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

Vitaly Kuznetsov
2020-05-25T15:27:07Z

"Kirill A. Shutemov" <kirill@shutemov.name> writes:

> Wire up hypercalls for the feature and define VM_KVM_PROTECTED.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
> 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