kvm: x86: mmu: Use symbolic constants for EPT Violation Exit Qualifications

This change adds some symbolic constants for VM Exit Qualifications
related to EPT Violations and updates handle_ept_violation() to use
these constants instead of hard-coded numbers.
Signed-off-by: NJunaid Shahid <junaids@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/vmx.h

@@ -499,6 +499,22 @@ struct vmx_msr_entry {
 #define ENTRY_FAIL_NMI			3
 #define ENTRY_FAIL_VMCS_LINK_PTR	4
 
+/*
+ * Exit Qualifications for EPT Violations
+ */
+#define EPT_VIOLATION_READ_BIT		0
+#define EPT_VIOLATION_WRITE_BIT		1
+#define EPT_VIOLATION_INSTR_BIT		2
+#define EPT_VIOLATION_READABLE_BIT	3
+#define EPT_VIOLATION_WRITABLE_BIT	4
+#define EPT_VIOLATION_EXECUTABLE_BIT	5
+#define EPT_VIOLATION_READ		(1 << EPT_VIOLATION_READ_BIT)
+#define EPT_VIOLATION_WRITE		(1 << EPT_VIOLATION_WRITE_BIT)
+#define EPT_VIOLATION_INSTR		(1 << EPT_VIOLATION_INSTR_BIT)
+#define EPT_VIOLATION_READABLE		(1 << EPT_VIOLATION_READABLE_BIT)
+#define EPT_VIOLATION_WRITABLE		(1 << EPT_VIOLATION_WRITABLE_BIT)
+#define EPT_VIOLATION_EXECUTABLE	(1 << EPT_VIOLATION_EXECUTABLE_BIT)
+
 /*
  * VM-instruction error numbers
  */

arch/x86/kvm/vmx.c

@@ -6374,14 +6374,20 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu)
 	gpa = vmcs_read64(GUEST_PHYSICAL_ADDRESS);
 	trace_kvm_page_fault(gpa, exit_qualification);
 
-	/* it is a read fault? */
-	error_code = (exit_qualification << 2) & PFERR_USER_MASK;
-	/* it is a write fault? */
-	error_code |= exit_qualification & PFERR_WRITE_MASK;
-	/* It is a fetch fault? */
-	error_code |= (exit_qualification << 2) & PFERR_FETCH_MASK;
-	/* ept page table is present? */
-	error_code |= (exit_qualification & 0x38) != 0;
+	/* Is it a read fault? */
+	error_code = (exit_qualification & EPT_VIOLATION_READ)
+		     ? PFERR_USER_MASK : 0;
+	/* Is it a write fault? */
+	error_code |= (exit_qualification & EPT_VIOLATION_WRITE)
+		      ? PFERR_WRITE_MASK : 0;
+	/* Is it a fetch fault? */
+	error_code |= (exit_qualification & EPT_VIOLATION_INSTR)
+		      ? PFERR_FETCH_MASK : 0;
+	/* ept page table entry is present? */
+	error_code |= (exit_qualification &
+		       (EPT_VIOLATION_READABLE | EPT_VIOLATION_WRITABLE |
+			EPT_VIOLATION_EXECUTABLE))
+		      ? PFERR_PRESENT_MASK : 0;
 
 	vcpu->arch.exit_qualification = exit_qualification;