Re: [RFC 10/16] KVM: x86: Enabled protected memory extension

[Vitaly Kuznetsov]

"Kirill A. Shutemov" <kirill@xxxxxxxxxxxxx> writes:

> Wire up hypercalls for the feature and define VM_KVM_PROTECTED.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> ---
>  arch/x86/Kconfig     | 1 +
>  arch/x86/kvm/cpuid.c | 3 +++
>  arch/x86/kvm/x86.c   | 9 +++++++++
>  include/linux/mm.h   | 4 ++++
>  4 files changed, 17 insertions(+)
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 58dd44a1b92f..420e3947f0c6 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -801,6 +801,7 @@ config KVM_GUEST
>  	select ARCH_CPUIDLE_HALTPOLL
>  	select X86_MEM_ENCRYPT_COMMON
>  	select SWIOTLB
> +	select ARCH_USES_HIGH_VMA_FLAGS
>  	default y
>  	---help---
>  	  This option enables various optimizations for running under the KVM
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index 901cd1fdecd9..94cc5e45467e 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -714,6 +714,9 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
>  			     (1 << KVM_FEATURE_POLL_CONTROL) |
>  			     (1 << KVM_FEATURE_PV_SCHED_YIELD);
>  
> +		if (VM_KVM_PROTECTED)
> +			entry->eax |=(1 << KVM_FEATURE_MEM_PROTECTED);

Nit: missing space.

> +
>  		if (sched_info_on())
>  			entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
>  
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index c17e6eb9ad43..acba0ac07f61 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -7598,6 +7598,15 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
>  		kvm_sched_yield(vcpu->kvm, a0);
>  		ret = 0;
>  		break;
> +	case KVM_HC_ENABLE_MEM_PROTECTED:
> +		ret = kvm_protect_all_memory(vcpu->kvm);
> +		break;
> +	case KVM_HC_MEM_SHARE:
> +		ret = kvm_protect_memory(vcpu->kvm, a0, a1, false);
> +		break;
> +	case KVM_HC_MEM_UNSHARE:
> +		ret = kvm_protect_memory(vcpu->kvm, a0, a1, true);
> +		break;
>  	default:
>  		ret = -KVM_ENOSYS;
>  		break;
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 4f7195365cc0..6eb771c14968 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -329,7 +329,11 @@ extern unsigned int kobjsize(const void *objp);
>  # define VM_MAPPED_COPY	VM_ARCH_1	/* T if mapped copy of data (nommu mmap) */
>  #endif
>  
> +#if defined(CONFIG_X86_64) && defined(CONFIG_KVM)
> +#define VM_KVM_PROTECTED VM_HIGH_ARCH_4
> +#else
>  #define VM_KVM_PROTECTED 0
> +#endif
>  
>  #ifndef VM_GROWSUP
>  # define VM_GROWSUP	VM_NONE

-- 
Vitaly