KVM: arm64: Add helper to identify a nested context

A common idiom in the KVM code is to check if we are currently
dealing with a "nested" context, defined as having NV enabled,
but being in the EL1&0 translation regime.

This is usually expressed as:

	if (vcpu_has_nv(vcpu) && !is_hyp_ctxt(vcpu) ... )

which is a mouthful and a bit hard to read, specially when followed
by additional conditions.

Introduce a new helper that encapsulate these two terms, allowing
the above to be written as

	if (is_nested_context(vcpu) ... )

which is both shorter and easier to read, and makes more obvious
the potential for simplification on some code paths.

Signed-off-by: Marc Zyngier <[email protected]>
Reviewed-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Oliver Upton <[email protected]>

1 files changed, 2 insertions, 7 deletions

diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c
index 3a384e9660b8..1de4a9001d9d 100644
--- a/arch/arm64/kvm/emulate-nested.c
+++ b/arch/arm64/kvm/emulate-nested.c
@@ -2592,13 +2592,8 @@ inject:
 
 static bool __forward_traps(struct kvm_vcpu *vcpu, unsigned int reg, u64 control_bit)
 {
-	bool control_bit_set;
-
-	if (!vcpu_has_nv(vcpu))
-		return false;
-
-	control_bit_set = __vcpu_sys_reg(vcpu, reg) & control_bit;
-	if (!is_hyp_ctxt(vcpu) && control_bit_set) {
+	if (is_nested_ctxt(vcpu) &&
+	    (__vcpu_sys_reg(vcpu, reg) & control_bit)) {
 		kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu));
 		return true;
 	}