diff options
| author | Amit Daniel Kachhap <amit.kachhap@arm.com> | 2019-04-23 10:12:36 +0530 |
|---|---|---|
| committer | Marc Zyngier <marc.zyngier@arm.com> | 2019-04-24 15:30:40 +0100 |
| commit | a22fa321d13b0264976cbbc1d22f4c27c41d3642 (patch) | |
| tree | 1f68397998eccf792fa7452d89a00ed6e6350488 /Documentation | |
| parent | 384b40caa8afae44a54e8f69bd37097c0279fdce (diff) | |
KVM: arm64: Add userspace flag to enable pointer authentication
Now that the building blocks of pointer authentication are present, lets
add userspace flags KVM_ARM_VCPU_PTRAUTH_ADDRESS and
KVM_ARM_VCPU_PTRAUTH_GENERIC. These flags will enable pointer
authentication for the KVM guest on a per-vcpu basis through the ioctl
KVM_ARM_VCPU_INIT.
This features will allow the KVM guest to allow the handling of
pointer authentication instructions or to treat them as undefined
if not set.
Necessary documentations are added to reflect the changes done.
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Christoffer Dall <christoffer.dall@arm.com>
Cc: kvmarm@lists.cs.columbia.edu
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/arm64/pointer-authentication.txt | 22 | ||||
| -rw-r--r-- | Documentation/virtual/kvm/api.txt | 10 |
2 files changed, 28 insertions, 4 deletions
diff --git a/Documentation/arm64/pointer-authentication.txt b/Documentation/arm64/pointer-authentication.txt index 5baca42ba146..fc71b33de87e 100644 --- a/Documentation/arm64/pointer-authentication.txt +++ b/Documentation/arm64/pointer-authentication.txt @@ -87,7 +87,21 @@ 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 these two separate cpu features to be enabled. The current KVM +guest implementation works by enabling both features together, so both +these userspace flags are checked before enabling pointer authentication. +The separate userspace flag will allow to have no userspace ABI changes +if support is added in the future to allow these two features to be +enabled independently of one another. + +As Arm Architecture specifies that Pointer Authentication feature is +implemented along with the VHE feature so KVM arm64 ptrauth code relies +on VHE mode to be present. + +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. Any attempt to use the Pointer Authentication instructions will +result in an UNDEFINED exception being injected into the guest. diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index e410a9f0f0d4..32afe7f5c35a 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -2761,6 +2761,16 @@ Possible features: - KVM_ARM_VCPU_PMU_V3: Emulate PMUv3 for the CPU. Depends on KVM_CAP_ARM_PMU_V3. + - KVM_ARM_VCPU_PTRAUTH_ADDRESS: Enables Address Pointer authentication + for arm64 only. + Both KVM_ARM_VCPU_PTRAUTH_ADDRESS and KVM_ARM_VCPU_PTRAUTH_GENERIC + must be requested or neither must be requested. + + - KVM_ARM_VCPU_PTRAUTH_GENERIC: Enables Generic Pointer authentication + for arm64 only. + Both KVM_ARM_VCPU_PTRAUTH_ADDRESS and KVM_ARM_VCPU_PTRAUTH_GENERIC + must be requested or neither must be requested. + - KVM_ARM_VCPU_SVE: Enables SVE for the CPU (arm64 only). Depends on KVM_CAP_ARM_SVE. Requires KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): |