linux-kernel - [RFC 10/16] KVM: x86: Enabled protected memory extension

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Message-Id: <20200522125214.31348-11-kirill.shutemov@linux.intel.com>
Date:   Fri, 22 May 2020 15:52:08 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>
Cc:     David Rientjes <rientjes@...gle.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Kees Cook <keescook@...omium.org>,
        Will Drewry <wad@...omium.org>,
        "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>,
        "Kleen, Andi" <andi.kleen@...el.com>, x86@...nel.org,
        kvm@...r.kernel.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: [RFC 10/16] KVM: x86: Enabled protected memory extension

Wire up hypercalls for the feature and define VM_KVM_PROTECTED.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.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);
+
 		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
-- 
2.26.2