In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Derive GUEST_HAS_SVE from the SVE feature bit at EL2 pkvm_

In the Linux kernel, the following vulnerability has been resolved:

KVM: arm64: Derive GUEST_HAS_SVE from the SVE feature bit at EL2

pkvm_init_features_from_host() takes KVM_ARCH_FLAG_GUEST_HAS_SVE and
KVM_ARM_VCPU_SVE from the host separately, but pkvm_vcpu_init_sve()
tests the bit while vcpu_has_sve() reads the flag. A host that sets the
flag without the bit gets a vCPU with a NULL sve_state that the world
switch loads the guest's SVE state from.

Derive the flag from the bit, and drop the protected path's copy of the
host's flag, which is dead code since protected VMs are not allowed SVE.