[PATCH V7 1/9] vfio: platform: rename reset function

[PATCH V7 1/9] vfio: platform: rename reset function

[Sinan Kaya]

Renaming the reset function to of_reset as it is only used
by the device tree based platforms.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Reviewed-by: Eric Auger <eric.auger@linaro.org>
---
 drivers/vfio/platform/vfio_platform_common.c  | 30 +++++++++++++--------------
 drivers/vfio/platform/vfio_platform_private.h |  6 +++---
 2 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index e65b142..08fd7c2 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -41,7 +41,7 @@ static vfio_platform_reset_fn_t vfio_platform_lookup_reset(const char *compat,
 		if (!strcmp(iter->compat, compat) &&
 			try_module_get(iter->owner)) {
 			*module = iter->owner;
-			reset_fn = iter->reset;
+			reset_fn = iter->of_reset;
 			break;
 		}
 	}
@@ -51,18 +51,18 @@ static vfio_platform_reset_fn_t vfio_platform_lookup_reset(const char *compat,
 
 static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
 {
-	vdev->reset = vfio_platform_lookup_reset(vdev->compat,
-						&vdev->reset_module);
-	if (!vdev->reset) {
+	vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
+						    &vdev->reset_module);
+	if (!vdev->of_reset) {
 		request_module("vfio-reset:%s", vdev->compat);
-		vdev->reset = vfio_platform_lookup_reset(vdev->compat,
-							 &vdev->reset_module);
+		vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
+							&vdev->reset_module);
 	}
 }
 
 static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
 {
-	if (vdev->reset)
+	if (vdev->of_reset)
 		module_put(vdev->reset_module);
 }
 
@@ -141,9 +141,9 @@ static void vfio_platform_release(void *device_data)
 	mutex_lock(&driver_lock);
 
 	if (!(--vdev->refcnt)) {
-		if (vdev->reset) {
+		if (vdev->of_reset) {
 			dev_info(vdev->device, "reset\n");
-			vdev->reset(vdev);
+			vdev->of_reset(vdev);
 		} else {
 			dev_warn(vdev->device, "no reset function found!\n");
 		}
@@ -175,9 +175,9 @@ static int vfio_platform_open(void *device_data)
 		if (ret)
 			goto err_irq;
 
-		if (vdev->reset) {
+		if (vdev->of_reset) {
 			dev_info(vdev->device, "reset\n");
-			vdev->reset(vdev);
+			vdev->of_reset(vdev);
 		} else {
 			dev_warn(vdev->device, "no reset function found!\n");
 		}
@@ -213,7 +213,7 @@ static long vfio_platform_ioctl(void *device_data,
 		if (info.argsz < minsz)
 			return -EINVAL;
 
-		if (vdev->reset)
+		if (vdev->of_reset)
 			vdev->flags |= VFIO_DEVICE_FLAGS_RESET;
 		info.flags = vdev->flags;
 		info.num_regions = vdev->num_regions;
@@ -312,8 +312,8 @@ static long vfio_platform_ioctl(void *device_data,
 		return ret;
 
 	} else if (cmd == VFIO_DEVICE_RESET) {
-		if (vdev->reset)
-			return vdev->reset(vdev);
+		if (vdev->of_reset)
+			return vdev->of_reset(vdev);
 		else
 			return -EINVAL;
 	}
@@ -611,7 +611,7 @@ void vfio_platform_unregister_reset(const char *compat,
 
 	mutex_lock(&driver_lock);
 	list_for_each_entry_safe(iter, temp, &reset_list, link) {
-		if (!strcmp(iter->compat, compat) && (iter->reset == fn)) {
+		if (!strcmp(iter->compat, compat) && (iter->of_reset == fn)) {
 			list_del(&iter->link);
 			break;
 		}
diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
index 42816dd..71ed7d1 100644
--- a/drivers/vfio/platform/vfio_platform_private.h
+++ b/drivers/vfio/platform/vfio_platform_private.h
@@ -71,7 +71,7 @@ struct vfio_platform_device {
 	struct resource*
 		(*get_resource)(struct vfio_platform_device *vdev, int i);
 	int	(*get_irq)(struct vfio_platform_device *vdev, int i);
-	int	(*reset)(struct vfio_platform_device *vdev);
+	int	(*of_reset)(struct vfio_platform_device *vdev);
 };
 
