[15/21] KVM: x86: Use kvm_queue_exception_e() to queue #DF

Message ID	20220311032801.3467418-16-seanjc@google.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <kvm-owner@kernel.org> Reply-To: Sean Christopherson <seanjc@google.com> Date: Fri, 11 Mar 2022 03:27:55 +0000 In-Reply-To: <20220311032801.3467418-1-seanjc@google.com> Message-Id: <20220311032801.3467418-16-seanjc@google.com> Mime-Version: 1.0 References: <20220311032801.3467418-1-seanjc@google.com> Subject: [PATCH 15/21] KVM: x86: Use kvm_queue_exception_e() to queue #DF From: Sean Christopherson <seanjc@google.com> To: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <seanjc@google.com>, Vitaly Kuznetsov <vkuznets@redhat.com>, Wanpeng Li <wanpengli@tencent.com>, Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Oliver Upton <oupton@google.com>, Peter Shier <pshier@google.com> Content-Type: text/plain; charset="UTF-8" Precedence: bulk
Series	KVM: x86: Event/exception fixes and cleanups \| expand [00/21] KVM: x86: Event/exception fixes and cleanups [01/21] KVM: x86: Return immediately from x86_emulate_instruction() on code #DB [02/21] KVM: nVMX: Unconditionally purge queued/injected events on nested "exit" [03/21] KVM: VMX: Drop bits 31:16 when shoving exception error code into VMCS [04/21] KVM: x86: Don't check for code breakpoints when emulating on exception [05/21] KVM: nVMX: Treat General Detect #DB (DR7.GD=1) as fault-like [06/21] KVM: nVMX: Prioritize TSS T-flag #DBs over Monitor Trap Flag [07/21] KVM: x86: Treat #DBs from the emulator as fault-like (code and DR7.GD=1) [08/21] KVM: x86: Use DR7_GD macro instead of open coding check in emulator [09/21] KVM: nVMX: Ignore SIPI that arrives in L2 when vCPU is not in WFS [10/21] KVM: nVMX: Unconditionally clear mtf_pending on nested VM-Exit [11/21] KVM: VMX: Inject #PF on ENCLS as "emulated" #PF [12/21] KVM: x86: Rename kvm_x86_ops.queue_exception to inject_exception [13/21] KVM: x86: Make kvm_queued_exception a properly named, visible struct [14/21] KVM: x86: Formalize blocking of nested pending exceptions [15/21] KVM: x86: Use kvm_queue_exception_e() to queue #DF [16/21] KVM: x86: Hoist nested event checks above event injection logic [17/21] KVM: x86: Evaluate ability to inject SMI/NMI/IRQ after potential VM-Exit [18/21] KVM: x86: Morph pending exceptions to pending VM-Exits at queue time [19/21] KVM: VMX: Update MTF and ICEBP comments to document KVM's subtle behavior [20/21] KVM: selftests: Use uapi header to get VMX and SVM exit reasons/codes [21/21] KVM: selftests: Add an x86-only test to verify nested exception queueing

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20220311032801.3467418-16-seanjc@google.com (mailing list archive)

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Reply-To: Sean Christopherson <seanjc@google.com>
Date: Fri, 11 Mar 2022 03:27:55 +0000
In-Reply-To: <20220311032801.3467418-1-seanjc@google.com>
Message-Id: <20220311032801.3467418-16-seanjc@google.com>
Mime-Version: 1.0
References: <20220311032801.3467418-1-seanjc@google.com>
Subject: [PATCH 15/21] KVM: x86: Use kvm_queue_exception_e() to queue #DF
From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, Oliver Upton <oupton@google.com>,
        Peter Shier <pshier@google.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Series

KVM: x86: Event/exception fixes and cleanups | expand

Commit Message

Sean Christopherson March 11, 2022, 3:27 a.m. UTC

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>
---
 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 74843767383c..d6fbff896263 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -669,25 +669,22 @@  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)

[15/21] KVM: x86: Use kvm_queue_exception_e() to queue #DF

Commit Message

Patch