Hi Dave,
On 3/1/19 4:54 PM, Dave P Martin wrote:
On Fri, Mar 01, 2019 at 10:37:54AM +0000, Amit Daniel Kachhap wrote:
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:
[...]
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.
Seems reasonable. Do you mean the kernel would treat it as an error if
only one of these flags is passed to KVM_ARM_VCPU_INIT, or would KVM
simply treat them as independent?
If both flags are passed together then only start using ptrauth
otherwise keep ptrauth disabled. This is just to finalize the user side
abi as of now and KVM can be updated later.
Thanks,
Amit D
[...]
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.
OK
Cheers
---Dave
_______________________________________________
kvmarm mailing list
kvmarm@xxxxxxxxxxxxxxxxxxxxx
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
