diff mbox

[3/7] KVM: arm: guest debug, add stub KVM_SET_GUEST_DEBUG ioctl

Message ID 1416931805-23223-4-git-send-email-alex.bennee@linaro.org
State Superseded, archived
Headers show

Commit Message

Alex Bennée Nov. 25, 2014, 4:10 p.m. UTC 
This commit adds a stub function to support the KVM_SET_GUEST_DEBUG
ioctl. Currently any operation flag will return EINVAL. Actual
functionality will be added with further patches.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>.

Comments

Alex Bennée Nov. 26, 2014, 3:03 p.m. UTC | #1 
Andrew Jones <drjones@redhat.com> writes:

> On Tue, Nov 25, 2014 at 04:10:01PM +0000, Alex Bennée wrote:
>> This commit adds a stub function to support the KVM_SET_GUEST_DEBUG
>> ioctl. Currently any operation flag will return EINVAL. Actual
>> functionality will be added with further patches.
>
> Technically the stub is already there, and you're extending it to
> start looking at control flags, but still not doing anything yet.

Sure we do:

>>  int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
>>  					struct kvm_guest_debug *dbg)
>>  {
>> -	return -EINVAL;
>> +	/* If it's not enabled clear all flags */
>> +	if (!(dbg->control & KVM_GUESTDBG_ENABLE)) {
>> +		vcpu->guest_debug = 0;
>> +		return 0;
>> +	}

That's some class non-functionality right there ;-)

>> +	vcpu->guest_debug = dbg->control;
>> +	kvm_info("%s: guest_debug is 0x%lx\n", __func__, vcpu->guest_debug);
>> +
>> +	/* Single Step */
>> +	if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) {
>> +		kvm_info("SS requested, not yet implemented\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	/* Software Break Points */
>> +	if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) {
>> +		kvm_info("SW BP support requested, not yet implemented\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	/* Hardware assisted Break and Watch points */
>> +	if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
>> +		kvm_info("HW BP support requested, not yet implemented\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	return 0;
>>  }
>
> I guess all the kvm_info's were useful for developing this patch series,
> but do we still need them?

They also served the very useful roll of stopping checkpatch.pl bitching
about my reluctance to remove braces from the if () { } clauses. However
I take your point. I can certainly remove the kvm_info() statements as
each bit of functionality is added while leaving this one to help when
someone is bisecting and confused.
Christoffer Dall Nov. 29, 2014, 4:21 p.m. UTC | #2 
On Tue, Nov 25, 2014 at 04:10:01PM +0000, Alex Bennée wrote:
> This commit adds a stub function to support the KVM_SET_GUEST_DEBUG
> ioctl. Currently any operation flag will return EINVAL. Actual
> functionality will be added with further patches.
> 
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>.
> 
> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
> index 7610eaa..2c6386e 100644
> --- a/Documentation/virtual/kvm/api.txt
> +++ b/Documentation/virtual/kvm/api.txt
> @@ -2570,7 +2570,7 @@ handled.
>  4.87 KVM_SET_GUEST_DEBUG
>  
>  Capability: KVM_CAP_SET_GUEST_DEBUG
> -Architectures: x86, s390, ppc
> +Architectures: x86, s390, ppc, arm64
>  Type: vcpu ioctl
>  Parameters: struct kvm_guest_debug (in)
>  Returns: 0 on success; -1 on error
> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
> index 9e193c8..a0ff410 100644
> --- a/arch/arm/kvm/arm.c
> +++ b/arch/arm/kvm/arm.c
> @@ -180,6 +180,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
>  	case KVM_CAP_ARM_PSCI:
>  	case KVM_CAP_ARM_PSCI_0_2:
>  	case KVM_CAP_READONLY_MEM:
> +	case KVM_CAP_SET_GUEST_DEBUG:

Don't we usually wait with introducing visibility to user space until
you actually do support the ioctl?

>  		r = 1;
>  		break;
>  	case KVM_CAP_COALESCED_MMIO:
> @@ -302,7 +303,34 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
>  int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
>  					struct kvm_guest_debug *dbg)
>  {
> -	return -EINVAL;
> +	/* If it's not enabled clear all flags */
> +	if (!(dbg->control & KVM_GUESTDBG_ENABLE)) {
> +		vcpu->guest_debug = 0;
> +		return 0;
> +	}
> +
> +	vcpu->guest_debug = dbg->control;
> +	kvm_info("%s: guest_debug is 0x%lx\n", __func__, vcpu->guest_debug);
> +
> +	/* Single Step */
> +	if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) {
> +		kvm_info("SS requested, not yet implemented\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Software Break Points */
> +	if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) {
> +		kvm_info("SW BP support requested, not yet implemented\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Hardware assisted Break and Watch points */
> +	if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
> +		kvm_info("HW BP support requested, not yet implemented\n");
> +		return -EINVAL;
> +	}
> +
> +	return 0;
>  }
>  
>  
> -- 
> 2.1.3
> 
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diff mbox

Patch

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 7610eaa..2c6386e 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2570,7 +2570,7 @@  handled.
 4.87 KVM_SET_GUEST_DEBUG
 
 Capability: KVM_CAP_SET_GUEST_DEBUG
-Architectures: x86, s390, ppc
+Architectures: x86, s390, ppc, arm64
 Type: vcpu ioctl
 Parameters: struct kvm_guest_debug (in)
 Returns: 0 on success; -1 on error
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 9e193c8..a0ff410 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -180,6 +180,7 @@  int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_ARM_PSCI:
 	case KVM_CAP_ARM_PSCI_0_2:
 	case KVM_CAP_READONLY_MEM:
+	case KVM_CAP_SET_GUEST_DEBUG:
 		r = 1;
 		break;
 	case KVM_CAP_COALESCED_MMIO:
@@ -302,7 +303,34 @@  void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
 					struct kvm_guest_debug *dbg)
 {
-	return -EINVAL;
+	/* If it's not enabled clear all flags */
+	if (!(dbg->control & KVM_GUESTDBG_ENABLE)) {
+		vcpu->guest_debug = 0;
+		return 0;
+	}
+
+	vcpu->guest_debug = dbg->control;
+	kvm_info("%s: guest_debug is 0x%lx\n", __func__, vcpu->guest_debug);
+
+	/* Single Step */
+	if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) {
+		kvm_info("SS requested, not yet implemented\n");
+		return -EINVAL;
+	}
+
+	/* Software Break Points */
+	if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) {
+		kvm_info("SW BP support requested, not yet implemented\n");
+		return -EINVAL;
+	}
+
+	/* Hardware assisted Break and Watch points */
+	if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
+		kvm_info("HW BP support requested, not yet implemented\n");
+		return -EINVAL;
+	}
+
+	return 0;
 }