[RFC PATCH v4 12/18] kvm: x86: hook in kvmi_breakpoint_event()

["Adalber Lazăr" <alazar@bitdefender.com>]

From: Adalbert Lazar <alazar@bitdefender.com>

Inform the guest introspection tool that a breakpoint instruction (INT3)
is being executed. These one-byte intructions are placed in the slack
space of various functions and used as notification for when the OS or
an application has reached a certain state or is trying to perform a
certain operation (like creating a process).

Signed-off-by: Mihai Donțu <mdontu@bitdefender.com>
---
 arch/x86/kvm/svm.c |  6 ++++++
 arch/x86/kvm/vmx.c | 15 +++++++++++----
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index f41e4d7008d7..8903e0c58609 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -18,6 +18,7 @@
 #define pr_fmt(fmt) "SVM: " fmt
 
 #include <linux/kvm_host.h>
+#include <linux/kvmi.h>
 
 #include "irq.h"
 #include "mmu.h"
@@ -45,6 +46,7 @@
 #include <asm/debugreg.h>
 #include <asm/kvm_para.h>
 #include <asm/irq_remapping.h>
+#include <asm/kvmi.h>
 
 #include <asm/virtext.h>
 #include "trace.h"
@@ -2194,6 +2196,10 @@ static int bp_interception(struct vcpu_svm *svm)
 {
 	struct kvm_run *kvm_run = svm->vcpu.run;
 
+	if (kvmi_breakpoint_event(&svm->vcpu,
+		svm->vmcb->save.cs.base + svm->vmcb->save.rip))
+		return 1;
+
 	kvm_run->exit_reason = KVM_EXIT_DEBUG;
 	kvm_run->debug.arch.pc = svm->vmcb->save.cs.base + svm->vmcb->save.rip;
 	kvm_run->debug.arch.exception = BP_VECTOR;
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c03580abf9e8..fbdfa8507d4f 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -51,6 +51,7 @@
 #include <asm/apic.h>
 #include <asm/irq_remapping.h>
 #include <asm/mmu_context.h>
+#include <asm/kvmi.h>
 
 #include "trace.h"
 #include "pmu.h"
@@ -5904,7 +5905,7 @@ static int handle_exception(struct kvm_vcpu *vcpu)
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	struct kvm_run *kvm_run = vcpu->run;
 	u32 intr_info, ex_no, error_code;
-	unsigned long cr2, rip, dr6;
+	unsigned long cr2, dr6;
 	u32 vect_info;
 	enum emulation_result er;
 
@@ -5978,7 +5979,13 @@ static int handle_exception(struct kvm_vcpu *vcpu)
 		kvm_run->debug.arch.dr6 = dr6 | DR6_FIXED_1;
 		kvm_run->debug.arch.dr7 = vmcs_readl(GUEST_DR7);
 		/* fall through */
-	case BP_VECTOR:
+	case BP_VECTOR: {
+		unsigned long gva = vmcs_readl(GUEST_CS_BASE) +
+			kvm_rip_read(vcpu);
+
+		if (kvmi_breakpoint_event(vcpu, gva))
+			return 1;
+
 		/*
 		 * Update instruction length as we may reinject #BP from
 		 * user space while in guest debugging mode. Reading it for
@@ -5987,10 +5994,10 @@ static int handle_exception(struct kvm_vcpu *vcpu)
 		vmx->vcpu.arch.event_exit_inst_len =
 			vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
 		kvm_run->exit_reason = KVM_EXIT_DEBUG;
-		rip = kvm_rip_read(vcpu);
-		kvm_run->debug.arch.pc = vmcs_readl(GUEST_CS_BASE) + rip;
+		kvm_run->debug.arch.pc = gva;
 		kvm_run->debug.arch.exception = ex_no;
 		break;
+	}
 	default:
 		kvm_run->exit_reason = KVM_EXIT_EXCEPTION;
 		kvm_run->ex.exception = ex_no;