUninit (
+  IN OUT VGPU_DEV *VgpuDev
+  )
+{
+  //
+  // Resetting the VirtIo device makes it release its resources and forget its
+  // configuration.
+  //
+  VgpuDev->VirtIo->SetDeviceStatus (VgpuDev->VirtIo, 0);
+  VirtioRingUninit (&VgpuDev->Ring);
+}
+
+/**
+  EFI_EVENT_NOTIFY function for the VGPU_DEV.ExitBoot event. It resets the
+  VirtIo device, causing it to release its resources and to forget its
+  configuration.
+
+  This function may only be called (that is, VGPU_DEV.ExitBoot may only be
+  signaled) after VirtioGpuInit() returns and before VirtioGpuUninit() is
+  called.
+
+  @param[in] Event    Event whose notification function is being invoked.
+
+  @param[in] Context  Pointer to the associated VGPU_DEV object.
+**/
+VOID
+EFIAPI
+VirtioGpuExitBoot (
+  IN EFI_EVENT Event,
+  IN VOID      *Context
+  )
+{
+  VGPU_DEV *VgpuDev;
+
+  VgpuDev = Context;
+  VgpuDev->VirtIo->SetDeviceStatus (VgpuDev->VirtIo, 0);
+}

OvmfPkg/VirtioGpuDxe/DriverBinding.c

@@ -646,13 +646,25 @@ VirtioGpuDriverBindingStart (
       goto FreeVgpuDev;
     }
 
+    Status = VirtioGpuInit (VgpuDev);
+    if (EFI_ERROR (Status)) {
+      goto FreeVgpuDevBusName;
+    }
+
+    Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_CALLBACK,
+                    VirtioGpuExitBoot, VgpuDev /* NotifyContext */,
+                    &VgpuDev->ExitBoot);
+    if (EFI_ERROR (Status)) {
+      goto UninitGpu;
+    }
+
     //
     // Install the VGPU_DEV "protocol interface" on ControllerHandle.
     //
     Status = gBS->InstallProtocolInterface (&ControllerHandle,
                     &gEfiCallerIdGuid, EFI_NATIVE_INTERFACE, VgpuDev);
     if (EFI_ERROR (Status)) {
-      goto FreeVgpuDevBusName;
+      goto CloseExitBoot;
     }
 
     if (RemainingDevicePath != NULL && IsDevicePathEnd (RemainingDevicePath)) {
@@ -693,6 +705,16 @@ UninstallVgpuDev:
            VgpuDev);
   }
 
+CloseExitBoot:
+  if (VirtIoBoundJustNow) {
+    gBS->CloseEvent (VgpuDev->ExitBoot);
+  }
+
+UninitGpu:
+  if (VirtIoBoundJustNow) {
+    VirtioGpuUninit (VgpuDev);
+  }
+
 FreeVgpuDevBusName:
   if (VirtIoBoundJustNow) {
     FreeUnicodeStringTable (VgpuDev->BusName);
@@ -761,6 +783,10 @@ VirtioGpuDriverBindingStop (
                     &gEfiCallerIdGuid, VgpuDev);
     ASSERT_EFI_ERROR (Status);
 
+    Status = gBS->CloseEvent (VgpuDev->ExitBoot);
+    ASSERT_EFI_ERROR (Status);
+
+    VirtioGpuUninit (VgpuDev);
     FreeUnicodeStringTable (VgpuDev->BusName);
     FreePool (VgpuDev);
 

OvmfPkg/VirtioGpuDxe/VirtioGpu.h

@@ -48,6 +48,16 @@ typedef struct {
   //
   EFI_UNICODE_STRING_TABLE *BusName;
 
+  //
+  // VirtIo ring used for VirtIo communication.
+  //
+  VRING                    Ring;
+
+  //
+  // Event to be signaled at ExitBootServices().
+  //
+  EFI_EVENT                ExitBoot;
+
   //
   // The Child field references the GOP wrapper structure. If this pointer is
   // NULL, then the hybrid driver has bound (i.e., started) the
@@ -103,4 +113,62 @@ struct VGPU_GOP_STRUCT {
   UINT8                                Gop;
 };
 
+//
+// VirtIo GPU initialization, and commands (primitives) for the GPU device.
+//
+/**
+  Configure the VirtIo GPU device that underlies VgpuDev.
+
+  @param[in,out] VgpuDev  The VGPU_DEV object to set up VirtIo messaging for.
+                          On input, the caller is responsible for having
+                          initialized VgpuDev->VirtIo. On output, VgpuDev->Ring
+                          has been initialized, and synchronous VirtIo GPU
+                          commands (primitives) can be submitted to the device.
+
+  @retval EFI_SUCCESS      VirtIo GPU configuration successful.
+
+  @retval EFI_UNSUPPORTED  The host-side configuration of the VirtIo GPU is not
+                           supported by this driver.
+
+  @retval                  Error codes from underlying functions.
+**/
+EFI_STATUS
+VirtioGpuInit (
+  IN OUT VGPU_DEV *VgpuDev
+  );
+
+/**
+  De-configure the VirtIo GPU device that underlies VgpuDev.
+
+  @param[in,out] VgpuDev  The VGPU_DEV object to tear down VirtIo messaging
+                          for. On input, the caller is responsible for having
+                          called VirtioGpuInit(). On output, VgpuDev->Ring has
+                          been uninitialized; VirtIo GPU commands (primitives)
+                          can no longer be submitted to the device.
+**/
+VOID
+VirtioGpuUninit (
+  IN OUT VGPU_DEV *VgpuDev
+  );
+
+/**
+  EFI_EVENT_NOTIFY function for the VGPU_DEV.ExitBoot event. It resets the
+  VirtIo device, causing it to release its resources and to forget its
+  configuration.
+
+  This function may only be called (that is, VGPU_DEV.ExitBoot may only be
+  signaled) after VirtioGpuInit() returns and before VirtioGpuUninit() is
+  called.
+
+  @param[in] Event    Event whose notification function is being invoked.
+
+  @param[in] Context  Pointer to the associated VGPU_DEV object.
+**/
+VOID
+EFIAPI
+VirtioGpuExitBoot (
+  IN EFI_EVENT Event,
+  IN VOID      *Context
+  );
+
 #endif // _VIRTIO_GPU_DXE_H_

OvmfPkg/VirtioGpuDxe/VirtioGpu.inf

@@ -24,6 +24,7 @@
   ENTRY_POINT                    = VirtioGpuEntryPoint
 
 [Sources]
+  Commands.c
   DriverBinding.c
   VirtioGpu.h
 
@@ -40,6 +41,7 @@
   UefiBootServicesTableLib
   UefiDriverEntryPoint
   UefiLib
+  VirtioLib
 
 [Protocols]
   gEfiDevicePathProtocolGuid     ## TO_START ## BY_START