kvm: x86: mmu: Lockless access tracking for Intel CPUs without EPT A bits.
This change implements lockless access tracking for Intel CPUs without EPT
A bits. This is achieved by marking the PTEs as not-present (but not
completely clearing them) when clear_flush_young() is called after marking
the pages as accessed. When an EPT Violation is generated as a result of
the VM accessing those pages, the PTEs are restored to their original values.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index fc061cb..a22a479 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -469,11 +469,14 @@ enum vmcs_field {
#define VMX_EPT_IPAT_BIT (1ull << 6)
#define VMX_EPT_ACCESS_BIT (1ull << 8)
#define VMX_EPT_DIRTY_BIT (1ull << 9)
+#define VMX_EPT_RWX_MASK (VMX_EPT_READABLE_MASK | \
+ VMX_EPT_WRITABLE_MASK | \
+ VMX_EPT_EXECUTABLE_MASK)
+#define VMX_EPT_MT_MASK (7ull << VMX_EPT_MT_EPTE_SHIFT)
/* The mask to use to trigger an EPT Misconfiguration in order to track MMIO */
-#define VMX_EPT_MISCONFIG_WX_VALUE (VMX_EPT_WRITABLE_MASK | \
- VMX_EPT_EXECUTABLE_MASK)
-
+#define VMX_EPT_MISCONFIG_WX_VALUE (VMX_EPT_WRITABLE_MASK | \
+ VMX_EPT_EXECUTABLE_MASK)
#define VMX_EPT_IDENTITY_PAGETABLE_ADDR 0xfffbc000ul