This improves compatibility for guests w.r.t. live-migration, or live
snapshot rollback, to hosts with less (FPU) xfeatures supported, as
long as the set of features that was actually exposed to the guest is
still supported.
This improves on the ad856280ddea ("x86/kvm/fpu: Limit guest
user_xfeatures to supported bits of XCR0") bug fix.
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
