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From: Sean Christopherson <seanjc@google.com>
To: Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Jim Mattson <jmattson@google.com>,
	Maxim Levitsky <mlevitsk@redhat.com>,
	Oliver Upton <oupton@google.com>, Peter Shier <pshier@google.com>
Subject: [PATCH v4 14/24] KVM: x86: Use kvm_queue_exception_e() to queue #DF
Date: Sat, 23 Jul 2022 00:51:27 +0000	[thread overview]
Message-ID: <20220723005137.1649592-15-seanjc@google.com> (raw)
In-Reply-To: <20220723005137.1649592-1-seanjc@google.com>

Queue #DF by recursing on kvm_multiple_exception() by way of
kvm_queue_exception_e() instead of open coding the behavior.  This will
allow KVM to Just Work when a future commit moves exception interception
checks (for L2 => L1) into kvm_multiple_exception().

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 arch/x86/kvm/x86.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 027fc518ba75..041149c0cf02 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -663,25 +663,22 @@ static void kvm_multiple_exception(struct kvm_vcpu *vcpu,
 	}
 	class1 = exception_class(prev_nr);
 	class2 = exception_class(nr);
-	if ((class1 == EXCPT_CONTRIBUTORY && class2 == EXCPT_CONTRIBUTORY)
-		|| (class1 == EXCPT_PF && class2 != EXCPT_BENIGN)) {
+	if ((class1 == EXCPT_CONTRIBUTORY && class2 == EXCPT_CONTRIBUTORY) ||
+	    (class1 == EXCPT_PF && class2 != EXCPT_BENIGN)) {
 		/*
-		 * Generate double fault per SDM Table 5-5.  Set
-		 * exception.pending = true so that the double fault
-		 * can trigger a nested vmexit.
+		 * Synthesize #DF.  Clear the previously injected or pending
+		 * exception so as not to incorrectly trigger shutdown.
 		 */
-		vcpu->arch.exception.pending = true;
 		vcpu->arch.exception.injected = false;
-		vcpu->arch.exception.has_error_code = true;
-		vcpu->arch.exception.vector = DF_VECTOR;
-		vcpu->arch.exception.error_code = 0;
-		vcpu->arch.exception.has_payload = false;
-		vcpu->arch.exception.payload = 0;
-	} else
+		vcpu->arch.exception.pending = false;
+
+		kvm_queue_exception_e(vcpu, DF_VECTOR, 0);
+	} else {
 		/* replace previous exception with a new one in a hope
 		   that instruction re-execution will regenerate lost
 		   exception */
 		goto queue;
+	}
 }
 
 void kvm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr)
-- 
2.37.1.359.gd136c6c3e2-goog


  parent reply	other threads:[~2022-07-23  0:53 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-23  0:51 [PATCH v4 00/24] KVM: x86: Event/exception fixes and cleanups Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 01/24] KVM: nVMX: Unconditionally purge queued/injected events on nested "exit" Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 02/24] KVM: VMX: Drop bits 31:16 when shoving exception error code into VMCS Sean Christopherson
2022-08-01 16:00   ` Maxim Levitsky
2022-07-23  0:51 ` [PATCH v4 03/24] KVM: x86: Don't check for code breakpoints when emulating on exception Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 04/24] KVM: nVMX: Treat General Detect #DB (DR7.GD=1) as fault-like Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 05/24] KVM: nVMX: Prioritize TSS T-flag #DBs over Monitor Trap Flag Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 06/24] KVM: x86: Treat #DBs from the emulator as fault-like (code and DR7.GD=1) Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 07/24] KVM: x86: Use DR7_GD macro instead of open coding check in emulator Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 08/24] KVM: nVMX: Ignore SIPI that arrives in L2 when vCPU is not in WFS Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 09/24] KVM: nVMX: Unconditionally clear mtf_pending on nested VM-Exit Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 10/24] KVM: VMX: Inject #PF on ENCLS as "emulated" #PF Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 11/24] KVM: x86: Rename kvm_x86_ops.queue_exception to inject_exception Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 12/24] KVM: x86: Make kvm_queued_exception a properly named, visible struct Sean Christopherson
2022-08-01 16:10   ` Maxim Levitsky
2022-07-23  0:51 ` [PATCH v4 13/24] KVM: x86: Formalize blocking of nested pending exceptions Sean Christopherson
2022-07-23  0:51 ` Sean Christopherson [this message]
2022-07-23  0:51 ` [PATCH v4 15/24] KVM: x86: Hoist nested event checks above event injection logic Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 16/24] KVM: x86: Evaluate ability to inject SMI/NMI/IRQ after potential VM-Exit Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 17/24] KVM: nVMX: Add a helper to identify low-priority #DB traps Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 18/24] KVM: nVMX: Document priority of all known events on Intel CPUs Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 19/24] KVM: x86: Morph pending exceptions to pending VM-Exits at queue time Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 20/24] KVM: x86: Treat pending TRIPLE_FAULT requests as pending exceptions Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 21/24] KVM: VMX: Update MTF and ICEBP comments to document KVM's subtle behavior Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 22/24] KVM: x86: Rename inject_pending_events() to kvm_check_and_inject_events() Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 23/24] KVM: selftests: Use uapi header to get VMX and SVM exit reasons/codes Sean Christopherson
2022-07-23  0:51 ` [PATCH v4 24/24] KVM: selftests: Add an x86-only test to verify nested exception queueing Sean Christopherson

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