From c8dc56e08be84b830ba7ad959b56cdbc3f99c5d6 Mon Sep 17 00:00:00 2001
From: Yonghua Huang <yonghua.huang@intel.com>
Date: Wed, 21 Mar 2018 01:05:50 +0800
Subject: [PATCH] Add APIC ACCESS VMexit handler

Update 'apic_access_exit_handler()' function to emulate
guest instruments to read/write guest's lapic registers page

Signed-off-by: Yonghua Huang <yonghua.huang@intel.com>
---
 arch/x86/guest/vlapic.c         | 30 ++++++++++++++++++++++++++++--
 arch/x86/vmexit.c               |  2 +-
 include/arch/x86/guest/vlapic.h |  2 +-
 include/arch/x86/vmx.h          | 14 ++++++++++++++
 4 files changed, 44 insertions(+), 4 deletions(-)

diff --git a/arch/x86/guest/vlapic.c b/arch/x86/guest/vlapic.c
index bc6e7498b..7b403669d 100644
--- a/arch/x86/guest/vlapic.c
+++ b/arch/x86/guest/vlapic.c
@@ -37,6 +37,9 @@
 #include <bsp_extern.h>
 #include <hv_debug.h>
 
+#include "instr_emul_wrapper.h"
+#include "instr_emul.h"
+
 #include "time.h"
 #include "vlapic_priv.h"
 
@@ -2331,9 +2334,32 @@ apicv_inject_pir(struct vlapic *vlapic)
 	}
 }
 
-int apicv_access_exit_handler(__unused struct vcpu *vcpu)
+int apic_access_exit_handler(struct vcpu *vcpu)
 {
-	TRACE_2L(TRC_VMEXIT_APICV_ACCESS, 0, 0);
+	bool ret;
+	int access_type, offset;
+	uint64_t qual;
+	struct vlapic *vlapic;
+
+	qual =  vcpu->arch_vcpu.exit_qualification;
+	access_type = APIC_ACCESS_TYPE(qual);
+
+	/*parse offset if linear access*/
+	if (access_type <= 3)
+		offset = APIC_ACCESS_OFFSET(qual);
+
+	vlapic = vcpu->arch_vcpu.vlapic;
+
+	analyze_instruction(vcpu, &vcpu->mmio);
+	if (access_type == 1) {
+		if (!emulate_instruction(vcpu, &vcpu->mmio))
+			vlapic_write(vlapic, 1, offset, vcpu->mmio.value, &ret);
+	} else if (access_type == 0) {
+		vlapic_read(vlapic, 1, offset, &vcpu->mmio.value, &ret);
+		emulate_instruction(vcpu, &vcpu->mmio);
+	}
+
+	TRACE_2L(TRC_VMEXIT_APICV_ACCESS, qual, (uint64_t)vlapic);
 	return 0;
 }
 
diff --git a/arch/x86/vmexit.c b/arch/x86/vmexit.c
index 6c3be515b..2464fe9e4 100644
--- a/arch/x86/vmexit.c
+++ b/arch/x86/vmexit.c
@@ -125,7 +125,7 @@ static const struct vm_exit_dispatch dispatch_table[] = {
 	[VMX_EXIT_REASON_TPR_BELOW_THRESHOLD] = {
 		.handler = unhandled_vmexit_handler},
 	[VMX_EXIT_REASON_APIC_ACCESS] = {
-		.handler = apicv_access_exit_handler,
+		.handler = apic_access_exit_handler,
 		.need_exit_qualification = 1},
 	[VMX_EXIT_REASON_VIRTUALIZED_EOI] = {
 		.handler = apicv_virtualized_eoi_exit_handler,
diff --git a/include/arch/x86/guest/vlapic.h b/include/arch/x86/guest/vlapic.h
index 0ef8eb93c..61f9dbb34 100644
--- a/include/arch/x86/guest/vlapic.h
+++ b/include/arch/x86/guest/vlapic.h
@@ -125,7 +125,7 @@ uint64_t apicv_get_apic_access_addr(struct vm *vm);
 uint64_t apicv_get_apic_page_addr(struct vlapic *vlapic);
 bool vlapic_apicv_enabled(struct vcpu *vcpu);
 void apicv_inject_pir(struct vlapic *vlapic);
-int apicv_access_exit_handler(struct vcpu *vcpu);
+int apic_access_exit_handler(struct vcpu *vcpu);
 int apicv_write_exit_handler(struct vcpu *vcpu);
 int apicv_virtualized_eoi_exit_handler(struct vcpu *vcpu);
 
diff --git a/include/arch/x86/vmx.h b/include/arch/x86/vmx.h
index 284f13495..34507d625 100644
--- a/include/arch/x86/vmx.h
+++ b/include/arch/x86/vmx.h
@@ -351,6 +351,20 @@
 #define VMX_INT_TYPE_HW_EXP		3
 #define VMX_INT_TYPE_SW_EXP		6
 
+/*VM exit qulifications for APIC-access
+ * Access type:
+ *  0  = linear access for a data read during instruction execution
+ *  1  = linear access for a data write during instruction execution
+ *  2  = linear access for an instruction fetch
+ *  3  = linear access (read or write) during event delivery
+ *  10 = guest-physical access during event delivery
+ *  15 = guest-physical access for an instructon fetch or during
+ *       instruction execution
+ */
+#define APIC_ACCESS_TYPE(qual)		(((qual) >> 12) & 0xF)
+#define APIC_ACCESS_OFFSET(qual)	((qual) & 0xFFF)
+
+
 #define VM_SUCCESS	0
 #define VM_FAIL		-1