 typedef int (*vfio_platform_reset_fn_t)(struct vfio_platform_device *vdev);
@@ -80,7 +80,7 @@ struct vfio_platform_reset_node {
 	struct list_head link;
 	char *compat;
 	struct module *owner;
-	vfio_platform_reset_fn_t reset;
+	vfio_platform_reset_fn_t of_reset;
 };
 
 extern int vfio_platform_probe_common(struct vfio_platform_device *vdev,
@@ -103,7 +103,7 @@ extern void vfio_platform_unregister_reset(const char *compat,
 static struct vfio_platform_reset_node __reset ## _node = {	\
 	.owner = THIS_MODULE,					\
 	.compat = __compat,					\
-	.reset = __reset,					\
+	.of_reset = __reset,					\
 };								\
 __vfio_platform_register_reset(&__reset ## _node)
 
-- 
1.8.2.1

[PATCH V7 2/9] vfio: platform: move reset call to a common function

[Sinan Kaya]

The reset call sequence seems to replicate itself multiple times
across the file. Grouping them together for maintenance reasons.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Reviewed-by: Eric Auger <eric.auger@linaro.org>
---
 drivers/vfio/platform/vfio_platform_common.c | 30 +++++++++++++---------------
 1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index 08fd7c2..3e2a7c0 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -134,6 +134,17 @@ static void vfio_platform_regions_cleanup(struct vfio_platform_device *vdev)
 	kfree(vdev->regions);
 }
 
+static int vfio_platform_call_reset(struct vfio_platform_device *vdev)
+{
+	if (vdev->of_reset) {
+		dev_info(vdev->device, "reset\n");
+		return vdev->of_reset(vdev);
+	}
+
+	dev_warn(vdev->device, "no reset function found!\n");
+	return -EINVAL;
+}
+
 static void vfio_platform_release(void *device_data)
 {
 	struct vfio_platform_device *vdev = device_data;
@@ -141,12 +152,7 @@ static void vfio_platform_release(void *device_data)
 	mutex_lock(&driver_lock);
 
 	if (!(--vdev->refcnt)) {
-		if (vdev->of_reset) {
-			dev_info(vdev->device, "reset\n");
-			vdev->of_reset(vdev);
-		} else {
-			dev_warn(vdev->device, "no reset function found!\n");
-		}
+		vfio_platform_call_reset(vdev);
 		vfio_platform_regions_cleanup(vdev);
 		vfio_platform_irq_cleanup(vdev);
 	}
@@ -175,12 +181,7 @@ static int vfio_platform_open(void *device_data)
 		if (ret)
 			goto err_irq;
 
-		if (vdev->of_reset) {
-			dev_info(vdev->device, "reset\n");
-			vdev->of_reset(vdev);
-		} else {
-			dev_warn(vdev->device, "no reset function found!\n");
-		}
+		vfio_platform_call_reset(vdev);
 	}
 
 	vdev->refcnt++;
@@ -312,10 +313,7 @@ static long vfio_platform_ioctl(void *device_data,
 		return ret;
 
 	} else if (cmd == VFIO_DEVICE_RESET) {
-		if (vdev->of_reset)
-			return vdev->of_reset(vdev);
-		else
-			return -EINVAL;
+		return vfio_platform_call_reset(vdev);
 	}
 
 	return -ENOTTY;
-- 
1.8.2.1

[PATCH V7 3/9] vfio: platform: determine reset capability

[Sinan Kaya]

Creating a new function to determine if this driver supports reset
function or not. This is an attempt to abstract device tree calls
from the rest of the code.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Reviewed-by: Eric Auger <eric.auger@linaro.org>
---
 drivers/vfio/platform/vfio_platform_common.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index 3e2a7c0..6be92c3 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -49,6 +49,11 @@ static vfio_platform_reset_fn_t vfio_platform_lookup_reset(const char *compat,
 	return reset_fn;
 }
 
