OvmfPkg/VirtioDevice.h: Introduced VIRTIO_DEVICE_PROTOCOL protocol

This protocol introduces an abstraction to access the VirtIo
Configuration and Device spaces.
The registers in these spaces are located at a different offset and have
a different width whether the transport layer is either PCI or MMIO. This
protocol would also allow to support VirtIo PCI devices with MSI-X
capability in a transparent way (Device space is at a different offset
when a PCIe device has MSI-X capability).

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Olivier Martin <olivier.martin@arm.com>

v5:
- add disclaimer (two instances) about the protocol being work in progress

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: svn://svn.code.sf.net/p/edk2/code/trunk/edk2/OvmfPkg@14963 6f19259b-4bc3-4df7-8a09-765794883524
OvmfPkg/VirtioPciDeviceDxe: Implement VIRTIO_DEVICE_PROTOCOL for VirtIo Devices over PCI

This change implements the VIRTIO_DEVICE_PROTOCOL for the PCI transport
layer.
The VirtIo device drivers will interact with the PCI-based VirtIo devices
through this protocol implementation.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Olivier Martin <olivier.martin@arm.com>

v5:
- updated comment block on VirtioPciDeviceRead()
- return EFI_UNSUPPORTED instead of failed ASSERT() in
  VirtioPciSetPageSize()
- VirtioPciIoRead(): restore the original requirement that FieldSize equal
  BufferSize exactly (not only divide it). The looping added in v4 did not
  match the comment block, and the only place that used it in v4 (ie.
  VirtioNetGetFeatures()) needs an open-coded loop anyway (will be done in
  a later part of v5).

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: svn://svn.code.sf.net/p/edk2/code/trunk/edk2/OvmfPkg@14964 6f19259b-4bc3-4df7-8a09-765794883524
OvmfPkg/VirtioMmioDeviceLib: Implement VIRTIO_DEVICE_PROTOCOL for VirtIo Devices over MMIO

Why is the virtio-mmio implementation of the protocol a library,
instead of a driver binary?
The UEFI driver model would encourage to create a virtio-mmio driver
instead of a library. But the reasons why I created a library are:

- A virtio-mmio driver would imply an additional protocol that would
probably have a single attribute field:

typedef struct {
  PHYSICAL_ADDRESS       BaseAddress;
} VIRTIO_MMIO_DEVICE_PROTOCOL;

- There is no (easy) way to scan the available VirtIo devices on a
platform. So, the UEFI firmware for this platform would need a driver
to produce instances for every virtio devices it wants to expose in
UEFI. A single call to a helper library (ie: VirtioMmioDeviceLib)
make the porting easier.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Olivier Martin <olivier.martin@arm.com>

v5:
- typo fix in VirtioMmioInstallDevice() comment block
- plug MmioDevice leak in VirtioMmioUninstallDevice()
- return EFI_INVALID_PARAMETER in VirtioMmioGetQueueAddress() if
  QueueAddress is NULL
- VirtioMmioSetQueueSize(): fix return value (it's a status code)
- VirtioMmioSetPageSize(): check against EFI_PAGE_SIZE with "if" plus
  EFI_UNSUPPORTED, rather than ASSERT()
- VirtioMmioDeviceWrite(), VirtioMmioDeviceRead(): remove redundant
  (FieldSize > 8) checks
- VirtioMmioDeviceLib.inf: drop UefiDriverEntryPoint library dependency

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: svn://svn.code.sf.net/p/edk2/code/trunk/edk2/OvmfPkg@14965 6f19259b-4bc3-4df7-8a09-765794883524
OvmfPkg: Make the VirtIo devices use the new VIRTIO_DEVICE_PROTOCOL

This change replaces the accesses to the PCI bus from the Block, Scsi and Net drivers by
the use of the new VIRTIO_DEVICE_PROTOCOL protocol that abstracts the transport layer.
It means these drivers can be used on PCI and MMIO transport layer.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Olivier Martin <olivier.martin@arm.com>

v5:
- VirtioFlush(): update comment block in VirtioLib.[hc]; error code is
  propagated from VirtIo->SetQueueNotify().
- VirtioBlkInit(): jump to Failed label if SetPageSize() fails
- VirtioBlkInit(): fixup comment, and add error handling, near
  SetQueueNum() call
- VirtioBlkDriverBindingStart(): remove redundant (always false) check for
  a subsystem device ID different from VIRTIO_SUBSYSTEM_BLOCK_DEVICE;
  VirtioBlkDriverBindingSupported() handles it already
- VirtioNetGetFeatures(): update stale comment block
- VirtioNetGetFeatures(): retrieve MAC address byte for byte (open-coded
  loop)
- VirtioNetDriverBindingStart(): remove redundant (always false) check for
  a subsystem device ID different from VIRTIO_SUBSYSTEM_NETWORK_CARD;
  VirtioNetDriverBindingSupported() handles it already
- VirtioNetInitRing(): call SetQueueNum() and SetQueueAlign() for proper
  MMIO operation
- VirtioNetInitialize(): fix destination error label for when
  SetPageSize() fails
- VirtioScsi.c: fix comment block of VIRTIO_CFG_WRITE()/VIRTIO_CFG_READ()
- VirtioScsiInit(): fix destination error label for when SetPageSize()
  fails
- VirtioScsiInit(): call SetQueueNum() and SetQueueAlign() for proper MMIO
  operation

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: svn://svn.code.sf.net/p/edk2/code/trunk/edk2/OvmfPkg@14966 6f19259b-4bc3-4df7-8a09-765794883524
OvmfPkg/Virtio.h: Removed definition of VIRTIO_HDR

This definition is specific to VirtIo over PCI.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Olivier Martin <olivier.martin@arm.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>

git-svn-id: svn://svn.code.sf.net/p/edk2/code/trunk/edk2/OvmfPkg@14967 6f19259b-4bc3-4df7-8a09-765794883524
OvmfPkg/Virtio: Removed VirtioReadDevice() / VirtIoWriteDevice() functions

These functions did not provide much more than the new protocol functions
VIRTIO_DEVICE_PROTOCOL.ReadDevice() / VIRTIO_DEVICE_PROTOCOL.WriteDevice().

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Olivier Martin <olivier.martin@arm.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>

git-svn-id: svn://svn.code.sf.net/p/edk2/code/trunk/edk2/OvmfPkg@14968 6f19259b-4bc3-4df7-8a09-765794883524