arm/arm64: KVM: Turn kvm_psci_version into a static inline

We're about to need kvm_psci_version in HYP too. So let's turn it
into a static inline, and pass the kvm structure as a second
parameter (so that HYP can do a kern_hyp_va on it).

Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/kvm/hyp/switch.c

@@ -19,6 +19,8 @@
 #include <linux/jump_label.h>
 #include <uapi/linux/psci.h>
 
+#include <kvm/arm_psci.h>
+
 #include <asm/kvm_asm.h>
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_hyp.h>
@@ -350,14 +352,16 @@ again:
 
 	if (exit_code == ARM_EXCEPTION_TRAP &&
 	    (kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_HVC64 ||
-	     kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_HVC32) &&
-	    vcpu_get_reg(vcpu, 0) == PSCI_0_2_FN_PSCI_VERSION) {
-		u64 val = PSCI_RET_NOT_SUPPORTED;
-		if (test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features))
-			val = 2;
-
-		vcpu_set_reg(vcpu, 0, val);
-		goto again;
+	     kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_HVC32)) {
+		u32 val = vcpu_get_reg(vcpu, 0);
+
+		if (val == PSCI_0_2_FN_PSCI_VERSION) {
+			val = kvm_psci_version(vcpu, kern_hyp_va(vcpu->kvm));
+			if (unlikely(val == KVM_ARM_PSCI_0_1))
+				val = PSCI_RET_NOT_SUPPORTED;
+			vcpu_set_reg(vcpu, 0, val);
+			goto again;
+		}
 	}
 
 	if (static_branch_unlikely(&vgic_v2_cpuif_trap) &&

include/kvm/arm_psci.h

@@ -18,6 +18,7 @@
 #ifndef __KVM_ARM_PSCI_H__
 #define __KVM_ARM_PSCI_H__
 
+#include <linux/kvm_host.h>
 #include <uapi/linux/psci.h>
 
 #define KVM_ARM_PSCI_0_1	PSCI_VERSION(0, 1)
@@ -26,7 +27,25 @@
 
 #define KVM_ARM_PSCI_LATEST	KVM_ARM_PSCI_1_0
 
-int kvm_psci_version(struct kvm_vcpu *vcpu);
+/*
+ * We need the KVM pointer independently from the vcpu as we can call
+ * this from HYP, and need to apply kern_hyp_va on it...
+ */
+static inline int kvm_psci_version(struct kvm_vcpu *vcpu, struct kvm *kvm)
+{
+	/*
+	 * Our PSCI implementation stays the same across versions from
+	 * v0.2 onward, only adding the few mandatory functions (such
+	 * as FEATURES with 1.0) that are required by newer
+	 * revisions. It is thus safe to return the latest.
+	 */
+	if (test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features))
+		return KVM_ARM_PSCI_LATEST;
+
+	return KVM_ARM_PSCI_0_1;
+}
+
+
 int kvm_hvc_call_handler(struct kvm_vcpu *vcpu);
 
 #endif /* __KVM_ARM_PSCI_H__ */

virt/kvm/arm/psci.c

@@ -123,7 +123,7 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
 	if (!vcpu)
 		return PSCI_RET_INVALID_PARAMS;
 	if (!vcpu->arch.power_off) {
-		if (kvm_psci_version(source_vcpu) != KVM_ARM_PSCI_0_1)
+		if (kvm_psci_version(source_vcpu, kvm) != KVM_ARM_PSCI_0_1)
 			return PSCI_RET_ALREADY_ON;
 		else
 			return PSCI_RET_INVALID_PARAMS;
@@ -232,14 +232,6 @@ static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
 	kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET);
 }
 
-int kvm_psci_version(struct kvm_vcpu *vcpu)
-{
-	if (test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features))
-		return KVM_ARM_PSCI_LATEST;
-
-	return KVM_ARM_PSCI_0_1;
-}
-
 static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
 {
 	struct kvm *kvm = vcpu->kvm;
@@ -397,7 +389,7 @@ static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu)
  */
 static int kvm_psci_call(struct kvm_vcpu *vcpu)
 {
-	switch (kvm_psci_version(vcpu)) {
+	switch (kvm_psci_version(vcpu, vcpu->kvm)) {
 	case KVM_ARM_PSCI_1_0:
 		return kvm_psci_1_0_call(vcpu);
 	case KVM_ARM_PSCI_0_2: