This is a runtime feature and can be enabled by --ptrauth option.

Signed-off-by: Amit Daniel Kachhap <redacted>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Christoffer Dall <redacted>
Cc: Marc Zyngier <redacted>
Cc: Kristina Martsenko <redacted>
Cc: kvmarm@lists.cs.columbia.edu
Cc: Ramana Radhakrishnan <redacted>
Cc: Will Deacon <redacted>
---
 arm/aarch32/include/kvm/kvm-cpu-arch.h    | 2 ++
 arm/aarch64/include/asm/kvm.h             | 3 +++
 arm/aarch64/include/kvm/kvm-arch.h        | 1 +
 arm/aarch64/include/kvm/kvm-config-arch.h | 4 +++-
 arm/aarch64/include/kvm/kvm-cpu-arch.h    | 2 ++
 arm/aarch64/kvm-cpu.c                     | 5 +++++
 arm/include/arm-common/kvm-config-arch.h  | 1 +
 arm/kvm-cpu.c                             | 7 +++++++
 include/linux/kvm.h                       | 1 +
 9 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/arm/aarch32/include/kvm/kvm-cpu-arch.h b/arm/aarch32/include/kvm/kvm-cpu-arch.h
index d28ea67..5779767 100644
--- a/arm/aarch32/include/kvm/kvm-cpu-arch.h
+++ b/arm/aarch32/include/kvm/kvm-cpu-arch.h

@@ -13,4 +13,6 @@
 #define ARM_CPU_ID		0, 0, 0
 #define ARM_CPU_ID_MPIDR	5
 
+unsigned int kvm__cpu_ptrauth_get_feature(void) {}
+

 #endif /* KVM__KVM_CPU_ARCH_H */

diff --git a/arm/aarch64/include/asm/kvm.h b/arm/aarch64/include/asm/kvm.h
index c286035..0fd183d 100644
--- a/arm/aarch64/include/asm/kvm.h
+++ b/arm/aarch64/include/asm/kvm.h

@@ -98,6 +98,9 @@ struct kvm_regs {
 #define KVM_ARM_VCPU_PSCI_0_2		2 /* CPU uses PSCI v0.2 */
 #define KVM_ARM_VCPU_PMU_V3		3 /* Support guest PMUv3 */
 
+/* CPU uses address authentication and A key */
+#define KVM_ARM_VCPU_PTRAUTH		4
+
 struct kvm_vcpu_init {
 	__u32 target;
 	__u32 features[7];

diff --git a/arm/aarch64/include/kvm/kvm-arch.h b/arm/aarch64/include/kvm/kvm-arch.h
index 9de623a..bd566cb 100644
--- a/arm/aarch64/include/kvm/kvm-arch.h
+++ b/arm/aarch64/include/kvm/kvm-arch.h

@@ -11,4 +11,5 @@
 
 #include "arm-common/kvm-arch.h"
 
+
 #endif /* KVM__KVM_ARCH_H */

diff --git a/arm/aarch64/include/kvm/kvm-config-arch.h b/arm/aarch64/include/kvm/kvm-config-arch.h
index 04be43d..2074684 100644
--- a/arm/aarch64/include/kvm/kvm-config-arch.h
+++ b/arm/aarch64/include/kvm/kvm-config-arch.h

@@ -8,7 +8,9 @@
 			"Create PMUv3 device"),				\
 	OPT_U64('\0', "kaslr-seed", &(cfg)->kaslr_seed,			\
 			"Specify random seed for Kernel Address Space "	\
-			"Layout Randomization (KASLR)"),
+			"Layout Randomization (KASLR)"),		\
+	OPT_BOOLEAN('\0', "ptrauth", &(cfg)->has_ptrauth,		\
+			"Enable address authentication"),
 
 #include "arm-common/kvm-config-arch.h"
 

diff --git a/arm/aarch64/include/kvm/kvm-cpu-arch.h b/arm/aarch64/include/kvm/kvm-cpu-arch.h
index a9d8563..f7b64b7 100644
--- a/arm/aarch64/include/kvm/kvm-cpu-arch.h
+++ b/arm/aarch64/include/kvm/kvm-cpu-arch.h

@@ -17,4 +17,6 @@
 #define ARM_CPU_CTRL		3, 0, 1, 0
 #define ARM_CPU_CTRL_SCTLR_EL1	0
 
+unsigned int kvm__cpu_ptrauth_get_feature(void);
+>  #endif /* KVM__KVM_CPU_ARCH_H */

diff --git a/arm/aarch64/kvm-cpu.c b/arm/aarch64/kvm-cpu.c
index 1b29374..10da2cb 100644
--- a/arm/aarch64/kvm-cpu.c
+++ b/arm/aarch64/kvm-cpu.c

@@ -123,6 +123,11 @@ void kvm_cpu__reset_vcpu(struct kvm_cpu *vcpu)
 		return reset_vcpu_aarch64(vcpu);
 }
 
+unsigned int kvm__cpu_ptrauth_get_feature(void)
+{
+	return (1UL << KVM_ARM_VCPU_PTRAUTH);
+}
+