On 23.09.14 00:28, Alex Williamson wrote: > On Tue, 2014-09-23 at 00:08 +0200, Alexander Graf wrote: >> >> On 22.09.14 22:47, Alex Williamson wrote: >>> On Fri, 2014-09-19 at 13:54 +0200, frank.blaschka@xxxxxxxxxx wrote: >>>> This set of patches implements a vfio based solution for pci >>>> pass-through on the s390 platform. The kernel stuff is pretty >>>> much straight forward, but qemu needs more work. >>>> >>>> Most interesting patch is: >>>> vfio: make vfio run on s390 platform >>>> >>>> I hope Alex & Alex can give me some guidance how to do the changes >>>> in an appropriate way. After creating a separate iommmu address space >>>> for each attached PCI device I can successfully run the vfio type1 >>>> iommu. So If we could extend type1 not registering all guest memory >>>> (see patch) I think we do not need a special vfio iommu for s390 >>>> for the moment. >>>> >>>> The patches implement the base pass-through support. s390 specific >>>> virtualization functions are currently not included. This would >>>> be a second step after the base support is done. >>>> >>>> kernel patches apply to linux-kvm-next >>>> >>>> KVM: s390: Enable PCI instructions >>>> iommu: add iommu for s390 platform >>>> vfio: make vfio build on s390 >>>> >>>> qemu patches apply to qemu-master >>>> >>>> s390: Add PCI bus support >>>> s390: implement pci instruction >>>> vfio: make vfio run on s390 platform >>>> >>>> Thx for feedback and review comments >>> >>> Sending patches as attachments makes it difficult to comment inline. >>> >>> 2/6 >>> - careful of the namespace as you're changing functions from static and >>> exporting them >>> - doesn't seem like functions need to be exported, just non-static to >>> call from s390-iommu.c >>> >>> 6/6 >>> - We shouldn't need to globally disable mmap, each VFIO region reports >>> whether it supports mmap and vfio-pci on s390 should indicate mmap is >>> not supported on the platform. >> >> Can we emulate MMIO on mmap'ed regions by routing every memory access >> via the kernel? It'd be slow, but at least make existing VFIO code >> compatible. > > Isn't that effectively what we do when we use memory_region_init_io() vs > memory_region_init_ram_ptr() or are you suggesting something that can > handle the MMIO without bouncing out to QEMU? VFIO is already > compatible with regions that cannot be mmap'd, the kernel just needs to > report it as such. Thanks, Ah, cool. I guess I missed that part :). Then all is well. Alex -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