+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)
 {
 	vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
@@ -214,7 +219,7 @@ static long vfio_platform_ioctl(void *device_data,
 		if (info.argsz < minsz)
 			return -EINVAL;
 
-		if (vdev->of_reset)
+		if (vfio_platform_has_reset(vdev))
 			vdev->flags |= VFIO_DEVICE_FLAGS_RESET;
 		info.flags = vdev->flags;
 		info.num_regions = vdev->num_regions;
-- 
1.8.2.1

[PATCH V7 4/9] vfio: platform: add support for ACPI probe

[Sinan Kaya]

The code is using the compatible DT string to associate a reset driver
with the actual device itself. The compatible string does not exist on
ACPI based systems. HID is the unique identifier for a device driver
instead.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
---
 drivers/vfio/platform/vfio_platform_common.c  | 57 ++++++++++++++++++++++++---
 drivers/vfio/platform/vfio_platform_private.h |  1 +
 2 files changed, 53 insertions(+), 5 deletions(-)

diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index 6be92c3..fbf4565 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -13,6 +13,7 @@
  */
 
 #include <linux/device.h>
+#include <linux/acpi.h>
 #include <linux/iommu.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
@@ -49,6 +50,37 @@ static vfio_platform_reset_fn_t vfio_platform_lookup_reset(const char *compat,
 	return reset_fn;
 }
 
+#ifdef CONFIG_ACPI
+static int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
+				    struct device *dev)
+{
+	struct acpi_device *adev = ACPI_COMPANION(dev);
+
+	if (acpi_disabled)
+		return -ENODEV;
+
+	if (!adev) {
+		pr_err("VFIO: ACPI companion device not found for %s\n",
+			vdev->name);
+		return -ENODEV;
+	}
+
+	vdev->acpihid = acpi_device_hid(adev);
+	if (!vdev->acpihid) {
+		pr_err("VFIO: cannot find ACPI HID for %s\n",
+		       vdev->name);
+		return -ENODEV;
+	}
+	return 0;
+}
+#else
+static inline int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
+					   struct device *dev)
+{
+	return -ENOENT;
+}
+#endif
+
 static bool vfio_platform_has_reset(struct vfio_platform_device *vdev)
 {
 	return vdev->of_reset ? true : false;
@@ -547,6 +579,20 @@ static const struct vfio_device_ops vfio_platform_ops = {
 	.mmap		= vfio_platform_mmap,
 };
 
+int vfio_platform_of_probe(struct vfio_platform_device *vdev,
+			   struct device *dev)
+{
+	int ret;
+
+	ret = device_property_read_string(dev, "compatible",
+					  &vdev->compat);
+	if (ret)
+		pr_err("VFIO: cannot retrieve compat for %s\n",
+			vdev->name);
+
+	return ret;
+}
+
 int vfio_platform_probe_common(struct vfio_platform_device *vdev,
 			       struct device *dev)
 {
@@ -556,11 +602,12 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
 	if (!vdev)
 		return -EINVAL;
 
-	ret = device_property_read_string(dev, "compatible", &vdev->compat);
-	if (ret) {
-		pr_err("VFIO: cannot retrieve compat for %s\n", vdev->name);
-		return -EINVAL;
-	}
+	ret = vfio_platform_acpi_probe(vdev, dev);
+	if (ret)
+		ret = vfio_platform_of_probe(vdev, dev);
+
+	if (ret)
+		return ret;
 
 	vdev->device = dev;
 
diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
index 71ed7d1..ba9e4f8 100644
--- a/drivers/vfio/platform/vfio_platform_private.h
+++ b/drivers/vfio/platform/vfio_platform_private.h
@@ -58,6 +58,7 @@ struct vfio_platform_device {
 	struct mutex			igate;
 	struct module			*parent_module;
 	const char			*compat;
+	const char			*acpihid;
 	struct module			*reset_module;
 	struct device			*device;
 
