Hi Jean, On 8/27/21 3:26 PM, Jean-Philippe Brucker wrote: > 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(). yes that what I meant sorry. > >> 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?
you may add an entry in qemu-options.hx too as Peter did for the intel iommu in 7395b3e3e7 docs: Add '-device intel-iommu' entry (7 weeks ago) <Peter Xu> Thanks Eric > > Thanks, > Jean >
