| Message ID | 1456393968-17386-9-git-send-email-suzuki.poulose@arm.com |
|---|---|
| State | New |
| Headers | show |
On 25/02/16 09:52, Suzuki K Poulose wrote: > Add a check to make sure the system supports AArch32 state > before initialising a 32bit guest. > > Cc: Christoffer Dall <christoffer.dall@linaro.org> > Cc: Marc Zyngier <marc.zyngier@arm.com> > Cc: kvmarm@lists.cs.columbia.edu > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> > > --- > > I really wanted to pass kvm_vcpu down to the helpers. But then, I can't > define the arch specific helper in asm/kvm_host.h due to lack of kvm_vcpu's > definition yet: > > In file included from include/linux/kvm_host.h:35:0, > from arch/arm64/kernel/asm-offsets.c:24: > ./arch/arm64/include/asm/kvm_host.h: In function ‘kvm_arch_vcpu_validate_features’: > ./arch/arm64/include/asm/kvm_host.h:344:48: error: dereferencing pointer to incomplete type > return !test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features) || Why don't you just have the prototype in kvm_host.h, and move the actual implementation to something like guest.c? But I think there is a better approach, see below. > --- > arch/arm/include/asm/kvm_host.h | 5 +++++ > arch/arm/kvm/arm.c | 3 +++ > arch/arm64/include/asm/kvm_host.h | 8 ++++++++ > 3 files changed, 16 insertions(+) > > diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h > index f9f2779..945c23a 100644 > --- a/arch/arm/include/asm/kvm_host.h > +++ b/arch/arm/include/asm/kvm_host.h > @@ -238,6 +238,11 @@ static inline void kvm_arch_sync_events(struct kvm *kvm) {} > static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} > static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} > > +static inline bool kvm_arch_vcpu_validate_features(struct kvm_vcpu_arch *arch_vcpu) > +{ > + return true; > +} > + > static inline void kvm_arm_init_debug(void) {} > static inline void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) {} > static inline void kvm_arm_clear_debug(struct kvm_vcpu *vcpu) {} > diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c > index dda1959..fc4ea37 100644 > --- a/arch/arm/kvm/arm.c > +++ b/arch/arm/kvm/arm.c > @@ -787,6 +787,9 @@ static int kvm_vcpu_set_target(struct kvm_vcpu *vcpu, > set_bit(i, vcpu->arch.features); > } > > + if (!kvm_arch_vcpu_validate_features(&vcpu->arch)) > + return -EINVAL; > + > vcpu->arch.target = phys_target; > > /* Now we know what it is, we can reset it. */ > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 689d4c9..9d60a6c 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -24,6 +24,8 @@ > > #include <linux/types.h> > #include <linux/kvm_types.h> > +#include <asm/cpufeature.h> > +#include <asm/kvm_arm.h> > #include <asm/kvm.h> > #include <asm/kvm_mmio.h> > > @@ -338,6 +340,12 @@ static inline void kvm_arch_sync_events(struct kvm *kvm) {} > static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} > static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} > > +static inline bool kvm_arch_vcpu_validate_features(struct kvm_vcpu_arch *arch_vcpu) > +{ > + return !test_bit(KVM_ARM_VCPU_EL1_32BIT, arch_vcpu->features) || > + system_supports_32bit_el0(); > +} > + This is really convoluted (it took me 5 minutes staring at the expression and remembering that AArch32 EL1 implies AArch32 EL0 to get it). Now, we already have kvm_reset_vcpu() that validates AArch32 support. It would probably be better to move things there. Thoughts? > void kvm_arm_init_debug(void); > void kvm_arm_setup_debug(struct kvm_vcpu *vcpu); > void kvm_arm_clear_debug(struct kvm_vcpu *vcpu); > Thanks, M.
