diff mbox

KVM: x86: Rework request for immediate exit

Message ID 517CE2EC.5010901@web.de (mailing list archive)
State New, archived
Headers show

Commit Message

Jan Kiszka April 28, 2013, 8:50 a.m. UTC 
From: Jan Kiszka <jan.kiszka@siemens.com>

The VMX implementation of enable_irq_window raised
KVM_REQ_IMMEDIATE_EXIT after we checked it in vcpu_enter_guest. This
caused infinite loops on vmentry. Fix it by letting enable_irq_window
signal the need for an immediate exit via its return value and drop
KVM_REQ_IMMEDIATE_EXIT.

This issue only affects nested VMX scenarios.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 arch/x86/include/asm/kvm_host.h |    2 +-
 arch/x86/kvm/svm.c              |    3 ++-
 arch/x86/kvm/vmx.c              |   15 ++++++++-------
 arch/x86/kvm/x86.c              |    7 +++----
 include/linux/kvm_host.h        |   15 +++++++--------
 5 files changed, 21 insertions(+), 21 deletions(-)

Comments

Marcelo Tosatti May 3, 2013, 1:20 a.m. UTC | #1 
On Sun, Apr 28, 2013 at 10:50:52AM +0200, Jan Kiszka wrote:
> From: Jan Kiszka <jan.kiszka@siemens.com>
> 
> The VMX implementation of enable_irq_window raised
> KVM_REQ_IMMEDIATE_EXIT after we checked it in vcpu_enter_guest. This
> caused infinite loops on vmentry. Fix it by letting enable_irq_window
> signal the need for an immediate exit via its return value and drop
> KVM_REQ_IMMEDIATE_EXIT.
> 
> This issue only affects nested VMX scenarios.
> 
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

Please rebase against "KVM: x86: Account for failing enable_irq_window
for NMI window request".

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Gleb Natapov May 3, 2013, 5:33 a.m. UTC | #2 
On Thu, May 02, 2013 at 10:20:39PM -0300, Marcelo Tosatti wrote:
> On Sun, Apr 28, 2013 at 10:50:52AM +0200, Jan Kiszka wrote:
> > From: Jan Kiszka <jan.kiszka@siemens.com>
> > 
> > The VMX implementation of enable_irq_window raised
> > KVM_REQ_IMMEDIATE_EXIT after we checked it in vcpu_enter_guest. This
> > caused infinite loops on vmentry. Fix it by letting enable_irq_window
> > signal the need for an immediate exit via its return value and drop
> > KVM_REQ_IMMEDIATE_EXIT.
> > 
> > This issue only affects nested VMX scenarios.
> > 
> > Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> 
> Please rebase against "KVM: x86: Account for failing enable_irq_window
> for NMI window request".
This one is applied already. Looks like I forgot to send an email about
it.
 
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			Gleb.
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diff mbox

Patch

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 18635ae..111b4a0 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -694,7 +694,7 @@  struct kvm_x86_ops {
 	bool (*get_nmi_mask)(struct kvm_vcpu *vcpu);
 	void (*set_nmi_mask)(struct kvm_vcpu *vcpu, bool masked);
 	void (*enable_nmi_window)(struct kvm_vcpu *vcpu);
-	void (*enable_irq_window)(struct kvm_vcpu *vcpu);
+	int (*enable_irq_window)(struct kvm_vcpu *vcpu);
 	void (*update_cr8_intercept)(struct kvm_vcpu *vcpu, int tpr, int irr);
 	int (*vm_has_apicv)(struct kvm *kvm);
 	void (*hwapic_irr_update)(struct kvm_vcpu *vcpu, int max_irr);
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index d6713e1..91a7431 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3632,7 +3632,7 @@  static int svm_interrupt_allowed(struct kvm_vcpu *vcpu)
 	return ret;
 }
 
-static void enable_irq_window(struct kvm_vcpu *vcpu)
+static int enable_irq_window(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 
@@ -3646,6 +3646,7 @@  static void enable_irq_window(struct kvm_vcpu *vcpu)
 		svm_set_vintr(svm);
 		svm_inject_irq(svm, 0x0);
 	}
+	return 0;
 }
 
 static void enable_nmi_window(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index d663a59..1795512 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4398,22 +4398,23 @@  static bool nested_exit_on_nmi(struct kvm_vcpu *vcpu)
 		PIN_BASED_NMI_EXITING;
 }
 
