On 08/23/17 14:22, Brijesh Singh wrote:
> The patch extends VIRTIO_DEVICE_PROTOCOL to provide the following new
> member functions:
>
> - AllocateSharedPages : allocate a memory region suitable for sharing
> between guest and hypervisor (e.g ring buffer).
>
> - FreeSharedPages: free the memory allocated using AllocateSharedPages ().
>
> - MapSharedBuffer: map a host address to device address suitable to share
> with device for bus master operations.
>
> - UnmapSharedBuffer: unmap the device address obtained through the
> MapSharedBuffer().
>
> We're free to extend the protocol structure without changing the protocol
> GUID, or bumping any protocol version fields (of which we currently have
> none), because VIRTIO_DEVICE_PROTOCOL is internal to edk2 by design --
> see the disclaimers in "VirtioDevice.h".
>
> The patch implements Laszlo's recommendation [1].
>
> [1] http://mid.mail-archive.com/841bec5f-6f6e-8b1f-25ba-0fd37a915b72@redhat.com
>
> 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/Include/Protocol/VirtioDevice.h | 143 ++++++++++++++++++++
> 1 file changed, 143 insertions(+)
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Thanks!
Laszlo
> diff --git a/OvmfPkg/Include/Protocol/VirtioDevice.h b/OvmfPkg/Include/Protocol/VirtioDevice.h
> index fc166bd1a2b4..9a01932958a2 100644
> --- a/OvmfPkg/Include/Protocol/VirtioDevice.h
> +++ b/OvmfPkg/Include/Protocol/VirtioDevice.h
> @@ -5,6 +5,7 @@
> and should not be used outside of the EDK II tree.
>
> Copyright (c) 2013, ARM Ltd. All rights reserved.<BR>
> + 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
> @@ -33,6 +34,25 @@
>
> typedef struct _VIRTIO_DEVICE_PROTOCOL VIRTIO_DEVICE_PROTOCOL;
>
> +//
> +// VIRTIO Operation for VIRTIO_MAP_SHARED
> +//
> +typedef enum {
> + //
> + // A read operation from system memory by a bus master
> + //
> + VirtioOperationBusMasterRead,
> + //
> + // A write operation to system memory by a bus master
> + //
> + VirtioOperationBusMasterWrite,
> + //
> + // Provides both read and write access to system memory by both the
> + // processor and a bus master
> + //
> + VirtioOperationBusMasterCommonBuffer,
> +} VIRTIO_MAP_OPERATION;
> +
> /**
>
> Read a word from the device-specific I/O region of the Virtio Header.
> @@ -321,6 +341,121 @@ EFI_STATUS
> IN UINT8 DeviceStatus
> );
>
> +/**
> +
> + Allocates pages that are suitable for an VirtioOperationBusMasterCommonBuffer
> + mapping. This means that the buffer allocated by this function supports
> + simultaneous access by both the processor and the bus master. The device
> + address that the bus master uses to access the buffer must be retrieved with
> + a call to VIRTIO_MAP_SHARED.
> +
> + @param[in] This The protocol instance pointer.
> +
> + @param[in] Pages The number of pages to allocate.
> +
> + @param[in,out] HostAddress A pointer to store the system memory base
> + address of the allocated range.
> +
> + @retval EFI_SUCCESS The requested memory pages were allocated.
> + @retval EFI_OUT_OF_RESOURCES The memory pages could not be allocated.
> +
> +**/
> +typedef
> +EFI_STATUS
> +(EFIAPI *VIRTIO_ALLOCATE_SHARED)(
> + IN VIRTIO_DEVICE_PROTOCOL *This,
> + IN UINTN Pages,
> + IN OUT VOID **HostAddress
> + );
> +
> +/**
> + Frees memory that was allocated with VIRTIO_ALLOCATE_SHARED.
> +
> + @param[in] This The protocol instance pointer.
