Re: [PATCH v2 7/7] OvmfPkg/Virtio10Dxe: convert to PciCapLib

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On 23 May 2018 at 22:21, Laszlo Ersek <lersek@redhat.com> wrote:
> Replace the manual capability list parsing in OvmfPkg/Virtio10Dxe with
> PciCapLib and PciCapPciIoLib API calls.
>
> The VIRTIO_PCI_CAP_LINK structure type is now superfluous. (Well, it
> always has been; we should have used EFI_PCI_CAPABILITY_HDR.)
>
> Also, EFI_PCI_CAPABILITY_VENDOR_HDR is now included at the front of
> VIRTIO_PCI_CAP. No driver other than Virtio10Dxe relies on VIRTIO_PCI_CAP.
>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Jordan Justen <jordan.l.justen@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>

Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

> ---
>
> Notes:
>     v2:
>     - no changes
>
>  OvmfPkg/Virtio10Dxe/Virtio10.inf            |   2 +
>  OvmfPkg/Include/IndustryStandard/Virtio10.h |   7 +-
>  OvmfPkg/Virtio10Dxe/Virtio10.c              | 135 +++++++-------------
>  3 files changed, 52 insertions(+), 92 deletions(-)
>
> diff --git a/OvmfPkg/Virtio10Dxe/Virtio10.inf b/OvmfPkg/Virtio10Dxe/Virtio10.inf
> index c4ef15d94bfc..db0cb1189a29 100644
> --- a/OvmfPkg/Virtio10Dxe/Virtio10.inf
> +++ b/OvmfPkg/Virtio10Dxe/Virtio10.inf
> @@ -32,6 +32,8 @@ [LibraryClasses]
>    BaseMemoryLib
>    DebugLib
>    MemoryAllocationLib
> +  PciCapLib
> +  PciCapPciIoLib
>    UefiBootServicesTableLib
>    UefiDriverEntryPoint
>    UefiLib
> diff --git a/OvmfPkg/Include/IndustryStandard/Virtio10.h b/OvmfPkg/Include/IndustryStandard/Virtio10.h
> index c5efb5cfcb8a..7d51aa36b326 100644
> --- a/OvmfPkg/Include/IndustryStandard/Virtio10.h
> +++ b/OvmfPkg/Include/IndustryStandard/Virtio10.h
> @@ -16,6 +16,7 @@
>  #ifndef _VIRTIO_1_0_H_
>  #define _VIRTIO_1_0_H_
>
> +#include <IndustryStandard/Pci23.h>
>  #include <IndustryStandard/Virtio095.h>
>
>  //
> @@ -29,11 +30,7 @@
>  //
>  #pragma pack (1)
>  typedef struct {
> -  UINT8 CapId;   // Capability identifier (generic)
> -  UINT8 CapNext; // Link to next capability (generic)
> -} VIRTIO_PCI_CAP_LINK;
> -
> -typedef struct {
> +  EFI_PCI_CAPABILITY_VENDOR_HDR VendorHdr;
>    UINT8  ConfigType; // Identifies the specific VirtIo 1.0 config structure
>    UINT8  Bar;        // The BAR that contains the structure
>    UINT8  Padding[3];
> diff --git a/OvmfPkg/Virtio10Dxe/Virtio10.c b/OvmfPkg/Virtio10Dxe/Virtio10.c
> index e9b50b6e437b..9ebb72c76bfd 100644
> --- a/OvmfPkg/Virtio10Dxe/Virtio10.c
> +++ b/OvmfPkg/Virtio10Dxe/Virtio10.c
> @@ -21,6 +21,8 @@
>  #include <Library/BaseMemoryLib.h>
>  #include <Library/DebugLib.h>
>  #include <Library/MemoryAllocationLib.h>
> +#include <Library/PciCapLib.h>
> +#include <Library/PciCapPciIoLib.h>
>  #include <Library/UefiBootServicesTableLib.h>
>  #include <Library/UefiLib.h>
>
> @@ -184,48 +186,6 @@ GetBarType (
>  }
>
>
> -/**
> -  Read a slice from PCI config space at the given offset, then advance the
> -  offset.
