Merge tag 'kvm-x86-vmx-6.10' of https://github.com/kvm-x86/linux into HEAD

KVM VMX changes for 6.10:

 - Clear vmcs.EXIT_QUALIFICATION when synthesizing an EPT Misconfig VM-Exit to
   L1, as per the SDM.

 - Move kvm_vcpu_arch's exit_qualification into x86_exception, as the field is
   used only when synthesizing nested EPT violation, i.e. it's not the vCPU's
   "real" exit_qualification, which is tracked elsewhere.

 - Add a sanity check to assert that EPT Violations are the only sources of
   nested PML Full VM-Exits.

5 files changed, 34 insertions, 16 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 69862e8ecab3..ece45b3f6f20 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -997,9 +997,6 @@ struct kvm_vcpu_arch {
 
 	u64 msr_kvm_poll_control;
 
-	/* set at EPT violation at this point */
-	unsigned long exit_qualification;
-
 	/* pv related host specific info */
 	struct {
 		bool pv_unhalted;
diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h
index 5382646162a3..29ea4313e1bb 100644
--- a/arch/x86/kvm/kvm_emulate.h
+++ b/arch/x86/kvm/kvm_emulate.h
@@ -26,6 +26,7 @@ struct x86_exception {
 	bool nested_page_fault;
 	u64 address; /* cr2 or nested page fault gpa */
 	u8 async_page_fault;
+	unsigned long exit_qualification;
 };
 
 /*
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 9aac3aa93d88..d3dbcf382ed2 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -497,21 +497,21 @@ error:
 	 * The other bits are set to 0.
 	 */
 	if (!(errcode & PFERR_RSVD_MASK)) {
-		vcpu->arch.exit_qualification &= (EPT_VIOLATION_GVA_IS_VALID |
-						  EPT_VIOLATION_GVA_TRANSLATED);
+		walker->fault.exit_qualification = 0;
+
 		if (write_fault)
-			vcpu->arch.exit_qualification |= EPT_VIOLATION_ACC_WRITE;
+			walker->fault.exit_qualification |= EPT_VIOLATION_ACC_WRITE;
 		if (user_fault)
-			vcpu->arch.exit_qualification |= EPT_VIOLATION_ACC_READ;
+			walker->fault.exit_qualification |= EPT_VIOLATION_ACC_READ;
 		if (fetch_fault)
-			vcpu->arch.exit_qualification |= EPT_VIOLATION_ACC_INSTR;
+			walker->fault.exit_qualification |= EPT_VIOLATION_ACC_INSTR;
 
 		/*
 		 * Note, pte_access holds the raw RWX bits from the EPTE, not
 		 * ACC_*_MASK flags!
 		 */
-		vcpu->arch.exit_qualification |= (pte_access & VMX_EPT_RWX_MASK) <<
-						 EPT_VIOLATION_RWX_SHIFT;
+		walker->fault.exit_qualification |= (pte_access & VMX_EPT_RWX_MASK) <<
+						     EPT_VIOLATION_RWX_SHIFT;
 	}
 #endif
 	walker->fault.address = addr;
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index d05ddf751491..d5b832126e34 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -409,18 +409,40 @@ static void nested_ept_inject_page_fault(struct kvm_vcpu *vcpu,
 {
 	struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
+	unsigned long exit_qualification;
 	u32 vm_exit_reason;
-	unsigned long exit_qualification = vcpu->arch.exit_qualification;
 
 	if (vmx->nested.pml_full) {
 		vm_exit_reason = EXIT_REASON_PML_FULL;
 		vmx->nested.pml_full = false;
-		exit_qualification &= INTR_INFO_UNBLOCK_NMI;
+
+		/*
+		 * It should be impossible to trigger a nested PML Full VM-Exit
+		 * for anything other than an EPT Violation from L2.  KVM *can*
+		 * trigger nEPT page fault injection in response to an EPT
+		 * Misconfig, e.g. if the MMIO SPTE was stale and L1's EPT
+		 * tables also changed, but KVM should not treat EPT Misconfig
+		 * VM-Exits as writes.
+		 */
+		WARN_ON_ONCE(vmx->exit_reason.basic != EXIT_REASON_EPT_VIOLATION);
+
+		/*
+		 * PML Full and EPT Violation VM-Exits both use bit 12 to report
+		 * "NMI unblocking due to IRET", i.e. the bit can be propagated
+		 * as-is from the original EXIT_QUALIFICATION.
+		 */
+		exit_qualification = vmx_get_exit_qual(vcpu) & INTR_INFO_UNBLOCK_NMI;
 	} else {
-		if (fault->error_code & PFERR_RSVD_MASK)
+		if (fault->error_code & PFERR_RSVD_MASK) {
 			vm_exit_reason = EXIT_REASON_EPT_MISCONFIG;
-		else
+			exit_qualification = 0;
+		} else {
+			exit_qualification = fault->exit_qualification;
+			exit_qualification |= vmx_get_exit_qual(vcpu) &
+					      (EPT_VIOLATION_GVA_IS_VALID |
+					       EPT_VIOLATION_GVA_TRANSLATED);
 			vm_exit_reason = EXIT_REASON_EPT_VIOLATION;
+		}
 
 		/*
 		 * Although the caller (kvm_inject_emulated_page_fault) would
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index ad36e5eb6667..51b2cd13250a 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5783,8 +5783,6 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu)
 	error_code |= (exit_qualification & EPT_VIOLATION_GVA_TRANSLATED) != 0 ?
 	       PFERR_GUEST_FINAL_MASK : PFERR_GUEST_PAGE_MASK;
 
-	vcpu->arch.exit_qualification = exit_qualification;
-
 	/*
 	 * Check that the GPA doesn't exceed physical memory limits, as that is
 	 * a guest page fault.  We have to emulate the instruction here, because