[PATCH v2 8/8] arm64: kvm: Check support for AArch32 for 32bit guests
From: Marc Zyngier <hidden>
Date: 2016-03-02 09:08:21
Also in:
kvmarm, lkml
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 <redacted>
Cc: Marc Zyngier <redacted>
Cc: kvmarm at 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.
quoted hunk ↗ jump to hunk
--- 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. -- Jazz is not dead. It just smells funny...