linux-kernel - [PATCH v2 9/9] KVM: VMX: drop ept misconfig check

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Message-Id: <1438747467-25425-10-git-send-email-guangrong.xiao@linux.intel.com>
Date:	Wed,  5 Aug 2015 12:04:27 +0800
From:	Xiao Guangrong <guangrong.xiao@...ux.intel.com>
To:	pbonzini@...hat.com
Cc:	gleb@...nel.org, mtosatti@...hat.com, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org, ru.pchel@...il.com,
	Xiao Guangrong <guangrong.xiao@...ux.intel.com>
Subject: [PATCH v2 9/9] KVM: VMX: drop ept misconfig check

The logic used to check ept misconfig is completely contained in common
reserved bits check for sptes, so it can be removed

Signed-off-by: Xiao Guangrong <guangrong.xiao@...ux.intel.com>
---
 arch/x86/kvm/mmu.c | 22 ----------------
 arch/x86/kvm/mmu.h |  1 -
 arch/x86/kvm/vmx.c | 74 ++----------------------------------------------------
 3 files changed, 2 insertions(+), 95 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 1393317..1dabaec 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -4937,28 +4937,6 @@ unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
 	return nr_mmu_pages;
 }
 
-int kvm_mmu_get_spte_hierarchy(struct kvm_vcpu *vcpu, u64 addr, u64 sptes[4])
-{
-	struct kvm_shadow_walk_iterator iterator;
-	u64 spte;
-	int nr_sptes = 0;
-
-	if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
-		return nr_sptes;
-
-	walk_shadow_page_lockless_begin(vcpu);
-	for_each_shadow_entry_lockless(vcpu, addr, iterator, spte) {
-		sptes[iterator.level-1] = spte;
-		nr_sptes++;
-		if (!is_shadow_present_pte(spte))
-			break;
-	}
-	walk_shadow_page_lockless_end(vcpu);
-
-	return nr_sptes;
-}
-EXPORT_SYMBOL_GPL(kvm_mmu_get_spte_hierarchy);
-
 void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
 {
 	kvm_mmu_unload(vcpu);
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 2299d15..e4202e4 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -50,7 +50,6 @@ static inline u64 rsvd_bits(int s, int e)
 	return ((1ULL << (e - s + 1)) - 1) << s;
 }
 
-int kvm_mmu_get_spte_hierarchy(struct kvm_vcpu *vcpu, u64 addr, u64 sptes[4]);
 void kvm_mmu_set_mmio_spte_mask(u64 mmio_mask);
 
 void
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 217f663..4cf25b9 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5748,73 +5748,9 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu)
 	return kvm_mmu_page_fault(vcpu, gpa, error_code, NULL, 0);
 }
 
-static u64 ept_rsvd_mask(u64 spte, int level)
-{
-	int i;
-	u64 mask = 0;
-
-	for (i = 51; i > boot_cpu_data.x86_phys_bits; i--)
-		mask |= (1ULL << i);
-
-	if (level == 4)
-		/* bits 7:3 reserved */
-		mask |= 0xf8;
-	else if (spte & (1ULL << 7))
-		/*
-		 * 1GB/2MB page, bits 29:12 or 20:12 reserved respectively,
-		 * level == 1 if the hypervisor is using the ignored bit 7.
-		 */
-		mask |= (PAGE_SIZE << ((level - 1) * 9)) - PAGE_SIZE;
-	else if (level > 1)
-		/* bits 6:3 reserved */
-		mask |= 0x78;
-
-	return mask;
-}
-
-static void ept_misconfig_inspect_spte(struct kvm_vcpu *vcpu, u64 spte,
-				       int level)
-{
-	printk(KERN_ERR "%s: spte 0x%llx level %d\n", __func__, spte, level);
-
-	/* 010b (write-only) */
-	WARN_ON((spte & 0x7) == 0x2);
-
-	/* 110b (write/execute) */
-	WARN_ON((spte & 0x7) == 0x6);
-
-	/* 100b (execute-only) and value not supported by logical processor */
-	if (!cpu_has_vmx_ept_execute_only())
-		WARN_ON((spte & 0x7) == 0x4);
-
-	/* not 000b */
-	if ((spte & 0x7)) {
-		u64 rsvd_bits = spte & ept_rsvd_mask(spte, level);
-
-		if (rsvd_bits != 0) {
-			printk(KERN_ERR "%s: rsvd_bits = 0x%llx\n",
-					 __func__, rsvd_bits);
-			WARN_ON(1);
-		}
-
-		/* bits 5:3 are _not_ reserved for large page or leaf page */
-		if ((rsvd_bits & 0x38) == 0) {
-			u64 ept_mem_type = (spte & 0x38) >> 3;
-
-			if (ept_mem_type == 2 || ept_mem_type == 3 ||
-			    ept_mem_type == 7) {
-				printk(KERN_ERR "%s: ept_mem_type=0x%llx\n",
-						__func__, ept_mem_type);
-				WARN_ON(1);
-			}
-		}
-	}
-}
-
 static int handle_ept_misconfig(struct kvm_vcpu *vcpu)
 {
-	u64 sptes[4];
-	int nr_sptes, i, ret;
+	int ret;
 	gpa_t gpa;
 
 	gpa = vmcs_read64(GUEST_PHYSICAL_ADDRESS);
@@ -5835,13 +5771,7 @@ static int handle_ept_misconfig(struct kvm_vcpu *vcpu)
 		return 1;
 
 	/* It is the real ept misconfig */
-	printk(KERN_ERR "EPT: Misconfiguration.\n");
-	printk(KERN_ERR "EPT: GPA: 0x%llx\n", gpa);
-
-	nr_sptes = kvm_mmu_get_spte_hierarchy(vcpu, gpa, sptes);
-
-	for (i = PT64_ROOT_LEVEL; i > PT64_ROOT_LEVEL - nr_sptes; --i)
-		ept_misconfig_inspect_spte(vcpu, sptes[i-1], i);
+	WARN_ON(1);
 
 	vcpu->run->exit_reason = KVM_EXIT_UNKNOWN;
 	vcpu->run->hw.hardware_exit_reason = EXIT_REASON_EPT_MISCONFIG;
-- 
2.1.0

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