[Devel] [PATCH RHEL7 COMMIT] kvm: x86: mmu: Use symbolic constants for EPT Violation Exit Qualifications

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-693.21.1.vz7.50.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-693.21.1.vz7.47.6
------>
commit b92fadcf94cbaa1005a82e5ff2bb8b336cc0b12c
Author: Junaid Shahid <junaids at google.com>
Date:   Wed May 16 12:50:43 2018 +0300

    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: Junaid Shahid <junaids at google.com>
    Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
    
    (cherry picked from commit 27959a4415a5a00881a7b9353ab9b1274da2ca47)
    Signed-off-by: Jan Dakinevich <jan.dakinevich at virtuozzo.com>
    
    =====================
    Patchset description:
    
    EPT fixes and enhancements
    
    Backport of EPT fixes from upstream for
    https://jira.sw.ru/browse/PSBM-84046
    
    Bandan Das (3):
      kvm: mmu: don't set the present bit unconditionally
      kvm: mmu: track read permission explicitly for shadow EPT page tables
      kvm: vmx: advertise support for ept execute only
    
    Junaid Shahid (2):
      kvm: x86: mmu: Use symbolic constants for EPT Violation Exit
        Qualifications
      kvm: x86: mmu: Rename EPT_VIOLATION_READ/WRITE/INSTR constants
    
    KarimAllah Ahmed (2):
      kvm: Map PFN-type memory regions as writable (if possible)
      KVM: x86: Update the exit_qualification access bits while walking an
        address
    
    Paolo Bonzini (5):
      KVM: nVMX: we support 1GB EPT pages
      kvm: x86: MMU support for EPT accessed/dirty bits
      kvm: nVMX: support EPT accessed/dirty bits
      KVM: MMU: return page fault error code from permission_fault
      KVM: nVMX: fix EPT permissions as reported in exit qualification
---
 arch/x86/include/asm/vmx.h | 16 ++++++++++++++++
 arch/x86/kvm/vmx.c         | 22 ++++++++++++++--------
 2 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index 9f40269360f2..259caeee3b8c 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -467,6 +467,22 @@ 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
  */
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 300293804b91..844fd95bf3ba 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5950,14 +5950,20 @@ 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;