KVM: VMX: make MSR bitmaps per-VCPU

Place the MSR bitmap in struct loaded_vmcs, and update it in place
every time the x2apic or APICv state can change.  This is rare and
the loop can handle 64 MSRs per iteration, in a similar fashion as
nested_vmx_prepare_msr_bitmap.

This prepares for choosing, on a per-VM basis, whether to intercept
the SPEC_CTRL and PRED_CMD MSRs.

Cc: [email protected]       # prereq for Spectre mitigation
Suggested-by: Jim Mattson <[email protected]>
Reviewed-by: Konrad Rzeszutek Wilk <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

(cherry-picked from 904e14f)

Orabug: 28069548

Signed-off-by: Mihai Carabas <[email protected]>
Reviewed-by: Darren Kenny <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>
Signed-off-by: Brian Maly <[email protected]>

Conflicts:
	arch/x86/kvm/vmx.c
Contextual - different content. Also vmx_enable_intercept_for_msr was already
in UEK4 as part of commit 8d14695. We just
changed the signature.

Signed-off-by: Brian Maly <[email protected]>

Author: bonzini