KVM: x86: Calculate the supported xcr0 mask at load time

Add a new global variable, supported_xcr0, to track which xcr0 bits can
be exposed to the guest instead of calculating the mask on every call.
The supported bits are constant for a given instance of KVM.

This paves the way toward eliminating the ->mpx_supported() call in
kvm_mpx_supported(), e.g. eliminates multiple retpolines in VMX's nested
VM-Enter path, and eventually toward eliminating ->mpx_supported()
altogether.

No functional change intended.

Reviewed-by: Xiaoyao Li <[email protected]>
Reviewed-by: Vitaly Kuznetsov <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

0 files changed, 0 insertions, 0 deletions