KVM: PPC: Book3S HV: Add function kvmhv_vcpu_is_radix()

There exists a function kvm_is_radix() which is used to determine if a
kvm instance is using the radix mmu. However this only applies to the
first level (L1) guest. Add a function kvmhv_vcpu_is_radix() which can
be used to determine if the current execution context of the vcpu is
radix, accounting for if the vcpu is running a nested guest.

Currently all nested guests must be radix but this may change in the
future.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

arch/powerpc/include/asm/kvm_book3s_64.h

@@ -55,6 +55,7 @@ struct kvm_nested_guest {
 	cpumask_t need_tlb_flush;
 	cpumask_t cpu_in_guest;
 	short prev_cpu[NR_CPUS];
+	u8 radix;			/* is this nested guest radix */
 };
 
 /*
@@ -150,6 +151,18 @@ static inline bool kvm_is_radix(struct kvm *kvm)
 	return kvm->arch.radix;
 }
 
+static inline bool kvmhv_vcpu_is_radix(struct kvm_vcpu *vcpu)
+{
+	bool radix;
+
+	if (vcpu->arch.nested)
+		radix = vcpu->arch.nested->radix;
+	else
+		radix = kvm_is_radix(vcpu->kvm);
+
+	return radix;
+}
+
 #define KVM_DEFAULT_HPT_ORDER	24	/* 16MB HPT by default */
 #endif
 

arch/powerpc/kvm/book3s_hv_nested.c

@@ -480,6 +480,7 @@ struct kvm_nested_guest *kvmhv_alloc_nested(struct kvm *kvm, unsigned int lpid)
 	if (shadow_lpid < 0)
 		goto out_free2;
 	gp->shadow_lpid = shadow_lpid;
+	gp->radix = 1;
 
 	memset(gp->prev_cpu, -1, sizeof(gp->prev_cpu));