KVM: arm64: nv: Hoist vcpu_has_nv() into is_hyp_ctxt()

A rather common idiom when writing NV code as part of KVM is
to have things such has:

	if (vcpu_has_nv(vcpu) && is_hyp_ctxt(vcpu)) {
		[...]
	}

to check that we are in a hyp-related context. The second part of
the conjunction would be enough, but the first one contains a
static key that allows the rest of the checkis to be elided when
in a non-NV environment.

Rewrite is_hyp_ctxt() to directly use vcpu_has_nv(). The result
is the same, and the code easier to read. The one occurence of
this that is already merged is rewritten in the process.

In order to avoid nasty cirtular dependencies between kvm_emulate.h
and kvm_nested.h, vcpu_has_feature() is itself hoisted into kvm_host.h,
at the cost of some #deferry...
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>

arch/arm64/include/asm/kvm_emulate.h

@@ -17,6 +17,7 @@
 #include <asm/esr.h>
 #include <asm/kvm_arm.h>
 #include <asm/kvm_hyp.h>
+#include <asm/kvm_nested.h>
 #include <asm/ptrace.h>
 #include <asm/cputype.h>
 #include <asm/virt.h>
@@ -54,11 +55,6 @@ void kvm_emulate_nested_eret(struct kvm_vcpu *vcpu);
 int kvm_inject_nested_sync(struct kvm_vcpu *vcpu, u64 esr_el2);
 int kvm_inject_nested_irq(struct kvm_vcpu *vcpu);
 
-static inline bool vcpu_has_feature(const struct kvm_vcpu *vcpu, int feature)
-{
-	return test_bit(feature, vcpu->kvm->arch.vcpu_features);
-}
-
 #if defined(__KVM_VHE_HYPERVISOR__) || defined(__KVM_NVHE_HYPERVISOR__)
 static __always_inline bool vcpu_el1_is_32bit(struct kvm_vcpu *vcpu)
 {
@@ -248,7 +244,7 @@ static inline bool __is_hyp_ctxt(const struct kvm_cpu_context *ctxt)
 
 static inline bool is_hyp_ctxt(const struct kvm_vcpu *vcpu)
 {
-	return __is_hyp_ctxt(&vcpu->arch.ctxt);
+	return vcpu_has_nv(vcpu) && __is_hyp_ctxt(&vcpu->arch.ctxt);
 }
 
 /*

arch/arm64/include/asm/kvm_host.h

@@ -1177,6 +1177,13 @@ bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu);
 #define kvm_vm_has_ran_once(kvm)					\
 	(test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &(kvm)->arch.flags))
 
+static inline bool __vcpu_has_feature(const struct kvm_arch *ka, int feature)
+{
+	return test_bit(feature, ka->vcpu_features);
+}
+
+#define vcpu_has_feature(v, f)	__vcpu_has_feature(&(v)->kvm->arch, (f))
+
 int kvm_trng_call(struct kvm_vcpu *vcpu);
 #ifdef CONFIG_KVM
 extern phys_addr_t hyp_mem_base;

arch/arm64/kvm/arch_timer.c

@@ -295,8 +295,7 @@ static u64 wfit_delay_ns(struct kvm_vcpu *vcpu)
 	u64 val = vcpu_get_reg(vcpu, kvm_vcpu_sys_get_rt(vcpu));
 	struct arch_timer_context *ctx;
 
-	ctx = (vcpu_has_nv(vcpu) && is_hyp_ctxt(vcpu)) ? vcpu_hvtimer(vcpu)
-						       : vcpu_vtimer(vcpu);
+	ctx = is_hyp_ctxt(vcpu) ? vcpu_hvtimer(vcpu) : vcpu_vtimer(vcpu);
 
 	return kvm_counter_compute_delta(ctx, val);
 }