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[PATCH V7 7/9] vfio, platform: make reset driver a requirement by default

Started bySinan Kaya <okaya@codeaurora.org>
First post2016-06-13 06:30 +0200
Last post2016-06-16 19:10 +0200
Articles 3 — 2 participants

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  [PATCH V7 7/9] vfio, platform: make reset driver a requirement by default Sinan Kaya <okaya@codeaurora.org> - 2016-06-13 06:30 +0200
    Re: [PATCH V7 7/9] vfio, platform: make reset driver a requirement by  default Auger Eric <eric.auger@redhat.com> - 2016-06-16 10:20 +0200
      Re: [PATCH V7 7/9] vfio, platform: make reset driver a requirement by  default Sinan Kaya <okaya@codeaurora.org> - 2016-06-16 19:10 +0200

#1420438 — [PATCH V7 7/9] vfio, platform: make reset driver a requirement by default

FromSinan Kaya <okaya@codeaurora.org>
Date2016-06-13 06:30 +0200
Subject[PATCH V7 7/9] vfio, platform: make reset driver a requirement by default
Message-ID<rJrFD-1gJ-19@gated-at.bofh.it>
The code was allowing platform devices to be used without a supporting
VFIO reset driver. The hardware can be left in some inconsistent state
after a guest machine abort.

The reset driver will put the hardware back to safe state and disable
interrupts before returning the control back to the host machine.

Adding a new reset_required kernel module option to AMBA and platform
VFIO drivers with a default value of true.

New requirements are:
1. A reset function needs to be implemented by the corresponding driver
via DT/ACPI.
2. The reset function needs to be discovered via DT/ACPI.

The probe of the driver will fail if any of the above conditions are
not satisfied.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
---
 drivers/vfio/platform/vfio_amba.c             |  5 +++++
 drivers/vfio/platform/vfio_platform.c         |  5 +++++
 drivers/vfio/platform/vfio_platform_common.c  | 22 +++++++++++++++-------
 drivers/vfio/platform/vfio_platform_private.h |  1 +
 4 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/drivers/vfio/platform/vfio_amba.c b/drivers/vfio/platform/vfio_amba.c
index a66479b..7585902 100644
--- a/drivers/vfio/platform/vfio_amba.c
+++ b/drivers/vfio/platform/vfio_amba.c
@@ -23,6 +23,10 @@
 #define DRIVER_AUTHOR   "Antonios Motakis <a.motakis@virtualopensystems.com>"
 #define DRIVER_DESC     "VFIO for AMBA devices - User Level meta-driver"
 
+static bool reset_required = true;
+module_param(reset_required, bool, 0644);
+MODULE_PARM_DESC(reset_required, "override reset requirement (default: 1)");
+
 /* probing devices from the AMBA bus */
 
 static struct resource *get_amba_resource(struct vfio_platform_device *vdev,
@@ -68,6 +72,7 @@ static int vfio_amba_probe(struct amba_device *adev, const struct amba_id *id)
 	vdev->get_resource = get_amba_resource;
 	vdev->get_irq = get_amba_irq;
 	vdev->parent_module = THIS_MODULE;
+	vdev->reset_required = reset_required;
 
 	ret = vfio_platform_probe_common(vdev, &adev->dev);
 	if (ret) {
diff --git a/drivers/vfio/platform/vfio_platform.c b/drivers/vfio/platform/vfio_platform.c
index b1cc3a7..ef89146 100644
--- a/drivers/vfio/platform/vfio_platform.c
+++ b/drivers/vfio/platform/vfio_platform.c
@@ -23,6 +23,10 @@
 #define DRIVER_AUTHOR   "Antonios Motakis <a.motakis@virtualopensystems.com>"
 #define DRIVER_DESC     "VFIO for platform devices - User Level meta-driver"
 
+static bool reset_required = true;
+module_param(reset_required, bool, 0644);
+MODULE_PARM_DESC(reset_required, "override reset requirement (default: 1)");
+
 /* probing devices from the linux platform bus */
 
 static struct resource *get_platform_resource(struct vfio_platform_device *vdev,
@@ -66,6 +70,7 @@ static int vfio_platform_probe(struct platform_device *pdev)
 	vdev->get_resource = get_platform_resource;
 	vdev->get_irq = get_platform_irq;
 	vdev->parent_module = THIS_MODULE;
+	vdev->reset_required = reset_required;
 
 	ret = vfio_platform_probe_common(vdev, &pdev->dev);
 	if (ret)
diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index 0ea8c26..d84c399 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -128,10 +128,10 @@ static bool vfio_platform_has_reset(struct vfio_platform_device *vdev)
 	return vdev->of_reset ? true : false;
 }
 