> -
> -  @param [in]     PciIo   The EFI_PCI_IO_PROTOCOL instance that represents the
> -                          device.
> -
> -  @param [in,out] Offset  On input, the offset in PCI config space to start
> -                          reading from. On output, the offset of the first byte
> -                          that was not read. On error, Offset is not modified.
> -
> -  @param [in]     Size    The number of bytes to read.
> -
> -  @param [out]    Buffer  On output, the bytes read from PCI config space are
> -                          stored in this object.
> -
> -  @retval EFI_SUCCESS  Size bytes have been transferred from PCI config space
> -                       (from Offset) to Buffer, and Offset has been incremented
> -                       by Size.
> -
> -  @return              Error codes from PciIo->Pci.Read().
> -**/
> -STATIC
> -EFI_STATUS
> -ReadConfigSpace (
> -  IN     EFI_PCI_IO_PROTOCOL *PciIo,
> -  IN OUT UINT32              *Offset,
> -  IN     UINTN               Size,
> -     OUT VOID                *Buffer
> -  )
> -{
> -  EFI_STATUS Status;
> -
> -  Status = PciIo->Pci.Read (PciIo, EfiPciIoWidthUint8, *Offset, Size, Buffer);
> -  if (EFI_ERROR (Status)) {
> -    return Status;
> -  }
> -  *Offset += (UINT32)Size;
> -  return EFI_SUCCESS;
> -}
> -
> -
>  /*
>    Traverse the PCI capabilities list of a virtio-1.0 device, and capture the
>    locations of the interesting virtio-1.0 register blocks.
> @@ -239,57 +199,51 @@ ReadConfigSpace (
>                                  will have been updated from the PCI
>                                  capabilities found.
>
> -  @param[in]     CapabilityPtr  The offset of the first capability in PCI
> -                                config space, taken from the standard PCI
> -                                device header.
> -
>    @retval EFI_SUCCESS  Traversal successful.
>
> -  @return              Error codes from the ReadConfigSpace() and GetBarType()
> -                       helper functions.
> +  @return              Error codes from PciCapPciIoLib, PciCapLib, and the
> +                       GetBarType() helper function.
>  */
>  STATIC
>  EFI_STATUS
>  ParseCapabilities (
> -  IN OUT VIRTIO_1_0_DEV *Device,
> -  IN     UINT8          CapabilityPtr
> +  IN OUT VIRTIO_1_0_DEV *Device
>    )
>  {
> -  UINT32              Offset;
> -  VIRTIO_PCI_CAP_LINK CapLink;
> +  EFI_STATUS   Status;
> +  PCI_CAP_DEV  *PciDevice;
> +  PCI_CAP_LIST *CapList;
> +  UINT16       VendorInstance;
> +  PCI_CAP      *VendorCap;
>
> -  for (Offset = CapabilityPtr & 0xFC;
> -       Offset > 0;
> -       Offset = CapLink.CapNext & 0xFC
> -       ) {
> -    EFI_STATUS        Status;
> +  Status = PciCapPciIoDeviceInit (Device->PciIo, &PciDevice);
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +  Status = PciCapListInit (PciDevice, &CapList);
> +  if (EFI_ERROR (Status)) {
> +    goto UninitPciDevice;
> +  }
> +
> +  for (VendorInstance = 0;
> +       !EFI_ERROR (PciCapListFindCap (CapList, PciCapNormal,
> +                     EFI_PCI_CAPABILITY_ID_VENDOR, VendorInstance,
> +                     &VendorCap));
> +       VendorInstance++) {
>      UINT8             CapLen;
>      VIRTIO_PCI_CAP    VirtIoCap;
>      VIRTIO_1_0_CONFIG *ParsedConfig;
>
> -    //
> -    // Read capability identifier and link to next capability.
> -    //
> -    Status = ReadConfigSpace (Device->PciIo, &Offset, sizeof CapLink,
> -               &CapLink);
> -    if (EFI_ERROR (Status)) {
> -      return Status;
> -    }
> -    if (CapLink.CapId != 0x09) {
> -      //
> -      // Not a vendor-specific capability, move to the next one.
