diff mbox

Implement generic double fault generation mechanism

Message ID 9832F13BD22FB94A829F798DA4A8280501A80F02A3@pdsmsx503.ccr.corp.intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Dong, Eddie April 30, 2009, 7:24 a.m. UTC 
Move Double-Fault generation logic out of page fault
    exception generating function to cover more generic case.
    
    Signed-off-by: Eddie Dong <eddie.dong@intel.com>

Comments

Gleb Natapov May 3, 2009, 10:53 a.m. UTC | #1 
On Thu, Apr 30, 2009 at 03:24:07PM +0800, Dong, Eddie wrote:
> 
> 
>     Move Double-Fault generation logic out of page fault
>     exception generating function to cover more generic case.
>     
>     Signed-off-by: Eddie Dong <eddie.dong@intel.com>
> 
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index ab1fdac..51a8dad 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -162,12 +162,59 @@ void kvm_set_apic_base(struct kvm_vcpu *vcpu, u64 data)
>  }
>  EXPORT_SYMBOL_GPL(kvm_set_apic_base);
>  
> +#define EXCPT_BENIGN		0
> +#define EXCPT_CONTRIBUTORY	1
> +#define EXCPT_PF		2
> +
> +static int exception_class(int vector)
> +{
> +	if (vector == 14)
> +		return EXCPT_PF;
> +	else if (vector == 0 || (vector >= 10 && vector <= 13))
> +		return EXCPT_CONTRIBUTORY;
> +	else
> +		return EXCPT_BENIGN;
> +}
> +
This makes double fault (8) benign exception. Surely not what you want.

> +static void kvm_multiple_exception(struct kvm_vcpu *vcpu,
> +		unsigned nr, bool has_error, u32 error_code)
> +{
> +	u32 prev_nr;
> +	int class1, class2;
> +
> +	if (!vcpu->arch.exception.pending) {
> +		vcpu->arch.exception.pending = true;
> +		vcpu->arch.exception.has_error_code = has_error;
> +		vcpu->arch.exception.nr = nr;
> +		vcpu->arch.exception.error_code = error_code;
> +		return;
> +	}
> +
> +	/* to check exception */
> +	prev_nr = vcpu->arch.exception.nr;
> +	class2 = exception_class(nr);
> +	class1 = exception_class(prev_nr);
> +	if ((class1 == EXCPT_CONTRIBUTORY && class2 == EXCPT_CONTRIBUTORY)
> +		|| (class1 == EXCPT_PF && class2 != EXCPT_BENIGN)) {
> +		/* generate double fault per SDM Table 5-5 */
> +		printk(KERN_DEBUG "kvm: double fault 0x%x on 0x%x\n",
> +			prev_nr, nr);
> +		vcpu->arch.exception.pending = true;
> +		vcpu->arch.exception.has_error_code = 1;
> +		vcpu->arch.exception.nr = DF_VECTOR;
> +		vcpu->arch.exception.error_code = 0;
> +		if (prev_nr == DF_VECTOR) {
> +			/* triple fault -> shutdown */
> +			set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);
> +		}
> +	} else
> +		printk(KERN_ERR "Exception 0x%x on 0x%x happens serially\n",
> +			prev_nr, nr);
> +}
When two exceptions happens serially is is better to replace pending exception
with a new one. This way the first exception (that is lost) will be regenerated
when instruction will be re-executed.

