Messages in this thread | | | Date | Mon, 14 Mar 2022 15:52:38 -0400 | Subject | Re: [PATCH v4 00/32] KVM: s390: enable zPCI for interpretive execution | From | Matthew Rosato <> |
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On 3/14/22 3:44 PM, Matthew Rosato wrote: > Note: A few patches in this series are dependent on Baolu's IOMMU domain ops > split, which is currently in the next branch of linux-iommu. This series > applies on top: > https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git > > Enable interpretive execution of zPCI instructions + adapter interruption > forwarding for s390x KVM vfio-pci. This is done by introducing a new IOMMU > domain for s390x (KVM-managed), indicating via vfio that this IOMMU domain > should be used instead of the default, with subsequent management of the > hardware assists being handled via a new KVM ioctl for zPCI management. > > By allowing intepretation of zPCI instructions and firmware delivery of > interrupts to guests, we can significantly reduce the frequency of guest > SIE exits for zPCI. We then see additional gains by handling a hot-path > instruction that can still intercept to the hypervisor (RPCIT) directly > in kvm via the new IOMMU domain, whose map operations update the host > DMA table with pinned guest entries over the specified range. > > From the perspective of guest configuration, you passthrough zPCI devices > in the same manner as before, with intepretation support being used by > default if available in kernel+qemu. > > Will reply with a link to the associated QEMU series.
QEMU series: https://lore.kernel.org/kvm/20220314194920.58888-1-mjrosato@linux.ibm.com/
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