-static void enable_irq_window(struct kvm_vcpu *vcpu)
+static int enable_irq_window(struct kvm_vcpu *vcpu)
 {
 	u32 cpu_based_vm_exec_control;
-	if (is_guest_mode(vcpu) && nested_exit_on_intr(vcpu)) {
+
+	if (is_guest_mode(vcpu) && nested_exit_on_intr(vcpu))
 		/*
 		 * We get here if vmx_interrupt_allowed() said we can't
-		 * inject to L1 now because L2 must run. Ask L2 to exit
-		 * right after entry, so we can inject to L1 more promptly.
+		 * inject to L1 now because L2 must run. The caller will have
+		 * to make L2 exit right after entry, so we can inject to L1
+		 * more promptly.
 		 */
-		kvm_make_request(KVM_REQ_IMMEDIATE_EXIT, vcpu);
-		return;
-	}
+		return -EBUSY;
 
 	cpu_based_vm_exec_control = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
 	cpu_based_vm_exec_control |= CPU_BASED_VIRTUAL_INTR_PENDING;
 	vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
+	return 0;
 }
 
 static void enable_nmi_window(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2a434bf..c522260 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5692,7 +5692,7 @@  static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 	int r;
 	bool req_int_win = !irqchip_in_kernel(vcpu->kvm) &&
 		vcpu->run->request_interrupt_window;
-	bool req_immediate_exit = 0;
+	bool req_immediate_exit = false;
 
 	if (vcpu->requests) {
 		if (kvm_check_request(KVM_REQ_MMU_RELOAD, vcpu))
@@ -5734,8 +5734,6 @@  static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 			record_steal_time(vcpu);
 		if (kvm_check_request(KVM_REQ_NMI, vcpu))
 			process_nmi(vcpu);
-		req_immediate_exit =
-			kvm_check_request(KVM_REQ_IMMEDIATE_EXIT, vcpu);
 		if (kvm_check_request(KVM_REQ_PMU, vcpu))
 			kvm_handle_pmu_event(vcpu);
 		if (kvm_check_request(KVM_REQ_PMI, vcpu))
@@ -5757,7 +5755,8 @@  static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 		if (vcpu->arch.nmi_pending)
 			kvm_x86_ops->enable_nmi_window(vcpu);
 		else if (kvm_cpu_has_injectable_intr(vcpu) || req_int_win)
-			kvm_x86_ops->enable_irq_window(vcpu);
+			req_immediate_exit =
+				kvm_x86_ops->enable_irq_window(vcpu) != 0;
 
 		if (kvm_lapic_enabled(vcpu)) {
 			/*
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 93a5005..7bde424 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -119,14 +119,13 @@  static inline bool is_error_page(struct page *page)
 #define KVM_REQ_APF_HALT          12
 #define KVM_REQ_STEAL_UPDATE      13
 #define KVM_REQ_NMI               14
-#define KVM_REQ_IMMEDIATE_EXIT    15
-#define KVM_REQ_PMU               16
-#define KVM_REQ_PMI               17
-#define KVM_REQ_WATCHDOG          18
-#define KVM_REQ_MASTERCLOCK_UPDATE 19
-#define KVM_REQ_MCLOCK_INPROGRESS 20
-#define KVM_REQ_EPR_EXIT          21
-#define KVM_REQ_SCAN_IOAPIC       22
+#define KVM_REQ_PMU               15
+#define KVM_REQ_PMI               16
+#define KVM_REQ_WATCHDOG          17
+#define KVM_REQ_MASTERCLOCK_UPDATE 18
+#define KVM_REQ_MCLOCK_INPROGRESS 19
+#define KVM_REQ_EPR_EXIT          20
+#define KVM_REQ_SCAN_IOAPIC       21
 
 #define KVM_USERSPACE_IRQ_SOURCE_ID		0
 #define KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID	1