-- 
1.8.2.1

[PATCH V7 5/9] vfio: platform: add extra debug info argument to call reset

[Sinan Kaya]

Getting ready to bring out extra debug information to the caller
so that more verbose information can be printed when an error is
observed.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/vfio/platform/vfio_platform_common.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index fbf4565..e7ce2c2 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -171,7 +171,8 @@ static void vfio_platform_regions_cleanup(struct vfio_platform_device *vdev)
 	kfree(vdev->regions);
 }
 
-static int vfio_platform_call_reset(struct vfio_platform_device *vdev)
+static int vfio_platform_call_reset(struct vfio_platform_device *vdev,
+				    const char **extra_dbg)
 {
 	if (vdev->of_reset) {
 		dev_info(vdev->device, "reset\n");
@@ -189,7 +190,7 @@ static void vfio_platform_release(void *device_data)
 	mutex_lock(&driver_lock);
 
 	if (!(--vdev->refcnt)) {
-		vfio_platform_call_reset(vdev);
+		vfio_platform_call_reset(vdev, NULL);
 		vfio_platform_regions_cleanup(vdev);
 		vfio_platform_irq_cleanup(vdev);
 	}
@@ -218,7 +219,7 @@ static int vfio_platform_open(void *device_data)
 		if (ret)
 			goto err_irq;
 
-		vfio_platform_call_reset(vdev);
+		vfio_platform_call_reset(vdev, NULL);
 	}
 
 	vdev->refcnt++;
@@ -350,7 +351,7 @@ static long vfio_platform_ioctl(void *device_data,
 		return ret;
 
 	} else if (cmd == VFIO_DEVICE_RESET) {
-		return vfio_platform_call_reset(vdev);
+		return vfio_platform_call_reset(vdev, NULL);
 	}
 
 	return -ENOTTY;
-- 
1.8.2.1

[PATCH V7 6/9] vfio: platform: call _RST method when using ACPI

[Sinan Kaya]

The device tree code checks for the presence of a reset driver and calls
the of_reset function pointer by looking up the reset driver as a module.

ACPI defines _RST method to perform device level reset. After the _RST
method is executed, the OS can resume using the device. _RST method is
expected to stop DMA transfers and IRQs.

This patch introduces two functions as vfio_platform_acpi_has_reset and
vfio_platform_acpi_call_reset. The has reset method is used to declare
reset capability via the ioctl flag VFIO_DEVICE_FLAGS_RESET. The call
reset function is used to execute the _RST ACPI method.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Reviewed-by: Eric Auger <eric.auger@linaro.org>
---
 drivers/vfio/platform/vfio_platform_common.c | 51 ++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index e7ce2c2..0ea8c26 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -73,21 +73,66 @@ static int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
 	}
 	return 0;
 }
+
+static int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev,
+					 const char **extra_dbg)
+{
+	struct device *dev = vdev->device;
+	acpi_handle handle = ACPI_HANDLE(dev);
+	acpi_status acpi_ret;
+	unsigned long long val;
+
+	acpi_ret = acpi_evaluate_integer(handle, "_RST", NULL, &val);
+	if (ACPI_FAILURE(acpi_ret)) {
+		if (extra_dbg)
+			*extra_dbg = acpi_format_exception(acpi_ret);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)
+{
+	struct device *dev = vdev->device;
+	acpi_handle handle = ACPI_HANDLE(dev);
+
+	return acpi_has_method(handle, "_RST");
+}
 #else
 static inline int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
 					   struct device *dev)
 {
 	return -ENOENT;
 }
+
+static inline
+int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev,
+				  const char **extra_dbg)
+{
+	return -ENOENT;
+}
+
+static inline
+bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)
+{
+	return false;
+}
 #endif
 
 static bool vfio_platform_has_reset(struct vfio_platform_device *vdev)
 {
+	if (vdev->acpihid)
+		return vfio_platform_acpi_has_reset(vdev);
+
 	return vdev->of_reset ? true : false;
 }
 