-static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
+static int vfio_platform_get_reset(struct vfio_platform_device *vdev)
 {
 	if (vdev->acpihid)
-		return;
+		return vfio_platform_acpi_has_reset(vdev) ? 0 : -ENOENT;
 
 	vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
 						    &vdev->reset_module);
@@ -140,6 +140,8 @@ static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
 		vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
 							&vdev->reset_module);
 	}
+
+	return vdev->of_reset ? 0 : -ENOENT;
 }
 
 static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
@@ -670,16 +672,22 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
 	}
 
 	ret = vfio_add_group_dev(dev, &vfio_platform_ops, vdev);
-	if (ret) {
-		iommu_group_put(group);
-		return ret;
-	}
+	if (ret)
+		goto out;
 
-	vfio_platform_get_reset(vdev);
+	ret = vfio_platform_get_reset(vdev);
+	if (ret && vdev->reset_required) {
+		pr_err("vfio: no reset function found for device %s\n",
+		       vdev->name);
+		goto out;
+	}
 
 	mutex_init(&vdev->igate);
 
 	return 0;
+out:
+	iommu_group_put(group);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(vfio_platform_probe_common);
 
diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
index ba9e4f8..68fbc00 100644
--- a/drivers/vfio/platform/vfio_platform_private.h
+++ b/drivers/vfio/platform/vfio_platform_private.h
@@ -50,6 +50,7 @@ struct vfio_platform_region {
 };
 
 struct vfio_platform_device {
+	bool				reset_required;
 	struct vfio_platform_region	*regions;
 	u32				num_regions;
 	struct vfio_platform_irq	*irqs;
-- 
1.8.2.1

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#1423778 — Re: [PATCH V7 7/9] vfio, platform: make reset driver a requirement by default

FromAuger Eric <eric.auger@redhat.com>
Date2016-06-16 10:20 +0200
SubjectRe: [PATCH V7 7/9] vfio, platform: make reset driver a requirement by default
Message-ID<rKAGR-5Qj-7@gated-at.bofh.it>
In reply to#1420438
Hi Sinan,

