Hi Keith, On 03/19/2019 08:21 AM, Keith Busch wrote: > On Tue, Mar 19, 2019 at 04:41:07PM +0200, Maxim Levitsky wrote: >> -> Share the NVMe device between host and guest. >> Even in fully virtualized configurations, >> some partitions of nvme device could be used by guests as block devices >> while others passed through with nvme-mdev to achieve balance between >> all features of full IO stack emulation and performance. >> >> -> NVME-MDEV is a bit faster due to the fact that in-kernel driver >> can send interrupts to the guest directly without a context >> switch that can be expensive due to meltdown mitigation. >> >> -> Is able to utilize interrupts to get reasonable performance. >> This is only implemented >> as a proof of concept and not included in the patches, >> but interrupt driven mode shows reasonable performance >> >> -> This is a framework that later can be used to support NVMe devices >> with more of the IO virtualization built-in >> (IOMMU with PASID support coupled with device that supports it) > > Would be very interested to see the PASID support. You wouldn't even > need to mediate the IO doorbells or translations if assigning entire > namespaces, and should be much faster than the shadow doorbells. > > I think you should send 6/9 "nvme/pci: init shadow doorbell after each > reset" separately for immediate inclusion. > > I like the idea in principle, but it will take me a little time to get > through reviewing your implementation. I would have guessed we could > have leveraged something from the existing nvme/target for the mediating > controller register access and admin commands. Maybe even start with > implementing an nvme passthrough namespace target type (we currently > have block and file). I have the code for the NVMeOf target passthru-ctrl, I think we can use that as it is if you are looking for the passthru for NVMeOF. I'll post patch-series based on the latest code base soon. > > _______________________________________________ > Linux-nvme mailing list > Linux-nvme@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-nvme >
