From 68f5d3f3b6543266b29e047cfaf9842333019b4c Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 5 Mar 2021 13:19:58 +0100 Subject: um: add PCI over virtio emulation driver To support testing of PCI/PCIe drivers in UML, add a PCI bus support driver. This driver uses virtio, which in UML is really just vhost-user, to talk to devices, and adds the devices to the virtual PCI bus in the system. Since virtio already allows DMA/bus mastering this really isn't all that hard, of course we need the logic_iomem infrastructure that was added by a previous patch. The protocol to talk to the device is has a few fairly simple messages for reading to/writing from config and IO spaces, and messages for the device to send the various interrupts (INT#, MSI/MSI-X and while suspended PME#). Note that currently no offical virtio device ID is assigned for this protocol, as a consequence this patch requires defining it in the Kconfig, with a default that makes the driver refuse to work at all. Finally, in order to add support for MSI/MSI-X interrupts, some small changes are needed in the UML IRQ code, it needs to have more interrupts, changing NR_IRQS from 64 to 128 if this driver is enabled, but not actually use them for anything so that the generic IRQ domain/MSI infrastructure can allocate IRQ numbers. Signed-off-by: Johannes Berg Signed-off-by: Richard Weinberger --- arch/um/kernel/ioport.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) create mode 100644 arch/um/kernel/ioport.c (limited to 'arch/um/kernel/ioport.c') diff --git a/arch/um/kernel/ioport.c b/arch/um/kernel/ioport.c new file mode 100644 index 000000000000..7220615b3beb --- /dev/null +++ b/arch/um/kernel/ioport.c @@ -0,0 +1,13 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2021 Intel Corporation + * Author: Johannes Berg + */ +#include +#include + +void __iomem *__pci_ioport_map(struct pci_dev *dev, unsigned long port, + unsigned int nr) +{ + return NULL; +} -- cgit