> +
> + @param[in] Pages The number of pages to free.
> +
> + @param[in] HostAddress The system memory base address of the allocated
> + range.
> +
> +**/
> +typedef
> +VOID
> +(EFIAPI *VIRTIO_FREE_SHARED)(
> + IN VIRTIO_DEVICE_PROTOCOL *This,
> + IN UINTN Pages,
> + IN VOID *HostAddress
> + );
> +
> +/**
> + Provides the virtio device address required to access system memory from a
> + DMA bus master.
> +
> + The interface follows the same usage pattern as defined in UEFI spec 2.6
> + (Section 13.2 PCI Root Bridge I/O Protocol)
> +
> + @param[in] This The protocol instance pointer.
> +
> + @param[in] Operation Indicates if the bus master is going to
> + read or write to system memory.
> +
> + @param[in] HostAddress The system memory address to map to shared
> + buffer address.
> +
> + @param[in,out] NumberOfBytes On input the number of bytes to map.
> + On output the number of bytes that were
> + mapped.
> +
> + @param[out] DeviceAddress The resulting shared map address for the
> + bus master to access the hosts HostAddress.
> +
> + @param[out] Mapping A resulting token to pass to
> + VIRTIO_UNMAP_SHARED.
> +
> + @retval EFI_SUCCESS The range was mapped for the returned
> + NumberOfBytes.
> + @retval EFI_UNSUPPORTED The HostAddress cannot be mapped as a
> + common buffer.
> + @retval EFI_INVALID_PARAMETER One or more parameters are invalid.
> + @retval EFI_OUT_OF_RESOURCES The request could not be completed due to
> + a lack of resources.
> + @retval EFI_DEVICE_ERROR The system hardware could not map the
> + requested address.
> +**/
> +
> +typedef
> +EFI_STATUS
> +(EFIAPI *VIRTIO_MAP_SHARED) (
> + IN VIRTIO_DEVICE_PROTOCOL *This,
> + IN VIRTIO_MAP_OPERATION Operation,
> + IN VOID *HostAddress,
> + IN OUT UINTN *NumberOfBytes,
> + OUT EFI_PHYSICAL_ADDRESS *DeviceAddress,
> + OUT VOID **Mapping
> + );
> +
> +/**
> + Completes the VIRTIO_MAP_SHARED operation and releases any corresponding
> + resources.
> +
> + @param[in] This The protocol instance pointer.
> +
> + @param[in] Mapping The mapping token returned from
> + VIRTIO_MAP_SHARED.
> +
> + @retval EFI_SUCCESS The range was unmapped.
> + @retval EFI_INVALID_PARAMETER Mapping is not a value that was returned by
> + VIRTIO_MAP_SHARED. Passing an invalid Mapping
> + token can cause undefined behavior.
> + @retval EFI_DEVICE_ERROR The data was not committed to the target
> + system memory.
> +**/
> +typedef
> +EFI_STATUS
> +(EFIAPI *VIRTIO_UNMAP_SHARED)(
> + IN VIRTIO_DEVICE_PROTOCOL *This,
> + IN VOID *Mapping
> + );
>
> ///
> /// This protocol provides an abstraction over the VirtIo transport layer
> @@ -361,6 +496,14 @@ struct _VIRTIO_DEVICE_PROTOCOL {
> //
> VIRTIO_DEVICE_WRITE WriteDevice;
> VIRTIO_DEVICE_READ ReadDevice;
> +
> + //
> + // Functions to allocate, free, map and unmap shared buffer
> + //
> + VIRTIO_ALLOCATE_SHARED AllocateSharedPages;
> + VIRTIO_FREE_SHARED FreeSharedPages;
> + VIRTIO_MAP_SHARED MapSharedBuffer;
> + VIRTIO_UNMAP_SHARED UnmapSharedBuffer;
> };
>
> extern EFI_GUID gVirtioDeviceProtocolGuid;
>
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