On Mon, Nov 05, 2018 at 02:36:14PM +0000, Marc Zyngier wrote:
> Some implementations may be forced to use VHE to work around HW
> errata, for example. Let's introduce a helper that checks for
> these cases.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
> ---
> arch/arm/include/asm/kvm_host.h | 1 +
> arch/arm64/include/asm/kvm_host.h | 6 ++++++
> virt/kvm/arm/arm.c | 5 +++++
> 3 files changed, 12 insertions(+)
>
> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> index c3469729f40c..0f2f782548cb 100644
> --- a/arch/arm/include/asm/kvm_host.h
> +++ b/arch/arm/include/asm/kvm_host.h
> @@ -286,6 +286,7 @@ void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot);
> struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr);
>
> static inline bool kvm_arch_sve_requires_vhe(void) { return false; }
> +static inline bool kvm_arch_impl_requires_vhe(void) { return false; }
> static inline void kvm_arch_hardware_unsetup(void) {}
> static inline void kvm_arch_sync_events(struct kvm *kvm) {}
> static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index ca1714148400..7d6e974d024a 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -432,6 +432,12 @@ static inline bool kvm_arch_sve_requires_vhe(void)
> return system_supports_sve();
> }
>
> +static inline bool kvm_arch_impl_requires_vhe(void)
> +{
> + /* Some implementations have defects that confine them to VHE */
> + return false;
> +}
> +
> static inline void kvm_arch_hardware_unsetup(void) {}
> static inline void kvm_arch_sync_events(struct kvm *kvm) {}
> static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
> diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> index 66de2efddfca..bc90a1cdd27f 100644
> --- a/virt/kvm/arm/arm.c
> +++ b/virt/kvm/arm/arm.c
> @@ -1647,6 +1647,11 @@ int kvm_arch_init(void *opaque)
> kvm_pr_unimpl("SVE system without VHE unsupported. Broken cpu?");
> return -ENODEV;
> }
> +
> + if (kvm_arch_impl_requires_vhe()) {
> + kvm_pr_unimpl("CPU requiring VHE in non-VHE mode");
( Scratch my previous comment if unless you restructure the code so
there's only one nested if() here. )
Also, minor nit: it sounds like "VHE in non-VHE mode" is the thing this
CPU requires, which is somewhat confusing.
Does it work to word this as
"CPU requiring VHE was booted in non-VHE mode"
?
Cheers
---Dave
