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/include/asm/irq.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'arch/um/include/asm/irq.h') diff --git a/arch/um/include/asm/irq.h b/arch/um/include/asm/irq.h index 3f5d3e8228fc..e187c789369d 100644 --- a/arch/um/include/asm/irq.h +++ b/arch/um/include/asm/irq.h @@ -31,7 +31,13 @@ #endif -#define NR_IRQS 64 +#define UM_LAST_SIGNAL_IRQ 64 +/* If we have (simulated) PCI MSI, allow 64 more interrupt numbers for it */ +#ifdef CONFIG_PCI_MSI +#define NR_IRQS (UM_LAST_SIGNAL_IRQ + 64) +#else +#define NR_IRQS UM_LAST_SIGNAL_IRQ +#endif /* CONFIG_PCI_MSI */ #include #endif -- cgit v1.2.3