Messages in this thread Patch in this message | | | Subject | Re: [kvmtool PATCH v6 6/6] arm/kvm: arm64: Add a vcpu feature for pointer authentication | From | Amit Daniel Kachhap <> | Date | Fri, 1 Mar 2019 16:07:54 +0530 |
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Hi,
On 2/21/19 9:24 PM, Dave Martin wrote: > On Tue, Feb 19, 2019 at 02:54:31PM +0530, Amit Daniel Kachhap wrote: >> This is a runtime capabality for KVM tool to enable Armv8.3 Pointer >> Authentication in guest kernel. A command line option --ptrauth is >> required for this. >> >> Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com> >> --- >> arm/aarch32/include/kvm/kvm-cpu-arch.h | 1 + >> arm/aarch64/include/asm/kvm.h | 1 + >> arm/aarch64/include/kvm/kvm-config-arch.h | 4 +++- >> arm/aarch64/include/kvm/kvm-cpu-arch.h | 1 + >> arm/include/arm-common/kvm-config-arch.h | 1 + >> arm/kvm-cpu.c | 6 ++++++ >> include/linux/kvm.h | 1 + >> 7 files changed, 14 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..520ea76 100644 >> --- a/arm/aarch32/include/kvm/kvm-cpu-arch.h >> +++ b/arm/aarch32/include/kvm/kvm-cpu-arch.h >> @@ -13,4 +13,5 @@ >> #define ARM_CPU_ID 0, 0, 0 >> #define ARM_CPU_ID_MPIDR 5 >> >> +#define ARM_VCPU_PTRAUTH_FEATURE 0 >> #endif /* KVM__KVM_CPU_ARCH_H */ >> diff --git a/arm/aarch64/include/asm/kvm.h b/arm/aarch64/include/asm/kvm.h >> index 97c3478..1068fd1 100644 >> --- a/arm/aarch64/include/asm/kvm.h >> +++ b/arm/aarch64/include/asm/kvm.h >> @@ -102,6 +102,7 @@ struct kvm_regs { >> #define KVM_ARM_VCPU_EL1_32BIT 1 /* CPU running a 32bit VM */ >> #define KVM_ARM_VCPU_PSCI_0_2 2 /* CPU uses PSCI v0.2 */ >> #define KVM_ARM_VCPU_PMU_V3 3 /* Support guest PMUv3 */ >> +#define KVM_ARM_VCPU_PTRAUTH 4 /* CPU uses pointer authentication */ >> >> struct kvm_vcpu_init { >> __u32 target; >> 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"), > > Nit: doesn't this enable address *and* generic authentication? The > discussion on what capababilities and enables the ABI exposes probably > needs to conclude before we can finalise this here. ok. > > However, I would recommend that we provide a single option here that > turns both address authentication and generic authentication on, even > if the ABI treats them independently. This is expected to be the common > case by far. ok > > We can always add more fine-grained options later if it turns out to be > necessary. Mark suggested to provide 2 flags [1] for Address and Generic authentication so I was thinking of adding 2 features like,
+#define KVM_ARM_VCPU_PTRAUTH_ADDR 4 /* CPU uses pointer address authentication */ +#define KVM_ARM_VCPU_PTRAUTH_GENERIC 5 /* CPU uses pointer generic authentication */
And supply both of them concatenated in VCPU_INIT stage. Kernel KVM would expect both feature requested together.
[1]: https://www.spinics.net/lists/arm-kernel/msg709181.html > >> #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..496ece8 100644 >> --- a/arm/aarch64/include/kvm/kvm-cpu-arch.h >> +++ b/arm/aarch64/include/kvm/kvm-cpu-arch.h >> @@ -17,4 +17,5 @@ >> #define ARM_CPU_CTRL 3, 0, 1, 0 >> #define ARM_CPU_CTRL_SCTLR_EL1 0 >> >> +#define ARM_VCPU_PTRAUTH_FEATURE (1UL << KVM_ARM_VCPU_PTRAUTH) >> #endif /* KVM__KVM_CPU_ARCH_H */ >> diff --git a/arm/include/arm-common/kvm-config-arch.h b/arm/include/arm-common/kvm-config-arch.h >> index 5734c46..5badcbd 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; >> u64 fw_addr; >> }; >> diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c >> index 7780251..4ac80f8 100644 >> --- a/arm/kvm-cpu.c >> +++ b/arm/kvm-cpu.c >> @@ -68,6 +68,12 @@ 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 if available */ >> + if (kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH)) { >> + if (kvm->cfg.arch.has_ptrauth) >> + vcpu_init.features[0] |= ARM_VCPU_PTRAUTH_FEATURE; >> + } >> + > > I'm not too keen on requiring a dummy #define for AArch32 here. How do > we handle other subarch-specific feature flags? Is there something we > can reuse? I will check it.
Thanks, Amit D > > (For SVE I didn''t have a proper solution for this yet: my kvmtool > patches are still a dirty hack...) > > [...] > > Cheers > ---Dave >
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