[Devel] [PATCH hci-8.0/hci-8.1 5/6] i386: keep v-vmsave-vmload for nested AMD guests on vz types up to vz9.2.0 #VSTOR-152264

[no-reply at sashiko.virtuozzo.com]

> From: Denis V. Lunev <den at openvz.org>
> 
> On Zen 4 client parts (family 19h models 0x18-0x1f and 0x60-0x7f) the
> 6.12 kernel clears virtualized VMSAVE/VMLOAD in init_amd_zen4(), which
> some BIOSes trigger on reboot, and KVM stops offering v-vmsave-vmload.
> A nested guest (svm=on) started before has it in its CPUID, and QEMU
> filters it on such a host, so migration, restore and snapshot revert
> fail.
> 
> Add x-v-vmsave-vmload-compat and turn it on in pc_vz_9_2_compat: an
> AMD guest keeps a requested v-vmsave-vmload. This does not turn host
> VLS back on: KVM keeps intercepting VMLOAD and VMSAVE of the nested
> guest and emulates them (nested_vmcb_needs_vls_intercept()), which is
> only slower.
> 
> Signed-off-by: Denis V. Lunev <den at openvz.org>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.vzint.dev/#/patchset/20261029095645.4173762-1-den@openvz.org?part=5