--
			Gleb.
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Dong, Eddie May 8, 2009, 8:19 a.m. UTC | #2 
Dong, Eddie wrote:
>     Move Double-Fault generation logic out of page fault
>     exception generating function to cover more generic case.
> 
>     Signed-off-by: Eddie Dong <eddie.dong@intel.com>
> 
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index ab1fdac..51a8dad 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -162,12 +162,59 @@ void kvm_set_apic_base(struct kvm_vcpu *vcpu,
>  u64 data) }
>  EXPORT_SYMBOL_GPL(kvm_set_apic_base);
> 
> +#define EXCPT_BENIGN		0
> +#define EXCPT_CONTRIBUTORY	1
> +#define EXCPT_PF		2
> +
> +static int exception_class(int vector)
> +{
> +	if (vector == 14)
> +		return EXCPT_PF;
> +	else if (vector == 0 || (vector >= 10 && vector <= 13))
> +		return EXCPT_CONTRIBUTORY;
> +	else
> +		return EXCPT_BENIGN;
> +}
> +
> +static void kvm_multiple_exception(struct kvm_vcpu *vcpu,
> +		unsigned nr, bool has_error, u32 error_code)
> +{
> +	u32 prev_nr;
> +	int class1, class2;
> +
> +	if (!vcpu->arch.exception.pending) {
> +		vcpu->arch.exception.pending = true;
> +		vcpu->arch.exception.has_error_code = has_error;
> +		vcpu->arch.exception.nr = nr;
> +		vcpu->arch.exception.error_code = error_code;
> +		return;
> +	}
> +
> +	/* to check exception */
> +	prev_nr = vcpu->arch.exception.nr;
> +	class2 = exception_class(nr);
> +	class1 = exception_class(prev_nr);
> +	if ((class1 == EXCPT_CONTRIBUTORY && class2 == EXCPT_CONTRIBUTORY)
> +		|| (class1 == EXCPT_PF && class2 != EXCPT_BENIGN)) {
> +		/* generate double fault per SDM Table 5-5 */
> +		printk(KERN_DEBUG "kvm: double fault 0x%x on 0x%x\n",
> +			prev_nr, nr);
> +		vcpu->arch.exception.pending = true;
> +		vcpu->arch.exception.has_error_code = 1;
> +		vcpu->arch.exception.nr = DF_VECTOR;
> +		vcpu->arch.exception.error_code = 0;
> +		if (prev_nr == DF_VECTOR) {
> +			/* triple fault -> shutdown */
> +			set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);
> +		}
> +	} else
> +		printk(KERN_ERR "Exception 0x%x on 0x%x happens serially\n",
> +			prev_nr, nr);
> +}
> +
>  void kvm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr)
>  {
> -	WARN_ON(vcpu->arch.exception.pending);
> -	vcpu->arch.exception.pending = true;
> -	vcpu->arch.exception.has_error_code = false;
> -	vcpu->arch.exception.nr = nr;
> +	kvm_multiple_exception(vcpu, nr, false, 0);
>  }
>  EXPORT_SYMBOL_GPL(kvm_queue_exception);
> 
> @@ -176,18 +223,6 @@ void kvm_inject_page_fault(struct kvm_vcpu
>  *vcpu, unsigned long addr, {
>  	++vcpu->stat.pf_guest;
> 
> -	if (vcpu->arch.exception.pending) {
> -		if (vcpu->arch.exception.nr == PF_VECTOR) {
> -			printk(KERN_DEBUG "kvm: inject_page_fault:"
> -					" double fault 0x%lx\n", addr);
> -			vcpu->arch.exception.nr = DF_VECTOR;
> -			vcpu->arch.exception.error_code = 0;
> -		} else if (vcpu->arch.exception.nr == DF_VECTOR) {
> -			/* triple fault -> shutdown */
> -			set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);
> -		}
> -		return;
> -	}
>  	vcpu->arch.cr2 = addr;
>  	kvm_queue_exception_e(vcpu, PF_VECTOR, error_code);
>  }
> @@ -200,11 +235,7 @@ EXPORT_SYMBOL_GPL(kvm_inject_nmi);
> 
>  void kvm_queue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32
>  error_code) {
> -	WARN_ON(vcpu->arch.exception.pending);
> -	vcpu->arch.exception.pending = true;
> -	vcpu->arch.exception.has_error_code = true;
> -	vcpu->arch.exception.nr = nr;
> -	vcpu->arch.exception.error_code = error_code;
> +	kvm_multiple_exception(vcpu, nr, true, error_code);
>  }
>  EXPORT_SYMBOL_GPL(kvm_queue_exception_e);



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Avi Kivity May 8, 2009, 8:28 a.m. UTC | #3 
Dong, Eddie wrote:


