[PATCH 1/3] KVM - Add missing kvm_run initializations

[PATCH 1/3] KVM - Add missing kvm_run initializations

[Jeff Dike]

There are a bunch of missing initializations of run->exit_reason and
associated data.

kvm_hypercall wasn't setting exit_reason at all.

When exit_reason is KVM_EXIT_MMIO, the mmio data isn't initialized.  I
don't know what it should be, so I just stuck a FIXME in there.

There were some missing initializations of hardware_exit_reason with
KVM_EXIT_UNKNOWN, so I added those.  One case had exit_reason = 0,
which I changed to KVM_EXIT_UNKNOWN.

I did a pass over all of the return 0 paths in the exit handler
callbacks, so this should cover everything.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
--
 drivers/kvm/kvm_main.c |    3 +++
 drivers/kvm/svm.c      |    3 +++
 drivers/kvm/vmx.c      |    4 +++-
 3 files changed, 9 insertions(+), 1 deletion(-)

Index: kvm/drivers/kvm/kvm_main.c
===================================================================
--- kvm.orig/drivers/kvm/kvm_main.c
+++ kvm/drivers/kvm/kvm_main.c
@@ -1370,6 +1370,7 @@ int kvm_hypercall(struct kvm_vcpu *vcpu,
 		run->hypercall.ret = ret;
 		run->hypercall.longmode = is_long_mode(vcpu);
 		kvm_arch_ops->decache_regs(vcpu);
+		run->exit_reason = KVM_EXIT_HYPERCALL;
 		return 0;
 	}
 	vcpu->regs[VCPU_REGS_RAX] = ret;
@@ -1928,6 +1929,8 @@ static int kvm_vcpu_ioctl_run(struct kvm
 		if (r == EMULATE_DO_MMIO) {
 			/*
 			 * Read-modify-write.  Back to userspace.
+			 *
+			 * FIXME - kvm_run->mmio not initialized
 			 */
 			kvm_run->exit_reason = KVM_EXIT_MMIO;
 			r = 0;
Index: kvm/drivers/kvm/svm.c
===================================================================
--- kvm.orig/drivers/kvm/svm.c
+++ kvm/drivers/kvm/svm.c
@@ -929,6 +929,7 @@ static int pf_interception(struct kvm_vc
 		return 1;
 	case EMULATE_DO_MMIO:
 		++vcpu->stat.mmio_exits;
+		/* FIXME - kvm_run->mmio not initialized */
 		kvm_run->exit_reason = KVM_EXIT_MMIO;
 		return 0;
 	case EMULATE_FAIL:
@@ -938,6 +939,7 @@ static int pf_interception(struct kvm_vc
 		BUG();
 	}
 
+	kvm_run->hw.hardware_exit_reason = vcpu->svm->vmcb->control.exit_code;
 	kvm_run->exit_reason = KVM_EXIT_UNKNOWN;
 	return 0;
 }
@@ -1135,6 +1137,7 @@ static int invalid_op_interception(struc
 static int task_switch_interception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 {
 	printk(KERN_DEBUG "%s: task swiche is unsupported\n", __FUNCTION__);
+	kvm_run->hw.hardware_exit_reason = vcpu->svm->vmcb->control.exit_code;
 	kvm_run->exit_reason = KVM_EXIT_UNKNOWN;
 	return 0;
 }
Index: kvm/drivers/kvm/vmx.c
===================================================================
--- kvm.orig/drivers/kvm/vmx.c
+++ kvm/drivers/kvm/vmx.c
@@ -1610,6 +1610,7 @@ static int handle_exception(struct kvm_v
 			return 1;
 		case EMULATE_DO_MMIO:
 			++vcpu->stat.mmio_exits;
+			/* FIXME - kvm_run->mmio not initialized */
 			kvm_run->exit_reason = KVM_EXIT_MMIO;
 			return 0;
 		 case EMULATE_FAIL:
@@ -1807,7 +1808,8 @@ static int handle_cr(struct kvm_vcpu *vc
 	default:
 		break;
 	}
-	kvm_run->exit_reason = 0;
+	kvm_run->exit_reason = KVM_EXIT_UNKNOWN;
+	kvm_run->hw.hardware_exit_reason = vmcs_read32(VM_EXIT_REASON);
 	printk(KERN_ERR "kvm: unhandled control register: op %d cr %d\n",
 	       (int)(exit_qualification >> 4) & 3, cr);
 	return 0;

Re: [PATCH 1/3] KVM - Add missing kvm_run initializations

[Avi Kivity]

Jeff Dike wrote:
> There are a bunch of missing initializations of run->exit_reason and
> associated data.
>
> kvm_hypercall wasn't setting exit_reason at all.
>
> When exit_reason is KVM_EXIT_MMIO, the mmio data isn't initialized.  I
> don't know what it should be, so I just stuck a FIXME in there.
>
> There were some missing initializations of hardware_exit_reason with
> KVM_EXIT_UNKNOWN, so I added those.  One case had exit_reason = 0,
> which I changed to KVM_EXIT_UNKNOWN.
>
> I did a pass over all of the return 0 paths in the exit handler
> callbacks, so this should cover everything.
>
> Signed-off-by: Jeff Dike <jdike@linux.intel.com>
> --
>  drivers/kvm/kvm_main.c |    3 +++
>  drivers/kvm/svm.c      |    3 +++
>  drivers/kvm/vmx.c      |    4 +++-
>  3 files changed, 9 insertions(+), 1 deletion(-)
>
> Index: kvm/drivers/kvm/kvm_main.c
> ===================================================================
> --- kvm.orig/drivers/kvm/kvm_main.c
> +++ kvm/drivers/kvm/kvm_main.c
> @@ -1370,6 +1370,7 @@ int kvm_hypercall(struct kvm_vcpu *vcpu,
>  		run->hypercall.ret = ret;
>  		run->hypercall.longmode = is_long_mode(vcpu);
>  		kvm_arch_ops->decache_regs(vcpu);
> +		run->exit_reason = KVM_EXIT_HYPERCALL;
>  		return 0;
>  	}
>   

