Thread (88 messages) 88 messages, 3 authors, 2020-07-22
STALE2158d

[PATCH v9 11/84] KVM: x86: add .cr3_write_intercepted()

From: Adalbert Lazăr <hidden>
Date: 2020-07-21 21:17:47
Also in: kvm
Subsystem: kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers: Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen

From: Nicușor Cîțu <redacted>

This function will be used to allow the introspection tool to disable the
CR3-write interception when it is no longer interested in these events,
but only if nothing else depends on these VM-exits.

Signed-off-by: Nicușor Cîțu <redacted>
Signed-off-by: Adalbert Lazăr <redacted>
---
 arch/x86/include/asm/kvm_host.h | 1 +
 arch/x86/kvm/svm/svm.c          | 8 ++++++++
 arch/x86/kvm/vmx/vmx.c          | 8 ++++++++
 3 files changed, 17 insertions(+)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 89c0bd6529a5..ac45aacc9fc0 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1117,6 +1117,7 @@ struct kvm_x86_ops {
 	int (*set_cr4)(struct kvm_vcpu *vcpu, unsigned long cr4);
 	void (*control_cr3_intercept)(struct kvm_vcpu *vcpu, int type,
 				      bool enable);
+	bool (*cr3_write_intercepted)(struct kvm_vcpu *vcpu);
 	void (*set_efer)(struct kvm_vcpu *vcpu, u64 efer);
 	void (*get_idt)(struct kvm_vcpu *vcpu, struct desc_ptr *dt);
 	void (*set_idt)(struct kvm_vcpu *vcpu, struct desc_ptr *dt);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index f14fc940538b..7a4ec6fbffb9 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1609,6 +1609,13 @@ static void svm_control_cr3_intercept(struct kvm_vcpu *vcpu, int type,
 			 clr_cr_intercept(svm, INTERCEPT_CR3_WRITE);
 }
 
+static bool svm_cr3_write_intercepted(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	return is_cr_intercept(svm, INTERCEPT_CR3_WRITE);
+}
+
 static void svm_set_segment(struct kvm_vcpu *vcpu,
 			    struct kvm_segment *var, int seg)
 {
@@ -4022,6 +4029,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.set_cr0 = svm_set_cr0,
 	.set_cr4 = svm_set_cr4,
 	.control_cr3_intercept = svm_control_cr3_intercept,
+	.cr3_write_intercepted = svm_cr3_write_intercepted,
 	.set_efer = svm_set_efer,
 	.get_idt = svm_get_idt,
 	.set_idt = svm_set_idt,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 6b9639703560..61eb64cf25c7 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -3020,6 +3020,13 @@ static void vmx_control_cr3_intercept(struct kvm_vcpu *vcpu, int type,
 		exec_controls_clearbit(vmx, cr3_exec_control);
 }
 
+static bool vmx_cr3_write_intercepted(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_vmx *vmx = to_vmx(vcpu);
+
+	return !!(exec_controls_get(vmx) & CPU_BASED_CR3_LOAD_EXITING);
+}
+
 static void ept_update_paging_mode_cr0(unsigned long *hw_cr0,
 					unsigned long cr0,
 					struct kvm_vcpu *vcpu)
@@ -7890,6 +7897,7 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
 	.set_cr0 = vmx_set_cr0,
 	.set_cr4 = vmx_set_cr4,
 	.control_cr3_intercept = vmx_control_cr3_intercept,
+	.cr3_write_intercepted = vmx_cr3_write_intercepted,
 	.set_efer = vmx_set_efer,
 	.get_idt = vmx_get_idt,
 	.set_idt = vmx_set_idt,
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