VirtioLib provides an API for simple, synchronous (request/response-style)
virtio communication. The guest driver builds one descriptor chain, link
for link, with VirtioPrepare() and VirtioAppendDesc(), then submits the
chain, and awaits the processing, with VirtioFlush().
The descriptor chain is always built at the beginning of the descriptor
area, with the head descriptor having descriptor index 0.
In order to submit the descriptor chain to the host, the guest always
pushes a new "available element" to the Available Ring, in genuine
queue-like fashion, with the new element referencing the head descriptor
(which always has index 0, see above).
In turn, after processing, the host always pushes a new "used element" to
the Used Ring, in genuine queue-like fashion, with the new element
referencing the head descriptor of the chain that was just processed. The
same element also reports the number of bytes that the host wrote,
consecutively across the host-writeable buffers that were linked by the
descriptors.
(See "OvmfPkg/VirtioNetDxe/TechNotes.txt" for a diagram about the
descriptor area and the rings.)
Because at most one descriptor chain can be in flight with VirtioLib at
any time,
- the Available Ring and the Used Ring proceed in lock-step,
- and the head descriptor that the new "available" and "used" elements can
ever reference has index 0.
Based on the above, we can modify VirtioFlush() to return the number of
bytes written by the host across the descriptor chain. The virtio-block
and virtio-scsi drivers don't care (they have other ways to parse the data
produced by the host), while the virtio-net driver doesn't use
VirtioFlush() at all (it employs VirtioLib only to set up its rings).
However, the virtio entropy device, to be covered in the upcoming
patches, reports the amount of randomness produced by the host only
through this quantity.
Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
(1) VirtioLib allocates the virtio ring in EfiBootServicesData memory.
(This is intentional.) Code that executes after ExitBootServices() is
permitted to reuse such memory.
(2) The hypervisor is allowed to look at, and act upon, a live virtio ring
at any time, even without explicit virtio kicks from the guest.
Should boot loader code or kernel code, running between ExitBootServices()
and the kernel's own virtio drivers resetting the device, overwrite the
pages that used to contain the virtio ring before ExitBootServices(), QEMU
could theoretically interpret that unrelated data as garbage ring
contents, and abort the guest.
Although we have seen no such reports, better be prudent and reset the
device in an ExitBootServices() event handler. Among other things, this
causes QEMU to forget about the device's virtio ring.
Cc: Jordan Justen <jordan.l.justen@intel.com>
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: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18624 6f19259b-4bc3-4df7-8a09-765794883524
UEFI spec virtio spec
======================================= =================================
LowestAlignedLba EFI_LBA (UINT64) alignment_offset u8
+-------------------------------------- +--------------------------------
| first LBA that is aligned to a | offset of first aligned
| physical block boundary (SCSI | logical block
| definition)
LogicalBlocksPerPhysicalBlock UINT32 physical_block_exp u8
+-------------------------------------- +--------------------------------
| number of logical blocks per | # of logical blocks per
| physical block [...] does not contain | physical block (log2)
| an exponential value
OptimalTransferLengthGranularity UINT32 opt_io_size le32
+-------------------------------------- +--------------------------------
| optimal transfer length granularity | optimal (suggested maximum) I/O
| as a number of logical blocks [...] A | size in blocks
| value of 0 means there is no reported
| optimal transfer length granularity
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: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15004 6f19259b-4bc3-4df7-8a09-765794883524
Lines should be no longer than 79 characters.
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: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15003 6f19259b-4bc3-4df7-8a09-765794883524
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: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14968 6f19259b-4bc3-4df7-8a09-765794883524
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: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14966 6f19259b-4bc3-4df7-8a09-765794883524
OvmfPkg/VirtioBlkDxe/VirtioBlk.c:667: undefined reference to `__umoddi3'
OvmfPkg/VirtioBlkDxe/VirtioBlk.c:750: undefined reference to `__udivdi3'
These operations would come from libgcc in the IA32 build, but OVMF does not
link against libgcc.
Regression-tested the X64 build with Fedora 18 Alpha XFCE and Windows 8
Consumer Preview guests.
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: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13846 6f19259b-4bc3-4df7-8a09-765794883524
AppendDesc() should have a prefix implying its containing library,
VirtioLib. Update its sole client VirtioBlkDxe.
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: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13843 6f19259b-4bc3-4df7-8a09-765794883524
Introduce a new library called VirtioLib, for now only collecting the
following reusable functions with as little changes as possible:
- VirtioWrite()
- VirtioRead()
- VirtioRingInit()
- VirtioRingUninit()
- AppendDesc()
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: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13842 6f19259b-4bc3-4df7-8a09-765794883524
Separate virtio-blk related macro and type definitions from generic virtio
related ones. Adapt the virtio-blk driver since it needs the latter too.
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: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13841 6f19259b-4bc3-4df7-8a09-765794883524
since they are in fact virtio-blk specific.
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: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13840 6f19259b-4bc3-4df7-8a09-765794883524
This commit consists of:
- a verbatim move ("similarity index 100%" in git parlance),
- an updated #include directive in VirtioBlkDxe/VirtioBlk.h,
- and an OvmfPkg.dec package entry in VirtioBlkDxe/VirtioBlk.inf, so that
the new include directory is searched.
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: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13836 6f19259b-4bc3-4df7-8a09-765794883524
Laszlo Ersek
Jordan Justen
Olivier Martin
jljusten