No content (except for quoted message)?
diff mbox

Patch

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ab1fdac..51a8dad 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -162,12 +162,59 @@  void kvm_set_apic_base(struct kvm_vcpu *vcpu, u64 data)
 }
 EXPORT_SYMBOL_GPL(kvm_set_apic_base);
 
+#define EXCPT_BENIGN		0
+#define EXCPT_CONTRIBUTORY	1
+#define EXCPT_PF		2
+
+static int exception_class(int vector)
+{
+	if (vector == 14)
+		return EXCPT_PF;
+	else if (vector == 0 || (vector >= 10 && vector <= 13))
+		return EXCPT_CONTRIBUTORY;
+	else
+		return EXCPT_BENIGN;
+}
+
+static void kvm_multiple_exception(struct kvm_vcpu *vcpu,
+		unsigned nr, bool has_error, u32 error_code)
+{
+	u32 prev_nr;
+	int class1, class2;
+
+	if (!vcpu->arch.exception.pending) {
+		vcpu->arch.exception.pending = true;
+		vcpu->arch.exception.has_error_code = has_error;
+		vcpu->arch.exception.nr = nr;
+		vcpu->arch.exception.error_code = error_code;
+		return;
+	}
+
+	/* to check exception */
+	prev_nr = vcpu->arch.exception.nr;
+	class2 = exception_class(nr);
+	class1 = exception_class(prev_nr);
+	if ((class1 == EXCPT_CONTRIBUTORY && class2 == EXCPT_CONTRIBUTORY)
+		|| (class1 == EXCPT_PF && class2 != EXCPT_BENIGN)) {
+		/* generate double fault per SDM Table 5-5 */
+		printk(KERN_DEBUG "kvm: double fault 0x%x on 0x%x\n",
+			prev_nr, nr);
+		vcpu->arch.exception.pending = true;
+		vcpu->arch.exception.has_error_code = 1;
+		vcpu->arch.exception.nr = DF_VECTOR;
+		vcpu->arch.exception.error_code = 0;
+		if (prev_nr == DF_VECTOR) {
+			/* triple fault -> shutdown */
+			set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);
+		}
+	} else
+		printk(KERN_ERR "Exception 0x%x on 0x%x happens serially\n",
+			prev_nr, nr);
+}
+
 void kvm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr)
 {
-	WARN_ON(vcpu->arch.exception.pending);
-	vcpu->arch.exception.pending = true;
-	vcpu->arch.exception.has_error_code = false;
-	vcpu->arch.exception.nr = nr;
+	kvm_multiple_exception(vcpu, nr, false, 0);
 }
 EXPORT_SYMBOL_GPL(kvm_queue_exception);
 
@@ -176,18 +223,6 @@  void kvm_inject_page_fault(struct kvm_vcpu *vcpu, unsigned long addr,
 {
 	++vcpu->stat.pf_guest;
 
-	if (vcpu->arch.exception.pending) {
-		if (vcpu->arch.exception.nr == PF_VECTOR) {
-			printk(KERN_DEBUG "kvm: inject_page_fault:"
-					" double fault 0x%lx\n", addr);
-			vcpu->arch.exception.nr = DF_VECTOR;
-			vcpu->arch.exception.error_code = 0;
-		} else if (vcpu->arch.exception.nr == DF_VECTOR) {
-			/* triple fault -> shutdown */
-			set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);
-		}
-		return;
-	}
 	vcpu->arch.cr2 = addr;
 	kvm_queue_exception_e(vcpu, PF_VECTOR, error_code);
 }
@@ -200,11 +235,7 @@  EXPORT_SYMBOL_GPL(kvm_inject_nmi);
 
 void kvm_queue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code)
 {
-	WARN_ON(vcpu->arch.exception.pending);
-	vcpu->arch.exception.pending = true;
-	vcpu->arch.exception.has_error_code = true;
-	vcpu->arch.exception.nr = nr;
-	vcpu->arch.exception.error_code = error_code;
+	kvm_multiple_exception(vcpu, nr, true, error_code);
 }
 EXPORT_SYMBOL_GPL(kvm_queue_exception_e);