Brijesh Singh 891f016c1b OvmfPkg/VirtioNetDxe: dynamically alloc transmit header
Each network packet is submitted for transmission by pushing the head
descriptor of a two-part descriptor chain to the Available Ring of the
TX queue. VirtioNetInitTx() sets up the the descriptor chains for all
queueable packets in advance, and points all the head descriptors to the
same shared, never modified, VIRTIO_1_0_NET_REQ header object (or its
initial VIRTIO_NET_REQ sub-object, dependent on virtio version).
VirtioNetInitTx() currently uses the header object's system physical
address for populating the head descriptors.

When device is behind the IOMMU, VirtioNet driver is required to provide
the device address of VIRTIO_1_0_NET_REQ header. In this patch we
dynamically allocate the header using AllocateSharedPages() and map with
BusMasterCommonBuffer so that header can be accessed by both processor
and the device.

We map the header object for CommonBuffer operation because, in order to
stick with the current code order, we populate the head descriptors with
the header's device address first, and fill in the header itself second.

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>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
2017-09-14 23:54:10 +02:00
2017-09-06 17:48:03 +01:00
2014-10-14 16:08:15 +00:00

EDK II Project

A modern, feature-rich, cross-platform firmware development environment for the UEFI and PI specifications from www.uefi.org.

Contributions to the EDK II open source project are covered by the TianoCore Contribution Agreement 1.1

The majority of the content in the EDK II open source project uses a BSD 2-Clause License. The EDK II open source project contains the following components that are covered by additional licenses:

The EDK II Project is composed of packages. The maintainers for each package are listed in Maintainers.txt.

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Acidanthera UEFI Development Kit based on EDK II edk2-stable202405
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