KVM: TDX/VMX: rework EPT_VIOLATION_EXEC_FOR_RING3_LIN into PROT_MASK

EPT exit qualification bit 6 is used when mode-based execute control
is enabled, and reflects user executable addresses. Rework name to
reflect the intention and add to EPT_VIOLATION_PROT_MASK, which allows
simplifying the return evaluation in
tdx_is_sept_violation_unexpected_pending a pinch.

Rework handling in __vmx_handle_ept_violation to unconditionally clear
EPT_VIOLATION_PROT_USER_EXEC until MBEC is implemented, as suggested by
Sean [1].

Note: Intel SDM Table 29-7 defines bit 6 as:
  If the "mode-based execute control" VM-execution control is 0, the
  value of this bit is undefined. If that control is 1, this bit is the
  logical-AND of bit 10 in the EPT paging-structure entries used to
  translate the guest-physical address of the access causing the EPT
  violation. In this case, it indicates whether the guest-physical
  address was executable for user-mode linear addresses.

[1] https://lore.kernel.org/all/aCJDzU1p_SFNRIJd@google.com/

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Jon Kohler <jon@nutanix.com>
Message-ID: <20251223054806.1611168-2-jon@nutanix.com>
Tested-by: David Riley <d.riley@proxmox.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 37080382df54865d352415266e8c5a8330236c3c..b2291a766e3f7023ab1f7bec648677decdae4281 100644 (file)
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -608,10 +608,11 @@ enum vm_entry_failure_code {
 #define EPT_VIOLATION_PROT_READ                BIT(3)
 #define EPT_VIOLATION_PROT_WRITE       BIT(4)
 #define EPT_VIOLATION_PROT_EXEC                BIT(5)
-#define EPT_VIOLATION_EXEC_FOR_RING3_LIN BIT(6)
+#define EPT_VIOLATION_PROT_USER_EXEC   BIT(6)
 #define EPT_VIOLATION_PROT_MASK                (EPT_VIOLATION_PROT_READ  | \
                                         EPT_VIOLATION_PROT_WRITE | \
-                                        EPT_VIOLATION_PROT_EXEC)
+                                        EPT_VIOLATION_PROT_EXEC  | \
+                                        EPT_VIOLATION_PROT_USER_EXEC)
 #define EPT_VIOLATION_GVA_IS_VALID     BIT(7)
 #define EPT_VIOLATION_GVA_TRANSLATED   BIT(8)
 

diff --git a/arch/x86/kvm/vmx/common.h b/arch/x86/kvm/vmx/common.h
index 412d0829d7a21777c5969ba27293721e9aa3d1c5..adf925500b9e02bce2f23d7882255ec7664a671f 100644 (file)
--- a/arch/x86/kvm/vmx/common.h
+++ b/arch/x86/kvm/vmx/common.h
@@ -94,8 +94,13 @@ static inline int __vmx_handle_ept_violation(struct kvm_vcpu *vcpu, gpa_t gpa,
        /* Is it a fetch fault? */
        error_code |= (exit_qualification & EPT_VIOLATION_ACC_INSTR)
                      ? PFERR_FETCH_MASK : 0;
-       /* ept page table entry is present? */
-       error_code |= (exit_qualification & EPT_VIOLATION_PROT_MASK)
+       /*
+        * ept page table entry is present?
+        * note: unconditionally clear USER_EXEC until mode-based
+        * execute control is implemented
+        */
+       error_code |= (exit_qualification &
+                      (EPT_VIOLATION_PROT_MASK & ~EPT_VIOLATION_PROT_USER_EXEC))
                      ? PFERR_PRESENT_MASK : 0;
 
        if (exit_qualification & EPT_VIOLATION_GVA_IS_VALID)

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 1e47c194af53c71ea45da7b998d4b5d0d3dcccde..89f9fe30435d926f66692b10039d6b2cee960264 100644 (file)
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -1845,7 +1845,7 @@ static inline bool tdx_is_sept_violation_unexpected_pending(struct kvm_vcpu *vcp
        if (eeq_type != TDX_EXT_EXIT_QUAL_TYPE_PENDING_EPT_VIOLATION)
                return false;
 
-       return !(eq & EPT_VIOLATION_PROT_MASK) && !(eq & EPT_VIOLATION_EXEC_FOR_RING3_LIN);
+       return !(eq & EPT_VIOLATION_PROT_MASK);
 }
 
 static int tdx_handle_ept_violation(struct kvm_vcpu *vcpu)