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/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3272a5e..99a71d9 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1064,7 +1064,8 @@ void kvm_mmu_setup(struct kvm_vcpu *vcpu);
void kvm_mmu_init_vm(struct kvm *kvm);
void kvm_mmu_uninit_vm(struct kvm *kvm);
void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
- u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 p_mask);
+ u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 p_mask,
+ u64 acc_track_mask);
void kvm_mmu_reset_context(struct kvm_vcpu *vcpu);
void kvm_mmu_slot_remove_write_access(struct kvm *kvm,
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