On Tue, Dec 05, 2023 at 05:50:27PM +0000, Marc Zyngier wrote: > On Tue, 05 Dec 2023 17:33:01 +0000, > Catalin Marinas <catalin.marinas@xxxxxxx> wrote: > > Ideally we should do this for vfio only but we don't have an easy > > way to convey this to KVM. > > But if we want to limit this to PCIe, we'll have to find out. The > initial proposal (a long while ago) had a flag conveying some > information, and I'd definitely feel more confident having something > like that. We can add a VM_PCI_IO in the high vma flags to be set by vfio_pci_core_mmap(), though it limits it to 64-bit architectures. KVM knows this is PCI and relaxes things a bit. It's not generic though if we need this later for something else. A question for Lorenzo: do these BARs appear in iomem_resource? We could search that up instead of a flag, something like the page_is_ram() helper. -- Catalin
