[kvmtool PATCH v5 6/6] arm/kvm: arm64: Add a vcpu feature for pointer authentication

Amit Daniel Kachhap
2019-01-28T06:58:47Z

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

Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Christoffer Dall <christoffer.dall@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Kristina Martsenko <kristina.martsenko@arm.com>
Cc: kvmarm@lists.cs.columbia.edu
Cc: Ramana Radhakrishnan <ramana.radhakrishnan@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
---
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);
+}
+
int kvm_cpu__get_endianness(struct kvm_cpu *vcpu)
{
struct kvm_one_reg reg;
diff --git a/arm/include/arm-common/kvm-config-arch.h b/arm/include/arm-common/kvm-config-arch.h
index 6a196f1..eb872db 100644
--- a/arm/include/arm-common/kvm-config-arch.h
+++ b/arm/include/arm-common/kvm-config-arch.h
@@ -10,6 +10,7 @@ struct kvm_config_arch {
bool aarch32_guest;
bool has_pmuv3;
u64 kaslr_seed;
+ bool has_ptrauth;
enum irqchip_type irqchip;
};

diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
index 7780251..5afd727 100644
--- a/arm/kvm-cpu.c
+++ b/arm/kvm-cpu.c
@@ -68,6 +68,13 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id)
vcpu_init.features[0] |= (1UL << KVM_ARM_VCPU_PSCI_0_2);
}

+ /* Set KVM_ARM_VCPU_PTRAUTH_I_A if available */
+ if (kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH)) {
+ if (kvm->cfg.arch.has_ptrauth)
+ vcpu_init.features[0] |=
+ kvm__cpu_ptrauth_get_feature();
+ }
+
/*
* If the preferred target ioctl is successful then
* use preferred target else try each and every target type
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index f51d508..204315e 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -883,6 +883,7 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_PPC_MMU_RADIX 134
#define KVM_CAP_PPC_MMU_HASH_V3 135
#define KVM_CAP_IMMEDIATE_EXIT 136
+#define KVM_CAP_ARM_PTRAUTH 168

#ifdef KVM_CAP_IRQ_ROUTING

--
2.7.4