Il 06/09/2014 01:19, Alexander Graf ha scritto: >> > 1) interpretive execution of pci load/store instruction. If we use this >> > function >> > pci access does not get intercepted (no SIE exit) but is handled via >> > microcode. >> > To enable this we have to disable zpci device and enable it again with >> > information >> > from the SIE control block. > Hrm. So how about you create a special vm ioctl for KVM that allows you > to attach a VFIO device fd into the KVM VM context? Then the default > would stay "accessible by mmap traps", but we could accelerate it with KVM.
There is already KVM_DEV_VFIO_GROUP_ADD and KVM_DEV_VFIO_GROUP_DEL. Right now, they result in a call to kvm_arch_register_noncoherent_dma or kvm_arch_unregister_noncoherent_dma, but you can add more hooks. Paolo