 static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
 {
+	if (vdev->acpihid)
+		return;
+
 	vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
 						    &vdev->reset_module);
 	if (!vdev->of_reset) {
@@ -99,6 +144,9 @@ static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
 
 static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
 {
+	if (vdev->acpihid)
+		return;
+
 	if (vdev->of_reset)
 		module_put(vdev->reset_module);
 }
@@ -177,6 +225,9 @@ static int vfio_platform_call_reset(struct vfio_platform_device *vdev,
 	if (vdev->of_reset) {
 		dev_info(vdev->device, "reset\n");
 		return vdev->of_reset(vdev);
+	} else if (vdev->acpihid) {
+		dev_info(vdev->device, "reset\n");
+		return vfio_platform_acpi_call_reset(vdev, extra_dbg);
 	}
 
 	dev_warn(vdev->device, "no reset function found!\n");
-- 
1.8.2.1

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

[Sinan Kaya]

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

[PATCH V7 8/9] vfio: platform: check reset call return code during open

[Sinan Kaya]

Open call is ignoring the return code from reset call and can
potentially continue even though reset call failed.

If reset_required module parameter is set, this patch is going
to validate the return code and will abort open if reset fails.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/vfio/platform/vfio_platform_common.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index d84c399..d3141e7 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -264,6 +264,8 @@ static int vfio_platform_open(void *device_data)
 	mutex_lock(&driver_lock);
 
 	if (!vdev->refcnt) {
+		const char *extra_dbg = NULL;
+
 		ret = vfio_platform_regions_init(vdev);
 		if (ret)
 			goto err_reg;
@@ -272,7 +274,12 @@ static int vfio_platform_open(void *device_data)
 		if (ret)
 			goto err_irq;
 
-		vfio_platform_call_reset(vdev, NULL);
+		ret = vfio_platform_call_reset(vdev, &extra_dbg);
+		if (ret && vdev->reset_required) {
+			dev_warn(vdev->device, "reset driver is required and reset call failed in open (%d) %s\n",
+				 ret, extra_dbg ? extra_dbg : "");
+			goto err_rst;
+		}
 	}
 
 	vdev->refcnt++;
@@ -280,6 +287,8 @@ static int vfio_platform_open(void *device_data)
 	mutex_unlock(&driver_lock);
 	return 0;
 
+err_rst:
+	vfio_platform_irq_cleanup(vdev);
 err_irq:
 	vfio_platform_regions_cleanup(vdev);
 err_reg:
-- 
1.8.2.1

[PATCH V7 9/9] vfio: platform: check reset call return code during release

[Sinan Kaya]

Release call is ignoring the return code from reset call and can
potentially continue even though reset call failed.

If reset_required module parameter is set, this patch is going
to validate the return code and will cause stack dump with
WARN_ON and warn the user of failure.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
---
 drivers/vfio/platform/vfio_platform_common.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index d3141e7..5035c3f 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -243,7 +243,15 @@ static void vfio_platform_release(void *device_data)
 	mutex_lock(&driver_lock);
 
 	if (!(--vdev->refcnt)) {
-		vfio_platform_call_reset(vdev, NULL);
+		const char *extra_dbg = NULL;
+		int ret;
+
+		ret = vfio_platform_call_reset(vdev, &extra_dbg);
+		if (ret && vdev->reset_required) {
+			dev_warn(vdev->device, "reset driver is required and reset call failed in release (%d) %s\n",
+				 ret, extra_dbg ? extra_dbg : "");
+			WARN_ON(1);
+		}
 		vfio_platform_regions_cleanup(vdev);
 		vfio_platform_irq_cleanup(vdev);
 	}
-- 
1.8.2.1

Re: [PATCH V7 8/9] vfio: platform: check reset call return code during open

[Auger Eric]

