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DescriptionEduardo Habkost
2020-06-25 21:54:22 UTC
This bug was initially created as a copy of libvirt Bug #1717611. qemu-kvm doesn't provide this information, so we need to implement an interface that libvirt can use to query hyperv enlightenments supported by the host.
I suggest using the existing CPU feature query interface for this (query-cpu-model-expansion type=full with model="host" and model="max").
Original bug #1717611 description:
Management software needs to be able to query which HyperV Enlightenments are supported by the current host. The availability of HyperV Enlightenments depends on capabilities available in the KVM kernel module, in QEMU, and in libvirt.
This is supposed to work, but doesn't seem to work today:
query-cpu-model-expansion type=full model={"name":"host","props":{"hv-passthrough":true}}
Probably because hv_cpuid_check_and_set() isn't called at feature expansion time.
We have all the required bits upstream but the series is quite big and I was wondering if it would make sense to try to backport this for 8.5 or not.
Eduardo, are you aware of any particular users of this new interface? In particular, do you know if libvirt is working on a related feature?
(In reply to Vitaly Kuznetsov from comment #9)
> We have all the required bits upstream but the series is quite big and I was
> wondering if it would make sense to try to backport this for 8.5 or not.
>
> Eduardo, are you aware of any particular users of this new interface? In
> particular, do you know if libvirt is working on a related feature?
I don't think we need it in 8.5. We were not planning to use this interface in 8.5 because we thought the hyperv=on boolean (bug 1877467) would work for us.
The libvirt side of this feature is being tracked at bug 1717611.
Comment 11Vitaly Kuznetsov
2021-07-19 07:52:14 UTC
(In reply to Eduardo Habkost from comment #10)
>
> I don't think we need it in 8.5. We were not planning to use this interface
> in 8.5 because we thought the hyperv=on boolean (bug 1877467) would work for
> us.
OK, I'm not backporting patches then, we'll get them with the next rebase. Thanks!
Bulk update: Move RHEL-AV bugs to RHEL9. If necessary to resolve in RHEL8, then clone to the current RHEL8 release.
Comment 13menli@redhat.com
2021-11-25 06:06:04 UTC
Hi Vitaly，
Whether we could move this bug to modify status, as it already works on qemu 6.1. or still wait for other related patch?
details:
qemp command:
{ "execute":"query-cpu-model-expansion","arguments":{"type":"full","model":{"name":"host","props":{"hv-passthrough":true}}}}
test on qemu-kvm-6.1.0-1.module+el8.6.0+12721+8d053ff2.x86_64 before, the result is like: '.."hv-relaxed": true, "avx512-fp16": false, "hv-crash": true,..'
also try it on qemu-kvm-4.2.0-59.module+el8.5.0+12817+cb650d43.x86_64 , the result is like: '.."hv-relaxed": false, "hv-crash": false..'
Thanks
Menghuan
Comment 15Vitaly Kuznetsov
2021-11-25 10:06:37 UTC
(In reply to menli from comment #13)
> Hi Vitaly，
>
> Whether we could move this bug to modify status, as it already works on qemu
> 6.1.
Yes, let's make this TestOnly dependent on QEMU rebase to 6.1 BZ and move to ON_QA.
Comment 16menli@redhat.com
2021-11-25 10:59:03 UTC
Comment 17RHEL Program Management
2021-12-25 07:26:57 UTC
After evaluating this issue, there are no plans to address it further or fix it in an upcoming release. Therefore, it is being closed. If plans change such that this issue will be fixed in an upcoming release, then the bug can be reopened.