On Tue, Aug 17, 2021 at 04:11:49PM +0200, Eric Auger wrote: > Hi Jean, > > On 8/10/21 10:45 AM, Jean-Philippe Brucker wrote: > > From: Eric Auger <[email protected]> > > > > Add a hotplug handler for virtio-iommu on x86 and set the necessary > > reserved region property. On x86, the [0xfee00000, 0xfeefffff] DMA > > region is reserved for MSIs. DMA transactions to this range either > > trigger IRQ remapping in the IOMMU or bypasses IOMMU translation. > > > > Although virtio-iommu does not support IRQ remapping it must be informed > > of the reserved region so that it can forward DMA transactions targeting > > this region. > > > > Signed-off-by: Eric Auger <[email protected]> > > Signed-off-by: Jean-Philippe Brucker <[email protected]> > > I think we need to handle the case where the end-user gets lost with > iommu options and use an invalid combination such as > > -M q35,iommu=on,int_remap=on,kernel_irqchip=off -device -device > virtio-iommu-pci
I guess that would be "-M q35,kernel_irqchip=off -device intel-iommu,intremap=on -device virtio-iommu-pci" I'll add the checks, similar to the one in x86_iommu_set_default(). > We may also document somewhere that the virtio-iommu-pci > does not support irq remapping as this may be an important limitation on x86. I'll mention it in the commit message, unless you had another place in mind? Thanks, Jean