Hi Sinan,

On 13/06/2016 06:26, Sinan Kaya wrote:
> Open call is ignoring the return code from reset call and can
> potentially continue even though reset call failed.
> 
> If reset_required module parameter is set, this patch is going
> to validate the return code and will abort open if reset fails.
> 
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> ---
>  drivers/vfio/platform/vfio_platform_common.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
> index d84c399..d3141e7 100644
> --- a/drivers/vfio/platform/vfio_platform_common.c
> +++ b/drivers/vfio/platform/vfio_platform_common.c
> @@ -264,6 +264,8 @@ static int vfio_platform_open(void *device_data)
>  	mutex_lock(&driver_lock);
>  
>  	if (!vdev->refcnt) {
> +		const char *extra_dbg = NULL;
> +
>  		ret = vfio_platform_regions_init(vdev);
>  		if (ret)
>  			goto err_reg;
> @@ -272,7 +274,12 @@ static int vfio_platform_open(void *device_data)
>  		if (ret)
>  			goto err_irq;
>  
> -		vfio_platform_call_reset(vdev, NULL);
> +		ret = vfio_platform_call_reset(vdev, &extra_dbg);
> +		if (ret && vdev->reset_required) {
> +			dev_warn(vdev->device, "reset driver is required and reset call failed in open (%d) %s\n",
> +				 ret, extra_dbg ? extra_dbg : "");
> +			goto err_rst;
> +		}
>  	}
>  
>  	vdev->refcnt++;
> @@ -280,6 +287,8 @@ static int vfio_platform_open(void *device_data)
>  	mutex_unlock(&driver_lock);
>  	return 0;
>  
> +err_rst:
> +	vfio_platform_irq_cleanup(vdev);
>  err_irq:
>  	vfio_platform_regions_cleanup(vdev);
>  err_reg:
> 

Reviewed-by: Eric Auger <eric.auger@redhat.com>

Thanks

Eric

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

[Auger Eric]

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;
> 

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

[Sinan Kaya]

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

Re: [PATCH V7 6/9] vfio: platform: call _RST method when using ACPI

[Alex Williamson]

On Mon, 13 Jun 2016 00:26:38 -0400
Sinan Kaya <okaya@codeaurora.org> wrote:

> The device tree code checks for the presence of a reset driver and calls
> the of_reset function pointer by looking up the reset driver as a module.
> 
> ACPI defines _RST method to perform device level reset. After the _RST
> method is executed, the OS can resume using the device. _RST method is
> expected to stop DMA transfers and IRQs.
> 
> This patch introduces two functions as vfio_platform_acpi_has_reset and
> vfio_platform_acpi_call_reset. The has reset method is used to declare
> reset capability via the ioctl flag VFIO_DEVICE_FLAGS_RESET. The call
> reset function is used to execute the _RST ACPI method.
> 
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> Reviewed-by: Eric Auger <eric.auger@linaro.org>
> ---
>  drivers/vfio/platform/vfio_platform_common.c | 51 ++++++++++++++++++++++++++++
>  1 file changed, 51 insertions(+)
> 
> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
> index e7ce2c2..0ea8c26 100644
> --- a/drivers/vfio/platform/vfio_platform_common.c
> +++ b/drivers/vfio/platform/vfio_platform_common.c
> @@ -73,21 +73,66 @@ static int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
>  	}
>  	return 0;
>  }
> +
> +static int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev,
> +					 const char **extra_dbg)
> +{
> +	struct device *dev = vdev->device;
> +	acpi_handle handle = ACPI_HANDLE(dev);
> +	acpi_status acpi_ret;
> +	unsigned long long val;
> +
> +	acpi_ret = acpi_evaluate_integer(handle, "_RST", NULL, &val);
> +	if (ACPI_FAILURE(acpi_ret)) {
> +		if (extra_dbg)
> +			*extra_dbg = acpi_format_exception(acpi_ret);
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)
> +{
> +	struct device *dev = vdev->device;
> +	acpi_handle handle = ACPI_HANDLE(dev);
> +
> +	return acpi_has_method(handle, "_RST");
> +}
>  #else
>  static inline int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
>  					   struct device *dev)
>  {
>  	return -ENOENT;
>  }
> +
> +static inline
> +int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev,
> +				  const char **extra_dbg)
> +{
> +	return -ENOENT;
> +}
> +
> +static inline
> +bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)
> +{
> +	return false;
> +}
>  #endif
>  
>  static bool vfio_platform_has_reset(struct vfio_platform_device *vdev)
>  {
> +	if (vdev->acpihid)
> +		return vfio_platform_acpi_has_reset(vdev);
> +
>  	return vdev->of_reset ? true : false;
>  }
>  
>  static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
>  {
> +	if (vdev->acpihid)
> +		return;
> +
>  	vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
>  						    &vdev->reset_module);
>  	if (!vdev->of_reset) {
> @@ -99,6 +144,9 @@ static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
>  
>  static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
>  {
> +	if (vdev->acpihid)
> +		return;
> +
>  	if (vdev->of_reset)
>  		module_put(vdev->reset_module);
>  }
> @@ -177,6 +225,9 @@ static int vfio_platform_call_reset(struct vfio_platform_device *vdev,
>  	if (vdev->of_reset) {
>  		dev_info(vdev->device, "reset\n");
>  		return vdev->of_reset(vdev);
> +	} else if (vdev->acpihid) {
> +		dev_info(vdev->device, "reset\n");
> +		return vfio_platform_acpi_call_reset(vdev, extra_dbg);


