On Tue, 2019-03-19 at 23:49 +0000, Chaitanya Kulkarni wrote: > 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. I am very intersing in this code. Could you explain how your NVMeOF target passthrough works? Which components of the NVME stack does it involve? Best regards, Maxim Levitsky > > > > _______________________________________________ > > Linux-nvme mailing list > > Linux-nvme@xxxxxxxxxxxxxxxxxxx > > http://lists.infradead.org/mailman/listinfo/linux-nvme > > > > > _______________________________________________ > Linux-nvme mailing list > Linux-nvme@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-nvme
