Merge branch 'kvm-arm64/ptrauth-nvhe' into kvmarm-master/next-WIP

Signed-off-by: Marc Zyngier <maz@kernel.org>

arch/arm64/Kconfig

@@ -1516,7 +1516,6 @@ menu "ARMv8.3 architectural features"
 config ARM64_PTR_AUTH
 	bool "Enable support for pointer authentication"
 	default y
-	depends on !KVM || ARM64_VHE
 	depends on (CC_HAS_SIGN_RETURN_ADDRESS || CC_HAS_BRANCH_PROT_PAC_RET) && AS_HAS_PAC
 	# Modern compilers insert a .note.gnu.property section note for PAC
 	# which is only understood by binutils starting with version 2.33.1.
@@ -1543,8 +1542,7 @@ config ARM64_PTR_AUTH
 
 	  The feature is detected at runtime. If the feature is not present in
 	  hardware it will not be advertised to userspace/KVM guest nor will it
-	  be enabled. However, KVM guest also require VHE mode and hence
-	  CONFIG_ARM64_VHE=y option to use this feature.
+	  be enabled.
 
 	  If the feature is present on the boot CPU but not on a late CPU, then
 	  the late CPU will be parked. Also, if the boot CPU does not have

arch/arm64/include/asm/kvm_ptrauth.h

@@ -61,44 +61,36 @@
 
 /*
  * Both ptrauth_switch_to_guest and ptrauth_switch_to_host macros will
- * check for the presence of one of the cpufeature flag
- * ARM64_HAS_ADDRESS_AUTH_ARCH or ARM64_HAS_ADDRESS_AUTH_IMP_DEF and
+ * check for the presence ARM64_HAS_ADDRESS_AUTH, which is defined as
+ * (ARM64_HAS_ADDRESS_AUTH_ARCH || ARM64_HAS_ADDRESS_AUTH_IMP_DEF) and
  * then proceed ahead with the save/restore of Pointer Authentication
- * key registers.
+ * key registers if enabled for the guest.
  */
 .macro ptrauth_switch_to_guest g_ctxt, reg1, reg2, reg3
-alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH
-	b	1000f
+alternative_if_not ARM64_HAS_ADDRESS_AUTH
+	b	.L__skip_switch\@
 alternative_else_nop_endif
-alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF
-	b	1001f
-alternative_else_nop_endif
-1000:
-	ldr	\reg1, [\g_ctxt, #(VCPU_HCR_EL2 - VCPU_CONTEXT)]
+	mrs	\reg1, hcr_el2
 	and	\reg1, \reg1, #(HCR_API | HCR_APK)
-	cbz	\reg1, 1001f
+	cbz	\reg1, .L__skip_switch\@
 	add	\reg1, \g_ctxt, #CPU_APIAKEYLO_EL1
 	ptrauth_restore_state	\reg1, \reg2, \reg3
-1001:
+.L__skip_switch\@:
 .endm
 
 .macro ptrauth_switch_to_host g_ctxt, h_ctxt, reg1, reg2, reg3
-alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH
-	b	2000f
-alternative_else_nop_endif
-alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF
-	b	2001f
+alternative_if_not ARM64_HAS_ADDRESS_AUTH
+	b	.L__skip_switch\@
 alternative_else_nop_endif
-2000:
-	ldr	\reg1, [\g_ctxt, #(VCPU_HCR_EL2 - VCPU_CONTEXT)]
+	mrs	\reg1, hcr_el2
 	and	\reg1, \reg1, #(HCR_API | HCR_APK)
-	cbz	\reg1, 2001f
+	cbz	\reg1, .L__skip_switch\@
 	add	\reg1, \g_ctxt, #CPU_APIAKEYLO_EL1
 	ptrauth_save_state	\reg1, \reg2, \reg3
 	add	\reg1, \h_ctxt, #CPU_APIAKEYLO_EL1
 	ptrauth_restore_state	\reg1, \reg2, \reg3
 	isb
-2001:
+.L__skip_switch\@:
 .endm
 
 #else /* !CONFIG_ARM64_PTR_AUTH */

arch/arm64/kvm/hyp/nvhe/hyp-init.S

@@ -104,6 +104,11 @@ alternative_else_nop_endif
 	 */
 	mov_q	x4, (SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A))
 CPU_BE(	orr	x4, x4, #SCTLR_ELx_EE)
+alternative_if ARM64_HAS_ADDRESS_AUTH
+	mov_q	x5, (SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | \
+		     SCTLR_ELx_ENDA | SCTLR_ELx_ENDB)
+	orr	x4, x4, x5
+alternative_else_nop_endif
 	msr	sctlr_el2, x4
 	isb
 

arch/arm64/kvm/reset.c

@@ -42,6 +42,11 @@ static u32 kvm_ipa_limit;
 #define VCPU_RESET_PSTATE_SVC	(PSR_AA32_MODE_SVC | PSR_AA32_A_BIT | \
 				 PSR_AA32_I_BIT | PSR_AA32_F_BIT)
 
+static bool system_has_full_ptr_auth(void)
+{
+	return system_supports_address_auth() && system_supports_generic_auth();
+}
+
 /**
  * kvm_arch_vm_ioctl_check_extension
  *
@@ -80,8 +85,7 @@ int kvm_arch_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 		break;
 	case KVM_CAP_ARM_PTRAUTH_ADDRESS:
 	case KVM_CAP_ARM_PTRAUTH_GENERIC:
-		r = has_vhe() && system_supports_address_auth() &&
-				 system_supports_generic_auth();
+		r = system_has_full_ptr_auth();
 		break;
 	default:
 		r = 0;
@@ -205,19 +209,14 @@ static void kvm_vcpu_reset_sve(struct kvm_vcpu *vcpu)
 
 static int kvm_vcpu_enable_ptrauth(struct kvm_vcpu *vcpu)
 {
-	/* Support ptrauth only if the system supports these capabilities. */
-	if (!has_vhe())
-		return -EINVAL;
-
-	if (!system_supports_address_auth() ||
-	    !system_supports_generic_auth())
-		return -EINVAL;
 	/*
 	 * For now make sure that both address/generic pointer authentication
-	 * features are requested by the userspace together.
+	 * features are requested by the userspace together and the system
+	 * supports these capabilities.
 	 */
 	if (!test_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, vcpu->arch.features) ||
-	    !test_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, vcpu->arch.features))
+	    !test_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, vcpu->arch.features) ||
+	    !system_has_full_ptr_auth())
 		return -EINVAL;
 
 	vcpu->arch.flags |= KVM_ARM64_GUEST_HAS_PTRAUTH;