[v10,1/5] KVM: arm64: Add a vcpu flag to control ptrauth for guest
diff mbox series

Message ID 1555994558-26349-2-git-send-email-amit.kachhap@arm.com
State New, archived
Headers show
Series
  • Add ARMv8.3 pointer authentication for kvm guest
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Commit Message

Amit Daniel Kachhap April 23, 2019, 4:42 a.m. UTC
A per vcpu flag is added to check if pointer authentication is
enabled for the vcpu or not. This flag may be enabled according to
the necessary user policies and host capabilities.

This patch also adds a helper to check the flag.

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
---
Changes since v9:

* Added ptrauth cpufeature static check in vcpu_has_ptrauth [Marc Zyngier].

 arch/arm64/include/asm/kvm_host.h | 5 +++++
 1 file changed, 5 insertions(+)

Comments

Dave Martin April 23, 2019, 3:44 p.m. UTC | #1
On Tue, Apr 23, 2019 at 10:12:34AM +0530, Amit Daniel Kachhap wrote:
> A per vcpu flag is added to check if pointer authentication is
> enabled for the vcpu or not. This flag may be enabled according to
> the necessary user policies and host capabilities.
> 
> This patch also adds a helper to check the flag.
> 
> 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
> ---
> Changes since v9:
> 
> * Added ptrauth cpufeature static check in vcpu_has_ptrauth [Marc Zyngier].
> 
>  arch/arm64/include/asm/kvm_host.h | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 7a096fd..7ccac42 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -355,10 +355,15 @@ struct kvm_vcpu_arch {
>  #define KVM_ARM64_HOST_SVE_ENABLED	(1 << 4) /* SVE enabled for EL0 */
>  #define KVM_ARM64_GUEST_HAS_SVE		(1 << 5) /* SVE exposed to guest */
>  #define KVM_ARM64_VCPU_SVE_FINALIZED	(1 << 6) /* SVE config completed */
> +#define KVM_ARM64_GUEST_HAS_PTRAUTH	(1 << 7) /* PTRAUTH exposed to guest */
>  
>  #define vcpu_has_sve(vcpu) (system_supports_sve() && \
>  			    ((vcpu)->arch.flags & KVM_ARM64_GUEST_HAS_SVE))
>  
> +#define vcpu_has_ptrauth(vcpu)	((system_supports_address_auth() || \
> +				  system_supports_generic_auth()) && \

Come to think of it, should this be
system_supports_address_auth() _&&_ system_supports_generic_auth()?

It won't make a functional difference today though, since today
kvm_vcpu_enable_ptrauth() won't set KVM_ARM64_GUEST_HAS_PTRAUTH without
system_supports_address_auth() and system_supports_generic_auth() both
true.

With || here, we won't have to change this if supporting the two auth
types independently in the future though.

Either way, my Reviewed-by stands.