> -      //
> -      continue;
> -    }
> -
>      //
>      // Big enough to accommodate a VIRTIO_PCI_CAP structure?
>      //
> -    Status = ReadConfigSpace (Device->PciIo, &Offset, sizeof CapLen, &CapLen);
> +    Status = PciCapRead (PciDevice, VendorCap,
> +               OFFSET_OF (EFI_PCI_CAPABILITY_VENDOR_HDR, Length), &CapLen,
> +               sizeof CapLen);
>      if (EFI_ERROR (Status)) {
> -      return Status;
> +      goto UninitCapList;
>      }
> -    if (CapLen < sizeof CapLink + sizeof CapLen + sizeof VirtIoCap) {
> +    if (CapLen < sizeof VirtIoCap) {
>        //
>        // Too small, move to next.
>        //
> @@ -299,11 +253,11 @@ ParseCapabilities (
>      //
>      // Read interesting part of capability.
>      //
> -    Status = ReadConfigSpace (Device->PciIo, &Offset, sizeof VirtIoCap,
> -               &VirtIoCap);
> +    Status = PciCapRead (PciDevice, VendorCap, 0, &VirtIoCap, sizeof VirtIoCap);
>      if (EFI_ERROR (Status)) {
> -      return Status;
> +      goto UninitCapList;
>      }
> +
>      switch (VirtIoCap.ConfigType) {
>      case VIRTIO_PCI_CAP_COMMON_CFG:
>        ParsedConfig = &Device->CommonConfig;
> @@ -326,7 +280,7 @@ ParseCapabilities (
>      //
>      Status = GetBarType (Device->PciIo, VirtIoCap.Bar, &ParsedConfig->BarType);
>      if (EFI_ERROR (Status)) {
> -      return Status;
> +      goto UninitCapList;
>      }
>      ParsedConfig->Bar    = VirtIoCap.Bar;
>      ParsedConfig->Offset = VirtIoCap.Offset;
> @@ -337,19 +291,18 @@ ParseCapabilities (
>        // This capability has an additional field called NotifyOffsetMultiplier;
>        // parse it too.
>        //
> -      if (CapLen < sizeof CapLink + sizeof CapLen + sizeof VirtIoCap +
> -                   sizeof Device->NotifyOffsetMultiplier) {
> +      if (CapLen < sizeof VirtIoCap + sizeof Device->NotifyOffsetMultiplier) {
>          //
>          // Too small, move to next.
>          //
>          continue;
>        }
>
> -      Status = ReadConfigSpace (Device->PciIo, &Offset,
> -                 sizeof Device->NotifyOffsetMultiplier,
> -                 &Device->NotifyOffsetMultiplier);
> +      Status = PciCapRead (PciDevice, VendorCap, sizeof VirtIoCap,
> +                 &Device->NotifyOffsetMultiplier,
> +                 sizeof Device->NotifyOffsetMultiplier);
>        if (EFI_ERROR (Status)) {
> -        return Status;
> +        goto UninitCapList;
>        }
>      }
>
> @@ -359,7 +312,15 @@ ParseCapabilities (
>      ParsedConfig->Exists = TRUE;
>    }
>
> -  return EFI_SUCCESS;
> +  ASSERT_EFI_ERROR (Status);
> +
> +UninitCapList:
> +  PciCapListUninit (CapList);
> +
> +UninitPciDevice:
> +  PciCapPciIoDeviceUninit (PciDevice);
> +
> +  return Status;
>  }
>
>
> @@ -1015,7 +976,7 @@ Virtio10BindingStart (
>
>    Device->VirtIo.SubSystemDeviceId = Pci.Hdr.DeviceId - 0x1040;
>
> -  Status = ParseCapabilities (Device, Pci.Device.CapabilityPtr);
> +  Status = ParseCapabilities (Device);
>    if (EFI_ERROR (Status)) {
>      goto ClosePciIo;
>    }
> --
> 2.14.1.3.gb7cf6e02401b
>