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From: Sean Christopherson <sean.j.christopherson@intel.com>
To: "Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.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
Subject: [RESEND PATCH 10/13] KVM: x86: Handle emulation failure directly in kvm_task_switch()
Date: Thu, 22 Aug 2019 18:07:06 -0700	[thread overview]
Message-ID: <20190823010709.24879-11-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20190823010709.24879-1-sean.j.christopherson@intel.com>

Consolidate the reporting of emulation failure into kvm_task_switch()
so that it can return EMULATE_USER_EXIT.  This helps pave the way for
removing EMULATE_FAIL altogether.

This also fixes a theoretical bug where task switch interception could
suppress an EMULATE_USER_EXIT return.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/svm.c     | 11 ++---------
 arch/x86/kvm/vmx/vmx.c | 14 +++-----------
 arch/x86/kvm/x86.c     |  9 ++++++---
 3 files changed, 11 insertions(+), 23 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index c8e3bef2d586..d9d88cecaba6 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3888,17 +3888,10 @@ static int task_switch_interception(struct vcpu_svm *svm)
 	if (int_type != SVM_EXITINTINFO_TYPE_SOFT)
 		int_vec = -1;
 
-	if (kvm_task_switch(&svm->vcpu, tss_selector, int_vec, reason,
-				has_error_code, error_code) == EMULATE_FAIL)
-		goto fail;
 
-	return 1;
 
-fail:
-	svm->vcpu.run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
-	svm->vcpu.run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
-	svm->vcpu.run->internal.ndata = 0;
-	return 0;
+	return kvm_task_switch(&svm->vcpu, tss_selector, int_vec, reason,
+			       has_error_code, error_code) != EMULATE_USER_EXIT;
 }
 
 static int cpuid_interception(struct vcpu_svm *svm)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 25410c58c758..52d5705ff7dc 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5068,21 +5068,13 @@ static int handle_task_switch(struct kvm_vcpu *vcpu)
 		       type != INTR_TYPE_NMI_INTR))
 		skip_emulated_instruction(vcpu);
 
-	if (kvm_task_switch(vcpu, tss_selector,
-			    type == INTR_TYPE_SOFT_INTR ? idt_index : -1, reason,
-			    has_error_code, error_code) == EMULATE_FAIL) {
-		vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
-		vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
-		vcpu->run->internal.ndata = 0;
-		return 0;
-	}
-
 	/*
 	 * TODO: What about debug traps on tss switch?
 	 *       Are we supposed to inject them and update dr6?
 	 */
-
-	return 1;
+	return kvm_task_switch(vcpu, tss_selector,
+			       type == INTR_TYPE_SOFT_INTR ? idt_index : -1,
+			       reason, has_error_code, error_code) != EMULATE_USER_EXIT;
 }
 
 static int handle_ept_violation(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1a886ec6957d..83b3c7e9fce7 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8587,9 +8587,12 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int idt_index,
 
 	ret = emulator_task_switch(ctxt, tss_selector, idt_index, reason,
 				   has_error_code, error_code);
-
-	if (ret)
-		return EMULATE_FAIL;
+	if (ret) {
+		vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+		vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
+		vcpu->run->internal.ndata = 0;
+		return EMULATE_USER_EXIT;
+	}
 
 	kvm_rip_write(vcpu, ctxt->eip);
 	kvm_set_rflags(vcpu, ctxt->eflags);
-- 
2.22.0


  parent reply	other threads:[~2019-08-23  1:07 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-23  1:06 [RESEND PATCH 00/13] KVM: x86: Remove emulation_result enums Sean Christopherson
2019-08-23  1:06 ` [RESEND PATCH 01/13] KVM: x86: Relocate MMIO exit stats counting Sean Christopherson
2019-08-23  9:15   ` Vitaly Kuznetsov
2019-08-23 14:37     ` Sean Christopherson
2019-08-23  1:06 ` [RESEND PATCH 02/13] KVM: x86: Clean up handle_emulation_failure() Sean Christopherson
2019-08-23  9:23   ` Vitaly Kuznetsov
2019-08-23 12:58     ` Liran Alon
2019-08-23  1:06 ` [RESEND PATCH 03/13] KVM: x86: Refactor kvm_vcpu_do_singlestep() to remove out param Sean Christopherson
2019-08-23  9:32   ` Vitaly Kuznetsov
2019-08-23 13:05   ` Liran Alon
2019-08-23  1:07 ` [RESEND PATCH 04/13] KVM: x86: Drop EMULTYPE_NO_UD_ON_FAIL as a standalone type Sean Christopherson
2019-08-23  9:34   ` Vitaly Kuznetsov
2019-08-23 13:21   ` Liran Alon
2019-08-23 13:32     ` Liran Alon
2019-08-23 21:55       ` Sean Christopherson
2019-08-23  1:07 ` [RESEND PATCH 05/13] KVM: x86: Don't attempt VMWare emulation on #GP with non-zero error code Sean Christopherson
2019-08-23 11:51   ` Vitaly Kuznetsov
2019-08-23 13:23   ` Liran Alon
2019-08-23  1:07 ` [RESEND PATCH 06/13] KVM: x86: Move #GP injection for VMware into x86_emulate_instruction() Sean Christopherson
2019-08-23 12:27   ` Vitaly Kuznetsov
2019-08-23 13:30   ` Liran Alon
2019-08-23  1:07 ` [RESEND PATCH 07/13] KVM: x86: Add explicit flag for forced emulation on #UD Sean Christopherson
2019-08-23 13:47   ` Liran Alon
2019-08-23 14:44     ` Sean Christopherson
2019-08-23 15:31       ` Liran Alon
2019-08-23  1:07 ` [RESEND PATCH 08/13] KVM: x86: Move #UD injection for failed emulation into emulation code Sean Christopherson
2019-08-23 13:48   ` Liran Alon
2019-08-27 20:22     ` Sean Christopherson
2019-08-23  1:07 ` [RESEND PATCH 09/13] KVM: x86: Exit to userspace on emulation skip failure Sean Christopherson
2019-08-23  1:07 ` Sean Christopherson [this message]
2019-08-23  1:07 ` [RESEND PATCH 11/13] KVM: x86: Move triple fault request into RM int injection Sean Christopherson
2019-08-23  1:07 ` [RESEND PATCH 12/13] KVM: VMX: Remove EMULATE_FAIL handling in handle_invalid_guest_state() Sean Christopherson
2019-08-23  1:07 ` [RESEND PATCH 13/13] KVM: x86: Remove emulation_result enums, EMULATE_{DONE,FAIL,USER_EXIT} Sean Christopherson

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