Cheers
---Dave
Amit Daniel Kachhap April 24, 2019, 5:57 a.m. UTC | #2
Hi,

On 4/23/19 9:14 PM, Dave Martin wrote:
> On Tue, Apr 23, 2019 at 10:12:34AM +0530, Amit Daniel Kachhap wrote:
>> A per vcpu flag is added to check if pointer authentication is
>> enabled for the vcpu or not. This flag may be enabled according to
>> the necessary user policies and host capabilities.
>>
>> This patch also adds a helper to check the flag.
>>
>> 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
>> ---
>> Changes since v9:
>>
>> * Added ptrauth cpufeature static check in vcpu_has_ptrauth [Marc Zyngier].
>>
>>   arch/arm64/include/asm/kvm_host.h | 5 +++++
>>   1 file changed, 5 insertions(+)
>>
>> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
>> index 7a096fd..7ccac42 100644
>> --- a/arch/arm64/include/asm/kvm_host.h
>> +++ b/arch/arm64/include/asm/kvm_host.h
>> @@ -355,10 +355,15 @@ struct kvm_vcpu_arch {
>>   #define KVM_ARM64_HOST_SVE_ENABLED	(1 << 4) /* SVE enabled for EL0 */
>>   #define KVM_ARM64_GUEST_HAS_SVE		(1 << 5) /* SVE exposed to guest */
>>   #define KVM_ARM64_VCPU_SVE_FINALIZED	(1 << 6) /* SVE config completed */
>> +#define KVM_ARM64_GUEST_HAS_PTRAUTH	(1 << 7) /* PTRAUTH exposed to guest */
>>   
>>   #define vcpu_has_sve(vcpu) (system_supports_sve() && \
>>   			    ((vcpu)->arch.flags & KVM_ARM64_GUEST_HAS_SVE))
>>   
>> +#define vcpu_has_ptrauth(vcpu)	((system_supports_address_auth() || \
>> +				  system_supports_generic_auth()) && \
> 
> Come to think of it, should this be
> system_supports_address_auth() _&&_ system_supports_generic_auth()?
I thought about it and kept it this way so that the implementation 
limitation is not introduced in this patch but only in a single place in 
the 3rd patch where all the documentation and reasoning is present on 
doing this way.
> 
> It won't make a functional difference today though, since today
> kvm_vcpu_enable_ptrauth() won't set KVM_ARM64_GUEST_HAS_PTRAUTH without
> system_supports_address_auth() and system_supports_generic_auth() both
> true.
> 
> With || here, we won't have to change this if supporting the two auth
> types independently in the future though.
Yes right.
> 
> Either way, my Reviewed-by stands.
Thanks,
Amit D
> 
> Cheers
> ---Dave
>
Dave Martin April 24, 2019, 1:42 p.m. UTC | #3
On Wed, Apr 24, 2019 at 11:27:50AM +0530, Amit Daniel Kachhap wrote:
> Hi,
> 
> On 4/23/19 9:14 PM, Dave Martin wrote:
> >On Tue, Apr 23, 2019 at 10:12:34AM +0530, Amit Daniel Kachhap wrote:
> >>A per vcpu flag is added to check if pointer authentication is
> >>enabled for the vcpu or not. This flag may be enabled according to
> >>the necessary user policies and host capabilities.
> >>
> >>This patch also adds a helper to check the flag.
> >>
> >>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
> >>---
> >>Changes since v9:
> >>
> >>* Added ptrauth cpufeature static check in vcpu_has_ptrauth [Marc Zyngier].
> >>
> >>  arch/arm64/include/asm/kvm_host.h | 5 +++++
> >>  1 file changed, 5 insertions(+)
> >>
> >>diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> >>index 7a096fd..7ccac42 100644
> >>--- a/arch/arm64/include/asm/kvm_host.h
> >>+++ b/arch/arm64/include/asm/kvm_host.h
> >>@@ -355,10 +355,15 @@ struct kvm_vcpu_arch {
> >>  #define KVM_ARM64_HOST_SVE_ENABLED	(1 << 4) /* SVE enabled for EL0 */
> >>  #define KVM_ARM64_GUEST_HAS_SVE		(1 << 5) /* SVE exposed to guest */
> >>  #define KVM_ARM64_VCPU_SVE_FINALIZED	(1 << 6) /* SVE config completed */
> >>+#define KVM_ARM64_GUEST_HAS_PTRAUTH	(1 << 7) /* PTRAUTH exposed to guest */
> >>  #define vcpu_has_sve(vcpu) (system_supports_sve() && \
> >>  			    ((vcpu)->arch.flags & KVM_ARM64_GUEST_HAS_SVE))
> >>+#define vcpu_has_ptrauth(vcpu)	((system_supports_address_auth() || \
> >>+				  system_supports_generic_auth()) && \
> >
> >Come to think of it, should this be
> >system_supports_address_auth() _&&_ system_supports_generic_auth()?
> I thought about it and kept it this way so that the implementation
> limitation is not introduced in this patch but only in a single place in the
> 3rd patch where all the documentation and reasoning is present on doing this
> way.

OK, I think that's reasonable.  Just wanted to check that I wasn't
missing some subtle issue here.

Cheers
---Dave

Patch
diff mbox series

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 7a096fd..7ccac42 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -355,10 +355,15 @@  struct kvm_vcpu_arch {
 #define KVM_ARM64_HOST_SVE_ENABLED	(1 << 4) /* SVE enabled for EL0 */
 #define KVM_ARM64_GUEST_HAS_SVE		(1 << 5) /* SVE exposed to guest */
 #define KVM_ARM64_VCPU_SVE_FINALIZED	(1 << 6) /* SVE config completed */
+#define KVM_ARM64_GUEST_HAS_PTRAUTH	(1 << 7) /* PTRAUTH exposed to guest */
 
 #define vcpu_has_sve(vcpu) (system_supports_sve() && \
 			    ((vcpu)->arch.flags & KVM_ARM64_GUEST_HAS_SVE))
 
+#define vcpu_has_ptrauth(vcpu)	((system_supports_address_auth() || \
+				  system_supports_generic_auth()) && \
+				 ((vcpu)->arch.flags & KVM_ARM64_GUEST_HAS_PTRAUTH))
+
 #define vcpu_gp_regs(v)		(&(v)->arch.ctxt.gp_regs)
 
 /*