On 13/06/2016 06:26, Sinan Kaya wrote:
> The code was allowing platform devices to be used without a supporting
> VFIO reset driver. The hardware can be left in some inconsistent state
> after a guest machine abort.
> 
> The reset driver will put the hardware back to safe state and disable
> interrupts before returning the control back to the host machine.
> 
> Adding a new reset_required kernel module option to AMBA and platform
> VFIO drivers with a default value of true.
> 
> New requirements are:
> 1. A reset function needs to be implemented by the corresponding driver
> via DT/ACPI.
> 2. The reset function needs to be discovered via DT/ACPI.
> 
> The probe of the driver will fail if any of the above conditions are
> not satisfied.
> 
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> Reviewed-by: Eric Auger <eric.auger@redhat.com>
> ---
>  drivers/vfio/platform/vfio_amba.c             |  5 +++++
>  drivers/vfio/platform/vfio_platform.c         |  5 +++++
>  drivers/vfio/platform/vfio_platform_common.c  | 22 +++++++++++++++-------
>  drivers/vfio/platform/vfio_platform_private.h |  1 +
>  4 files changed, 26 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/vfio/platform/vfio_amba.c b/drivers/vfio/platform/vfio_amba.c
> index a66479b..7585902 100644
> --- a/drivers/vfio/platform/vfio_amba.c
> +++ b/drivers/vfio/platform/vfio_amba.c
> @@ -23,6 +23,10 @@
>  #define DRIVER_AUTHOR   "Antonios Motakis <a.motakis@virtualopensystems.com>"
>  #define DRIVER_DESC     "VFIO for AMBA devices - User Level meta-driver"
>  
> +static bool reset_required = true;
> +module_param(reset_required, bool, 0644);
> +MODULE_PARM_DESC(reset_required, "override reset requirement (default: 1)");
> +
>  /* probing devices from the AMBA bus */
>  
>  static struct resource *get_amba_resource(struct vfio_platform_device *vdev,
> @@ -68,6 +72,7 @@ static int vfio_amba_probe(struct amba_device *adev, const struct amba_id *id)
>  	vdev->get_resource = get_amba_resource;
>  	vdev->get_irq = get_amba_irq;
>  	vdev->parent_module = THIS_MODULE;
> +	vdev->reset_required = reset_required;
>  
>  	ret = vfio_platform_probe_common(vdev, &adev->dev);
>  	if (ret) {
> diff --git a/drivers/vfio/platform/vfio_platform.c b/drivers/vfio/platform/vfio_platform.c
> index b1cc3a7..ef89146 100644
> --- a/drivers/vfio/platform/vfio_platform.c
> +++ b/drivers/vfio/platform/vfio_platform.c
> @@ -23,6 +23,10 @@
>  #define DRIVER_AUTHOR   "Antonios Motakis <a.motakis@virtualopensystems.com>"
>  #define DRIVER_DESC     "VFIO for platform devices - User Level meta-driver"
>  
> +static bool reset_required = true;
> +module_param(reset_required, bool, 0644);
> +MODULE_PARM_DESC(reset_required, "override reset requirement (default: 1)");
> +
>  /* probing devices from the linux platform bus */
>  
>  static struct resource *get_platform_resource(struct vfio_platform_device *vdev,
> @@ -66,6 +70,7 @@ static int vfio_platform_probe(struct platform_device *pdev)
>  	vdev->get_resource = get_platform_resource;
>  	vdev->get_irq = get_platform_irq;
>  	vdev->parent_module = THIS_MODULE;
> +	vdev->reset_required = reset_required;
>  
>  	ret = vfio_platform_probe_common(vdev, &pdev->dev);
>  	if (ret)
> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
> index 0ea8c26..d84c399 100644
> --- a/drivers/vfio/platform/vfio_platform_common.c
> +++ b/drivers/vfio/platform/vfio_platform_common.c
> @@ -128,10 +128,10 @@ static bool vfio_platform_has_reset(struct vfio_platform_device *vdev)
>  	return vdev->of_reset ? true : false;
>  }
>  
> -static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
> +static int vfio_platform_get_reset(struct vfio_platform_device *vdev)
>  {
>  	if (vdev->acpihid)
> -		return;
> +		return vfio_platform_acpi_has_reset(vdev) ? 0 : -ENOENT;
>  
>  	vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
>  						    &vdev->reset_module);
> @@ -140,6 +140,8 @@ static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
>  		vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
>  							&vdev->reset_module);
>  	}
> +
> +	return vdev->of_reset ? 0 : -ENOENT;
>  }
>  
>  static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
> @@ -670,16 +672,22 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
>  	}
>  
>  	ret = vfio_add_group_dev(dev, &vfio_platform_ops, vdev);
> -	if (ret) {
> -		iommu_group_put(group);
> -		return ret;
> -	}
> +	if (ret)
> +		goto out;
>  
> -	vfio_platform_get_reset(vdev);
> +	ret = vfio_platform_get_reset(vdev);
> +	if (ret && vdev->reset_required) {
> +		pr_err("vfio: no reset function found for device %s\n",
> +		       vdev->name);
> +		goto out;
> +	}
Unfortunately this causes a crash when the reset module is not
available. You should do the vfio_add_group_dev at the end. Something
like below.

Best Regards

Eric

---
 drivers/vfio/platform/vfio_platform_common.c | 26
++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/drivers/vfio/platform/vfio_platform_common.c
b/drivers/vfio/platform/vfio_platform_common.c
index d84c399..0928f7d 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -664,6 +664,14 @@ int vfio_platform_probe_common(struct
vfio_platform_device *vdev,
                return ret;

        vdev->device = dev;
+       mutex_init(&vdev->igate);
+
+       ret = vfio_platform_get_reset(vdev);
+       if (ret && vdev->reset_required) {
+               pr_err("vfio: no reset function found for device %s\n",
+                      vdev->name);
+               return ret;
+       }

        group = iommu_group_get(dev);
        if (!group) {
@@ -672,22 +680,12 @@ int vfio_platform_probe_common(struct
vfio_platform_device *vdev,
        }

        ret = vfio_add_group_dev(dev, &vfio_platform_ops, vdev);
-       if (ret)
-               goto out;
-
-       ret = vfio_platform_get_reset(vdev);
-       if (ret && vdev->reset_required) {
-               pr_err("vfio: no reset function found for device %s\n",
-                      vdev->name);
-               goto out;
-       }
-
-       mutex_init(&vdev->igate);
+       if (ret) {
+               iommu_group_put(group);
+               return ret;
+       }

        return 0;
-out:
-       iommu_group_put(group);
-       return ret;
 }
 EXPORT_SYMBOL_GPL(vfio_platform_probe_common);



