On Tue, 05 Dec 2023 18:40:42 +0000, Catalin Marinas <catalin.marinas@xxxxxxx> wrote: > > 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. Either that, or something actually describing the attributes that VFIO wants. And I very much want it to be a buy-in behaviour, not something that automagically happens and changes the default behaviour for everyone based on some hand-wavy assertions. If that means a userspace change, fine by me. The VMM better know what is happening. M. -- Without deviation from the norm, progress is not possible.