Aye. (And: aiiieee)

>  	vcpu->regs[VCPU_REGS_RAX] = ret;
> @@ -1928,6 +1929,8 @@ static int kvm_vcpu_ioctl_run(struct kvm
>  		if (r == EMULATE_DO_MMIO) {
>  			/*
>  			 * Read-modify-write.  Back to userspace.
> +			 *
> +			 * FIXME - kvm_run->mmio not initialized
>  			 */
>  			kvm_run->exit_reason = KVM_EXIT_MMIO;
>  			r = 0;
>   

I believe that emulate_instruction will set run->mmio if it returns 
EMULATE_DO_MMIO.

> Index: kvm/drivers/kvm/svm.c
> ===================================================================
> --- kvm.orig/drivers/kvm/svm.c
> +++ kvm/drivers/kvm/svm.c
> @@ -929,6 +929,7 @@ static int pf_interception(struct kvm_vc
>  		return 1;
>  	case EMULATE_DO_MMIO:
>  		++vcpu->stat.mmio_exits;
> +		/* FIXME - kvm_run->mmio not initialized */
>  		kvm_run->exit_reason = KVM_EXIT_MMIO;
>   

Ditto.

The rest are all good.

-- 
error compiling committee.c: too many arguments to function

Re: [PATCH 1/3] KVM - Add missing kvm_run initializations

[Jeff Dike]

On Tue, Jul 17, 2007 at 11:12:53AM +0300, Avi Kivity wrote:
> I believe that emulate_instruction will set run->mmio if it returns 
> EMULATE_DO_MMIO.

Righto, forgot to check that.  How about this patch instead?

Set exit_reason to KVM_EXIT_MMIO where run->mmio is initialized.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
--
 drivers/kvm/kvm_main.c |    2 +-
 drivers/kvm/svm.c      |    1 -
 drivers/kvm/vmx.c      |    1 -
 3 files changed, 1 insertion(+), 3 deletions(-)

Index: kvm/drivers/kvm/kvm_main.c
===================================================================
--- kvm.orig/drivers/kvm/kvm_main.c
+++ kvm/drivers/kvm/kvm_main.c
@@ -1294,6 +1294,7 @@ int emulate_instruction(struct kvm_vcpu 
 	r = x86_emulate_memop(&emulate_ctxt, &emulate_ops);
 
 	if ((r || vcpu->mmio_is_write) && run) {
+		run->exit_reason = KVM_EXIT_MMIO;
 		run->mmio.phys_addr = vcpu->mmio_phys_addr;
 		memcpy(run->mmio.data, vcpu->mmio_data, 8);
 		run->mmio.len = vcpu->mmio_size;
@@ -1929,7 +1930,6 @@ static int kvm_vcpu_ioctl_run(struct kvm
 			/*
 			 * Read-modify-write.  Back to userspace.
 			 */
-			kvm_run->exit_reason = KVM_EXIT_MMIO;
 			r = 0;
 			goto out;
 		}
Index: kvm/drivers/kvm/svm.c
===================================================================
--- kvm.orig/drivers/kvm/svm.c
+++ kvm/drivers/kvm/svm.c
@@ -929,7 +929,6 @@ static int pf_interception(struct kvm_vc
 		return 1;
 	case EMULATE_DO_MMIO:
 		++vcpu->stat.mmio_exits;
-		kvm_run->exit_reason = KVM_EXIT_MMIO;
 		return 0;
 	case EMULATE_FAIL:
 		vcpu_printf(vcpu, "%s: emulate fail\n", __FUNCTION__);
Index: kvm/drivers/kvm/vmx.c
===================================================================
--- kvm.orig/drivers/kvm/vmx.c
+++ kvm/drivers/kvm/vmx.c
@@ -1610,7 +1610,6 @@ static int handle_exception(struct kvm_v
 			return 1;
 		case EMULATE_DO_MMIO:
 			++vcpu->stat.mmio_exits;
-			kvm_run->exit_reason = KVM_EXIT_MMIO;
 			return 0;
 		 case EMULATE_FAIL:
 			vcpu_printf(vcpu, "%s: emulate fail\n", __FUNCTION__);

-- 
Work email - jdike at linux dot intel dot com

Re: [PATCH 1/3] KVM - Add missing kvm_run initializations

[Avi Kivity]

Jeff Dike wrote:
> On Tue, Jul 17, 2007 at 11:12:53AM +0300, Avi Kivity wrote:
>   
>> I believe that emulate_instruction will set run->mmio if it returns 
>> EMULATE_DO_MMIO.
>>     
>
> Righto, forgot to check that.  How about this patch instead?
>
> Set exit_reason to KVM_EXIT_MMIO where run->mmio is initialized.
>
>   

Applied, thanks.

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.