>  
>  	mutex_init(&vdev->igate);
>  
>  	return 0;
> +out:
> +	iommu_group_put(group);
> +	return ret;
>  }
>  EXPORT_SYMBOL_GPL(vfio_platform_probe_common);
>  
> diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
> index ba9e4f8..68fbc00 100644
> --- a/drivers/vfio/platform/vfio_platform_private.h
> +++ b/drivers/vfio/platform/vfio_platform_private.h
> @@ -50,6 +50,7 @@ struct vfio_platform_region {
>  };
>  
>  struct vfio_platform_device {
> +	bool				reset_required;
>  	struct vfio_platform_region	*regions;
>  	u32				num_regions;
>  	struct vfio_platform_irq	*irqs;
> 

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#1424283 — Re: [PATCH V7 7/9] vfio, platform: make reset driver a requirement by default

FromSinan Kaya <okaya@codeaurora.org>
Date2016-06-16 19:10 +0200
SubjectRe: [PATCH V7 7/9] vfio, platform: make reset driver a requirement by default
Message-ID<rKIXL-2Gg-3@gated-at.bofh.it>
In reply to#1423778
On 6/16/2016 4:15 AM, Auger Eric wrote:

> Unfortunately this causes a crash when the reset module is not
> available. You should do the vfio_add_group_dev at the end. Something
> like below.
> 

Thanks for testing. I'll post v8 with this change. 


> Best Regards
> 
> Eric
> 
> ---
>  drivers/vfio/platform/vfio_platform_common.c | 26
> ++++++++++++--------------
>  1 file changed, 12 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/vfio/platform/vfio_platform_common.c
> b/drivers/vfio/platform/vfio_platform_common.c
> index d84c399..0928f7d 100644
> --- a/drivers/vfio/platform/vfio_platform_common.c
> +++ b/drivers/vfio/platform/vfio_platform_common.c
> @@ -664,6 +664,14 @@ int vfio_platform_probe_common(struct
> vfio_platform_device *vdev,
>                 return ret;
> 
>         vdev->device = dev;
> +       mutex_init(&vdev->igate);
> +
> +       ret = vfio_platform_get_reset(vdev);
> +       if (ret && vdev->reset_required) {
> +               pr_err("vfio: no reset function found for device %s\n",
> +                      vdev->name);
> +               return ret;
> +       }
> 
>         group = iommu_group_get(dev);
>         if (!group) {
> @@ -672,22 +680,12 @@ int vfio_platform_probe_common(struct
> vfio_platform_device *vdev,
>         }
> 
>         ret = vfio_add_group_dev(dev, &vfio_platform_ops, vdev);
> -       if (ret)
> -               goto out;
> -
> -       ret = vfio_platform_get_reset(vdev);
> -       if (ret && vdev->reset_required) {
> -               pr_err("vfio: no reset function found for device %s\n",
> -                      vdev->name);
> -               goto out;
> -       }
> -
> -       mutex_init(&vdev->igate);
> +       if (ret) {
> +               iommu_group_put(group);
> +               return ret;
> +       }
> 
>         return 0;
> -out:
> -       iommu_group_put(group);
> -       return ret;
>  }
>  EXPORT_SYMBOL_GPL(vfio_platform_probe_common);
> 
> 
> 
>>  
>>  	mutex_init(&vdev->igate);
>>  
>>  	return 0;
>> +out:
>> +	iommu_group_put(group);
>> +	return ret;
>>  }
>>  EXPORT_SYMBOL_GPL(vfio_platform_probe_common);
>>  
>> diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
>> index ba9e4f8..68fbc00 100644
>> --- a/drivers/vfio/platform/vfio_platform_private.h
>> +++ b/drivers/vfio/platform/vfio_platform_private.h
>> @@ -50,6 +50,7 @@ struct vfio_platform_region {
>>  };
>>  
>>  struct vfio_platform_device {
>> +	bool				reset_required;
>>  	struct vfio_platform_region	*regions;
>>  	u32				num_regions;
>>  	struct vfio_platform_irq	*irqs;
>>


-- 
Sinan Kaya
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project

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