Re: [PATCH v1 03/14] OvmfPkg/VirtioPciDeviceDxe: Implement new member functions

[Laszlo Ersek <lersek@redhat.com>]

On 08/07/17 13:58, Brijesh Singh wrote:
> The patch implements the newly added member functions by respectively
> delegating the job to:
> 
> - MemoryApplicationLib.AllocatePages () -- with BootServicesData
> - MemoryApplicationLib.FreePages ()
> - no-op (host address is same as device DMA address)
> - no-op

(1) (2) Please see points (1) and (2) in my "PATCH v1 02/14" feedback.

(3) s/Application/Allocation/

(4) the "with BootServicesData" remark is not needed after the
MemoryAllocationLib.AllocatePages() reference. MemoryAllocationLib
encodes the memory type in the API names. So you have AllocatePool /
AllocatePages, AllocateReservedPool / AllocateReservedPages,
AllocateRuntimePool / AllocateRuntimePages, etc.

Please see the lib class header

MdePkg/Include/Library/MemoryAllocationLib.h

> 
> Suggested-by: Laszlo Ersek <lersek@redhat.com>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Jordan Justen <jordan.l.justen@intel.com>
> Cc: Tom Lendacky <thomas.lendacky@amd.com>
> Cc: Laszlo Ersek <lersek@redhat.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> ---
>  OvmfPkg/VirtioPciDeviceDxe/VirtioPciDevice.h    | 34 ++++++++++
>  OvmfPkg/VirtioPciDeviceDxe/VirtioPciDevice.c    |  7 ++-
>  OvmfPkg/VirtioPciDeviceDxe/VirtioPciFunctions.c | 66 ++++++++++++++++++++
>  3 files changed, 106 insertions(+), 1 deletion(-)
> 
> diff --git a/OvmfPkg/VirtioPciDeviceDxe/VirtioPciDevice.h b/OvmfPkg/VirtioPciDeviceDxe/VirtioPciDevice.h
> index 8f17a16c88f5..da98de123000 100644
> --- a/OvmfPkg/VirtioPciDeviceDxe/VirtioPciDevice.h
> +++ b/OvmfPkg/VirtioPciDeviceDxe/VirtioPciDevice.h
> @@ -3,6 +3,7 @@
>    Internal definitions for the VirtIo PCI Device driver
>  
>    Copyright (C) 2013, ARM Ltd
> +  Copyright (c) 2017, AMD Inc, All rights reserved.<BR>
>  
>    This program and the accompanying materials are licensed and made available
>    under the terms and conditions of the BSD License which accompanies this
> @@ -156,4 +157,37 @@ VirtioPciSetDeviceStatus (
>    UINT8                          DeviceStatus
>    );
>  
> +EFI_STATUS
> +EFIAPI
> +VirtioPciAllocateSharedPages (
> +  VIRTIO_DEVICE_PROTOCOL        *This,
> +  UINTN                         NumPages,
> +  VOID                          **HostAddress
> +  );
> +
> +VOID
> +EFIAPI
> +VirtioPciFreeSharedPages (
> +  VIRTIO_DEVICE_PROTOCOL        *This,
> +  UINTN                         NumPages,
> +  VOID                          *HostAddress
> +  );
> +
> +EFI_STATUS
> +EFIAPI
> +VirtioPciMapSharedBuffer (
> +  VIRTIO_DEVICE_PROTOCOL        *This,
> +  VIRTIO_MAP_OPERATION          Operation,
> +  VOID                          *HostAddress,
> +  UINTN                         *NumberOfBytes,
> +  EFI_PHYSICAL_ADDRESS          *DeviceAddress,
> +  VOID                          **Mapping
> +  );
> +
> +EFI_STATUS
> +EFIAPI
> +VirtioPciUnmapSharedBuffer (
> +  VIRTIO_DEVICE_PROTOCOL        *This,
> +  VOID                          *Mapping
> +  );
>  #endif // _VIRTIO_PCI_DEVICE_DXE_H_
> diff --git a/OvmfPkg/VirtioPciDeviceDxe/VirtioPciDevice.c b/OvmfPkg/VirtioPciDeviceDxe/VirtioPciDevice.c
> index bc4f6fe8bfa3..4e4e21d9a477 100644
> --- a/OvmfPkg/VirtioPciDeviceDxe/VirtioPciDevice.c
> +++ b/OvmfPkg/VirtioPciDeviceDxe/VirtioPciDevice.c
> @@ -5,6 +5,7 @@
>    Copyright (C) 2012, Red Hat, Inc.
>    Copyright (c) 2012 - 2016, Intel Corporation. All rights reserved.<BR>
>    Copyright (C) 2013, ARM Ltd.
> +  Copyright (C) 2017, AMD Inc, All rights reserved.<BR>
>  
>    This program and the accompanying materials are licensed and made available
>    under the terms and conditions of the BSD License which accompanies this
> @@ -40,7 +41,11 @@ STATIC VIRTIO_DEVICE_PROTOCOL mDeviceProtocolTemplate = {
>    VirtioPciGetDeviceStatus,             // GetDeviceStatus
>    VirtioPciSetDeviceStatus,             // SetDeviceStatus
>    VirtioPciDeviceWrite,                 // WriteDevice
> -  VirtioPciDeviceRead                   // ReadDevice
> +  VirtioPciDeviceRead,                  // ReadDevice
> +  VirtioPciAllocateSharedPages,         // AllocateSharedPages
> +  VirtioPciFreeSharedPages,             // FreeSharedPages
> +  VirtioPciMapSharedBuffer,             // MapSharedBuffer
> +  VirtioPciUnmapSharedBuffer,           // UnmapSharedBuffer
>  };
>  
>  /**
> diff --git a/OvmfPkg/VirtioPciDeviceDxe/VirtioPciFunctions.c b/OvmfPkg/VirtioPciDeviceDxe/VirtioPciFunctions.c
> index 243aa14c2421..1c587e184311 100644
> --- a/OvmfPkg/VirtioPciDeviceDxe/VirtioPciFunctions.c
> +++ b/OvmfPkg/VirtioPciDeviceDxe/VirtioPciFunctions.c
> @@ -5,6 +5,7 @@
>    Copyright (C) 2012, Red Hat, Inc.
>    Copyright (c) 2012, Intel Corporation. All rights reserved.<BR>
>    Copyright (C) 2013, ARM Ltd.
> +  Copyright (C) 2017, AMD Inc, All rights reserved.<BR>
>  
>    This program and the accompanying materials are licensed and made available
>    under the terms and conditions of the BSD License which accompanies this
> @@ -271,3 +272,68 @@ VirtioPciSetDeviceStatus (
>    return VirtioPciIoWrite (Dev, VIRTIO_PCI_OFFSET_QUEUE_DEVICE_STATUS,
>        sizeof (UINT8), DeviceStatus);
>  }
> +
> +EFI_STATUS
> +EFIAPI
> +VirtioPciAllocateSharedPages (
> +  VIRTIO_DEVICE_PROTOCOL  *This,
> +  UINTN                   NumPages,
> +  VOID                    **HostAddress
> +  )
> +{
> +  EFI_STATUS              Status;
> +  EFI_PHYSICAL_ADDRESS    PhysicalAddress;
> +
> +  Status = gBS->AllocatePages (
> +                  AllocateAnyPages,
> +                  EfiBootServicesData,
> +                  NumPages,
> +                  &PhysicalAddress
> +                  );
> +  if (!EFI_ERROR (Status)) {
> +    *HostAddress = (VOID *) (UINTN) PhysicalAddress;
> +  }
> +
> +  return Status;
> +}

