[PATCH v3 11/15] KVM: arm64: nv: Add kvm_has_pauth() helper

Marc Zyngier
2024-03-21T15:54:33Z

Pointer Authentication comes in many flavors, and a faithful emulation
relies on correctly handling the flavour implemented by the HW.

For this, provide a new kvm_has_pauth() that checks whether we
expose to the guest a particular level of support. This checks
across all 3 possible authentication algorithms (Q5, Q3 and IMPDEF).

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/include/asm/kvm_host.h | 15 +++++++++++++++
1 file changed, 15 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 3f1c3c91e5c2..a65701b95078 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -1335,4 +1335,19 @@ bool kvm_arm_vcpu_stopped(struct kvm_vcpu *vcpu);
(get_idreg_field((kvm), id, fld) >= expand_field_sign(id, fld, min) && \
get_idreg_field((kvm), id, fld) <= expand_field_sign(id, fld, max))

+/* Check for a given level of PAuth support */
+#define kvm_has_pauth(k, l) \
+ ({ \
+ bool pa, pi, pa3; \
+ \
+ pa = kvm_has_feat((k), ID_AA64ISAR1_EL1, APA, l); \
+ pa &= kvm_has_feat((k), ID_AA64ISAR1_EL1, GPA, IMP); \
+ pi = kvm_has_feat((k), ID_AA64ISAR1_EL1, API, l); \
+ pi &= kvm_has_feat((k), ID_AA64ISAR1_EL1, GPI, IMP); \
+ pa3 = kvm_has_feat((k), ID_AA64ISAR2_EL1, APA3, l); \
+ pa3 &= kvm_has_feat((k), ID_AA64ISAR2_EL1, GPA3, IMP); \
+ \
+ (pa + pi + pa3) == 1; \
+ })
+
#endif /* __ARM64_KVM_HOST_H__ */
--
2.39.2