On Wed, Apr 11, 2018 at 04:37:16PM +0800, Peter Xu wrote: > On Wed, Apr 11, 2018 at 04:25:56PM +0800, Tiwei Bie wrote: > > On Wed, Apr 11, 2018 at 04:00:36PM +0800, Peter Xu wrote: > > > On Wed, Apr 11, 2018 at 03:20:27PM +0800, Tiwei Bie wrote: > > > > > > [...] > > > > > > > This is just a RFC for now. It seems that, it doesn't work > > > > as expected when guest is using kernel driver (To handle > > > > this case, it seems that some RAM regions' events also need > > > > to be listened). Any comments would be appreciated! Thanks! > > > > > > Hi, Tiwei, > > > > > > What's your kernel command line in the guest? Is iommu=pt there? > > > > Yeah, you are right! The related things in kernel command line are: > > > > iommu=pt intel_iommu=on > > > > Hmm, how will this param affect vIOMMU's behaviour?.. > > If iommu=pt is there, guest kernel will try to bypass IOMMU, the IOMMU > regions will be disabled completely in that case, hence it's very > possible that your IOMMU memory listeners won't get anything useful. > > Maybe you can consider removing iommu=pt in the guest parameter to see > whether the guest kernel driver could work.
Cool. I'll give it a try! Considering we may also need to handle the iommu=pt case, is there any event in QEMU can be used to know whether the IOMMU regions are disabled or enabled by the guest? Best regards, Tiwei Bie > > -- > Peter Xu
