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[PATCH 1/1] docs: pcie: describe PCIe option ROMs
From: |
Heinrich Schuchardt |
Subject: |
[PATCH 1/1] docs: pcie: describe PCIe option ROMs |
Date: |
Wed, 20 Jul 2022 08:42:34 +0200 |
Provide a descriptions of the options that control the emulation of option
ROMS for PCIe devices.
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
---
docs/pcie.txt | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/docs/pcie.txt b/docs/pcie.txt
index 89e3502075..a22c1f69f7 100644
--- a/docs/pcie.txt
+++ b/docs/pcie.txt
@@ -292,6 +292,31 @@ PCI-PCI Bridge slots can be used for legacy PCI host
devices.
If you can see the "Express Endpoint" capability in the
output, then the device is indeed PCI Express.
+8. Option ROM
+=============
+PCIe devices may provide an option ROM. The following properties control the
+emulation of the option ROM:
+
+``rombar`` (default: ``1``)
+ Specifies that an option ROM is available. If set to ``0``, no option ROM
+ is present.
+
+``romsize`` (default: ``-1``)
+ Specifies the size of the option ROM in bytes. The value must be either
+ ``-1`` or a power of two. ``-1`` signifies unlimited size.
+
+``romfile``
+ Defines the name of the file to be loaded as option ROM.
+ Some devices like virtio-net-pci define a default file name.
+ The file size may neither exceed 2 GiB nor ``romsize``.
+
+Some QEMU PCIe devices like virtio-net-pci use an option ROM by default. In the
+following example the option ROM of a virtio-net-pci device is disabled. This
+is useful for architectures where QEMU does not supply an option ROM file.
+
+.. code-block:: console
+
+ -device virtio-net-pci,netdev=eth1,mq=on,rombar=0
7. Virtio devices
=================
--
2.36.1
- [PATCH 1/1] docs: pcie: describe PCIe option ROMs,
Heinrich Schuchardt <=