[RFC,v6,26/92] kvm: x86: add kvm_mmu_nested_pagefault()

Commit Message

Adalbert Lazăr Aug. 9, 2019, 3:59 p.m. UTC

From: Mihai Donțu <[e-mail]>

This is needed to filter #PF introspection events.

Signed-off-by: Mihai Donțu <[e-mail]>
Co-developed-by: Nicușor Cîțu <[e-mail]>
Signed-off-by: Nicușor Cîțu <[e-mail]>
Signed-off-by: Adalbert Lazăr <[e-mail]>
---
 arch/x86/include/asm/kvm_host.h | 4 ++++
 arch/x86/kvm/mmu.c              | 5 +++++
 arch/x86/kvm/svm.c              | 7 +++++++
 arch/x86/kvm/vmx/vmx.c          | 9 +++++++++
 4 files changed, 25 insertions(+)

Comments

Paolo Bonzini Aug. 13, 2019, 8:12 a.m. UTC | #1

On 09/08/19 17:59, Adalbert Lazăr wrote:
> +static bool vmx_nested_pagefault(struct kvm_vcpu *vcpu)
> +{
> +	if (vcpu->arch.exit_qualification & EPT_VIOLATION_GVA_TRANSLATED)
> +		return false;
> +	return true;
> +}
> +

This hook is misnamed; it has nothing to do with nested virtualization.
 Rather, it returns true if it the failure happened while translating
the address of a guest page table.

SVM makes the same information available in EXITINFO[33].

Paolo

Patch

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 2d6bde6fa59f..7da1137a2b82 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1004,6 +1004,8 @@  struct kvm_x86_ops {
 	bool (*has_emulated_msr)(int index);
 	void (*cpuid_update)(struct kvm_vcpu *vcpu);
 
+	bool (*nested_pagefault)(struct kvm_vcpu *vcpu);
+
 	struct kvm *(*vm_alloc)(void);
 	void (*vm_free)(struct kvm *);
 	int (*vm_init)(struct kvm *kvm);
@@ -1593,4 +1595,6 @@  static inline int kvm_cpu_get_apicid(int mps_cpu)
 #define put_smstate(type, buf, offset, val)                      \
 	*(type *)((buf) + (offset) - 0x7e00) = val
 
+bool kvm_mmu_nested_pagefault(struct kvm_vcpu *vcpu);
+
 #endif /* _ASM_X86_KVM_HOST_H */
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index ff053f17b8c2..9eaf6cc776a9 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -6169,3 +6169,8 @@  void kvm_mmu_module_exit(void)
 	unregister_shrinker(&mmu_shrinker);
 	mmu_audit_disable();
 }
+
+bool kvm_mmu_nested_pagefault(struct kvm_vcpu *vcpu)
+{
+	return kvm_x86_ops->nested_pagefault(vcpu);
+}
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index f13a3a24d360..3c099c56099c 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -7098,6 +7098,11 @@  static int nested_enable_evmcs(struct kvm_vcpu *vcpu,
 	return -ENODEV;
 }
 
+static bool svm_nested_pagefault(struct kvm_vcpu *vcpu)
+{
+	return false;
+}
+
 static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
 	.cpu_has_kvm_support = has_svm,
 	.disabled_by_bios = is_disabled,
@@ -7109,6 +7114,8 @@  static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
 	.cpu_has_accelerated_tpr = svm_cpu_has_accelerated_tpr,
 	.has_emulated_msr = svm_has_emulated_msr,
 
+	.nested_pagefault = svm_nested_pagefault,
+
 	.vcpu_create = svm_create_vcpu,
 	.vcpu_free = svm_free_vcpu,
 	.vcpu_reset = svm_vcpu_reset,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 30a6bcd735ec..e10ee8fd1c67 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7682,6 +7682,13 @@  static __exit void hardware_unsetup(void)
 	free_kvm_area();
 }
 
+static bool vmx_nested_pagefault(struct kvm_vcpu *vcpu)
+{
+	if (vcpu->arch.exit_qualification & EPT_VIOLATION_GVA_TRANSLATED)
+		return false;
+	return true;
+}
+
 static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
 	.cpu_has_kvm_support = cpu_has_kvm_support,
 	.disabled_by_bios = vmx_disabled_by_bios,
@@ -7693,6 +7700,8 @@  static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
 	.cpu_has_accelerated_tpr = report_flexpriority,
 	.has_emulated_msr = vmx_has_emulated_msr,
 
+	.nested_pagefault = vmx_nested_pagefault,
+
 	.vm_init = vmx_vm_init,
 	.vm_alloc = vmx_vm_alloc,
 	.vm_free = vmx_vm_free,