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Can this work? Thanks, > > Host crashing stuff is a different issue, I think the plan was to > revoke the entire MMIO space from userspace and remove it from the > kernel mapping. Entire because we don't want to parse the TDISP report > to figure out something more narrow. > > Therefore there is no way the host can crash. Ah ok. > When qemu constructs the VM memory map it already has a scheme to > insert a hole for a SW emulated page for MSI. That will keep working > exactly as it is. > > When the VM validates the MMIO the hole has to fall within a T=0 space > of the TDISP report or the VM will reject it. > > This means devices need to have a T=0 hole around their MSI-X/etc > suitable for a 64K page size OS. Since we are ditching mappings, the entire MSIX-containing 64K block will be ioctl()ed instead of directly accessed from QEMU via mmap (which is slower the VM direct access but still)? > This is already the case, if a device mixes MSIx with other things > qemu will work but it becomes horribly slow and a little broken. Really only when MSIX is not system page size aligned but yeah, I had enough of that with PPC. Thanks, > > Jason -- Alexey