Messages in this thread | | | Date | Wed, 19 Jan 2022 19:10:47 +0100 | Subject | Re: [PATCH v2 00/30] KVM: s390: enable zPCI for interpretive execution | From | Pierre Morel <> |
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On 1/14/22 21:31, Matthew Rosato wrote: > Enable interpretive execution of zPCI instructions + adapter interruption > forwarding for s390x KVM vfio-pci. This is done by introducing a series > of new vfio-pci feature ioctls that are unique vfio-pci-zdev (s390x) and > are used to negotiate the various aspects of zPCI interpretation setup. > 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. > > 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.
I did the comment in a patch but I think that centralizing it here is clearer: I think having a documentation in Documentation/S390 like we have already for VFIO AP and VFIO CCW would be a good thing.
-- Pierre Morel IBM Lab Boeblingen
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