On 02/03/16 09:08, Marc Zyngier wrote: > On 25/02/16 09:52, Suzuki K Poulose wrote: >> I really wanted to pass kvm_vcpu down to the helpers. But then, I can't >> define the arch specific helper in asm/kvm_host.h due to lack of kvm_vcpu's >> definition yet: >> >> In file included from include/linux/kvm_host.h:35:0, >> from arch/arm64/kernel/asm-offsets.c:24: >> ./arch/arm64/include/asm/kvm_host.h: In function ‘kvm_arch_vcpu_validate_features’: >> ./arch/arm64/include/asm/kvm_host.h:344:48: error: dereferencing pointer to incomplete type >> return !test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features) || > > Why don't you just have the prototype in kvm_host.h, and move the actual > implementation to something like guest.c? But I think there is a better > approach, see below. I thought it would better be a static inline. But, the GCC can do that, silly me :) > > This is really convoluted (it took me 5 minutes staring at the > expression and remembering that AArch32 EL1 implies AArch32 EL0 to get it). > > Now, we already have kvm_reset_vcpu() that validates AArch32 support. It > would probably be better to move things there. Thoughts? Definitely. I overlooked the function name to do something specific to resetting the CPU than doing some checks :(. I will respin it. Cheers Suzuki
On 02/03/16 09:08, Marc Zyngier wrote: > On 25/02/16 09:52, Suzuki K Poulose wrote: >> Add a check to make sure the system supports AArch32 state >> before initialising a 32bit guest. >> >> Cc: Christoffer Dall <christoffer.dall@linaro.org> >> Cc: Marc Zyngier <marc.zyngier@arm.com> >> Cc: kvmarm@lists.cs.columbia.edu >> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> ... >> @@ -338,6 +340,12 @@ static inline void kvm_arch_sync_events(struct kvm *kvm) {} >> static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} >> static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} >> >> +static inline bool kvm_arch_vcpu_validate_features(struct kvm_vcpu_arch *arch_vcpu) >> +{ >> + return !test_bit(KVM_ARM_VCPU_EL1_32BIT, arch_vcpu->features) || >> + system_supports_32bit_el0(); >> +} >> + > > This is really convoluted (it took me 5 minutes staring at the > expression and remembering that AArch32 EL1 implies AArch32 EL0 to get it). > > Now, we already have kvm_reset_vcpu() that validates AArch32 support. It > would probably be better to move things there. Thoughts? I think we can leave the kvm bits as it is now, discarding this patch, as we already do the right thing. Also system_supports_32bit_el0() doesn't guarantee system_supports_32bit_el1(). The negation and converse are both true though. i.e, !32bit_el0_support => !32bit_el1_support & 32bit_el1_support => 32bit_el0_support Thanks Suzuki
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index f9f2779..945c23a 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -238,6 +238,11 @@ static inline void kvm_arch_sync_events(struct kvm *kvm) {} static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} +static inline bool kvm_arch_vcpu_validate_features(struct kvm_vcpu_arch *arch_vcpu) +{ + return true; +} + static inline void kvm_arm_init_debug(void) {} static inline void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) {} static inline void kvm_arm_clear_debug(struct kvm_vcpu *vcpu) {} diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index dda1959..fc4ea37 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -787,6 +787,9 @@ static int kvm_vcpu_set_target(struct kvm_vcpu *vcpu, set_bit(i, vcpu->arch.features); } + if (!kvm_arch_vcpu_validate_features(&vcpu->arch)) + return -EINVAL; + vcpu->arch.target = phys_target; /* Now we know what it is, we can reset it. */ diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 689d4c9..9d60a6c 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -24,6 +24,8 @@ #include <linux/types.h> #include <linux/kvm_types.h> +#include <asm/cpufeature.h> +#include <asm/kvm_arm.h> #include <asm/kvm.h> #include <asm/kvm_mmio.h> @@ -338,6 +340,12 @@ static inline void kvm_arch_sync_events(struct kvm *kvm) {} static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} +static inline bool kvm_arch_vcpu_validate_features(struct kvm_vcpu_arch *arch_vcpu) +{ + return !test_bit(KVM_ARM_VCPU_EL1_32BIT, arch_vcpu->features) || + system_supports_32bit_el0(); +} + void kvm_arm_init_debug(void); void kvm_arm_setup_debug(struct kvm_vcpu *vcpu); void kvm_arm_clear_debug(struct kvm_vcpu *vcpu);
Add a check to make sure the system supports AArch32 state before initialising a 32bit guest. Cc: Christoffer Dall <christoffer.dall@linaro.org> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: kvmarm@lists.cs.columbia.edu Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> --- I really wanted to pass kvm_vcpu down to the helpers. But then, I can't define the arch specific helper in asm/kvm_host.h due to lack of kvm_vcpu's definition yet: In file included from include/linux/kvm_host.h:35:0, from arch/arm64/kernel/asm-offsets.c:24: ./arch/arm64/include/asm/kvm_host.h: In function ‘kvm_arch_vcpu_validate_features’: ./arch/arm64/include/asm/kvm_host.h:344:48: error: dereferencing pointer to incomplete type return !test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features) || --- arch/arm/include/asm/kvm_host.h | 5 +++++ arch/arm/kvm/arm.c | 3 +++ arch/arm64/include/asm/kvm_host.h | 8 ++++++++ 3 files changed, 16 insertions(+)