(5) We might want do what we promise in the commit message :) Namely,
use MemoryAllocationLib APIs (for simplicity), rather than boot
services. Such as:

  VOID *Buffer;

  Buffer = AllocatePages (NumPages);
  if (Buffer == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }
  *HostAddress = Buffer;
  return EFI_SUCCESS;

> +
> +VOID
> +EFIAPI
> +VirtioPciFreeSharedPages (
> +  VIRTIO_DEVICE_PROTOCOL  *This,
> +  UINTN                   NumPages,
> +  VOID                    *HostAddress
> +  )
> +{
> +  gBS->FreePages ((EFI_PHYSICAL_ADDRESS) (UINTN)HostAddress, NumPages);
> +}

(6) Similarly:

  FreePages (HostAddress, NumPages);

> +
> +EFI_STATUS
> +EFIAPI
> +VirtioPciMapSharedBuffer (
> +  VIRTIO_DEVICE_PROTOCOL  *This,
> +  VIRTIO_MAP_OPERATION    Operation,
> +  VOID                    *HostAddress,
> +  UINTN                   *NumberOfBytes,
> +  EFI_PHYSICAL_ADDRESS    *DeviceAddress,
> +  VOID                    **Mapping
> +  )
> +{
> +  EFI_PHYSICAL_ADDRESS    PhysicalAddress;
> +
> +  PhysicalAddress = (EFI_PHYSICAL_ADDRESS) (UINTN) HostAddress;
> +
> +  *DeviceAddress = PhysicalAddress;
> +
> +  return EFI_SUCCESS;
> +}

(7) We could condense it to a single assignment to *DeviceAddress. Up to
you.

(8) Please set *Mapping to NULL -- let's not cause the future caller of
Unmap() to evaluate (for argument passing) a pointer with garbage
contents at that point; that's undefined behavior in itself, at least in
theory.

> +
> +EFI_STATUS
> +EFIAPI
> +VirtioPciUnmapSharedBuffer (
> +  VIRTIO_DEVICE_PROTOCOL    *This,
> +  VOID                      *Mapping
> +  )
> +{
> +  return EFI_SUCCESS;
> +}
> 

(9) Please refresh the function signatures in both "VirtioPciDevice.h"
and "VirtioPciFunctions.c", from the protocol definition in
"OvmfPkg/Include/Protocol/VirtioDevice.h".

In particular, all the IN and OUT decoration is missing here.

To be continued.

Thanks,
Laszlo