This adds sections for KVM API extension for pointer authentication. A brief description about usage of pointer authentication for KVM guests is added in the arm64 documentations. Signed-off-by: Amit Daniel Kachhap <amit.kachhap@xxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Cc: Christoffer Dall <christoffer.dall@xxxxxxx> Cc: Marc Zyngier <marc.zyngier@xxxxxxx> Cc: kvmarm@xxxxxxxxxxxxxxxxxxxxx --- Documentation/arm64/pointer-authentication.txt | 15 +++++++++++---- Documentation/virtual/kvm/api.txt | 6 ++++++ 2 files changed, 17 insertions(+), 4 deletions(-) diff --git a/Documentation/arm64/pointer-authentication.txt b/Documentation/arm64/pointer-authentication.txt index 5baca42..4b769e6 100644 --- a/Documentation/arm64/pointer-authentication.txt +++ b/Documentation/arm64/pointer-authentication.txt @@ -87,7 +87,14 @@ used to get and set the keys for a thread. Virtualization -------------- -Pointer authentication is not currently supported in KVM guests. KVM -will mask the feature bits from ID_AA64ISAR1_EL1, and attempted use of -the feature will result in an UNDEFINED exception being injected into -the guest. +Pointer authentication is enabled in KVM guest when each virtual cpu is +initialised by passing flags KVM_ARM_VCPU_PTRAUTH_[ADDRESS/GENERIC] and +requesting this feature to be enabled. Without this flag, pointer +authentication is not enabled in KVM guests and attempted use of the +feature will result in an UNDEFINED exception being injected into the +guest. + +Additionally, when these vcpu feature flags are not set then KVM will +filter out the Pointer Authentication system key registers from +KVM_GET/SET_REG_* ioctls and mask those features from cpufeature ID +register. diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 7de9eee..b5c66bc 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -2659,6 +2659,12 @@ Possible features: Depends on KVM_CAP_ARM_PSCI_0_2. - KVM_ARM_VCPU_PMU_V3: Emulate PMUv3 for the CPU. Depends on KVM_CAP_ARM_PMU_V3. + - KVM_ARM_VCPU_PTRAUTH_ADDRESS: + - KVM_ARM_VCPU_PTRAUTH_GENERIC: + Enables Pointer authentication for the CPU. + Depends on KVM_CAP_ARM_PTRAUTH and only on arm64 architecture. If + set, then the KVM guest allows the execution of pointer authentication + instructions. Otherwise, KVM treats these instructions as undefined. 4.83 KVM_ARM_PREFERRED_TARGET -- 2.7.4 _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