nit, all the cases until this one prioritize ACPI over DT, here we have
the opposite.  Granted we should never have of_reset set when acpihid
is set.  A macro like

#define vfio_platform_is_acpi(vdev) (vdev->acpihid != NULL)

might be useful.


>  	}
>  
>  	dev_warn(vdev->device, "no reset function found!\n");

Re: [PATCH V7 6/9] vfio: platform: call _RST method when using ACPI

[Alex Williamson]

On Thu, 23 Jun 2016 12:59:48 -0600
Alex Williamson <alex.williamson@redhat.com> wrote:

> On Mon, 13 Jun 2016 00:26:38 -0400
> Sinan Kaya <okaya@codeaurora.org> wrote:
> 
> > The device tree code checks for the presence of a reset driver and calls
> > the of_reset function pointer by looking up the reset driver as a module.
> > 
> > ACPI defines _RST method to perform device level reset. After the _RST
> > method is executed, the OS can resume using the device. _RST method is
> > expected to stop DMA transfers and IRQs.
> > 
> > This patch introduces two functions as vfio_platform_acpi_has_reset and
> > vfio_platform_acpi_call_reset. The has reset method is used to declare
> > reset capability via the ioctl flag VFIO_DEVICE_FLAGS_RESET. The call
> > reset function is used to execute the _RST ACPI method.
> > 
> > Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> > Reviewed-by: Eric Auger <eric.auger@linaro.org>
> > ---
> >  drivers/vfio/platform/vfio_platform_common.c | 51 ++++++++++++++++++++++++++++
> >  1 file changed, 51 insertions(+)
> > 
> > diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
> > index e7ce2c2..0ea8c26 100644
> > --- a/drivers/vfio/platform/vfio_platform_common.c
> > +++ b/drivers/vfio/platform/vfio_platform_common.c
> > @@ -73,21 +73,66 @@ static int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
> >  	}
> >  	return 0;
> >  }
> > +
> > +static int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev,
> > +					 const char **extra_dbg)
> > +{
> > +	struct device *dev = vdev->device;
> > +	acpi_handle handle = ACPI_HANDLE(dev);
> > +	acpi_status acpi_ret;
> > +	unsigned long long val;
> > +
> > +	acpi_ret = acpi_evaluate_integer(handle, "_RST", NULL, &val);
> > +	if (ACPI_FAILURE(acpi_ret)) {
> > +		if (extra_dbg)
> > +			*extra_dbg = acpi_format_exception(acpi_ret);
> > +		return -EINVAL;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)
> > +{
> > +	struct device *dev = vdev->device;
> > +	acpi_handle handle = ACPI_HANDLE(dev);
> > +
> > +	return acpi_has_method(handle, "_RST");
> > +}
> >  #else
> >  static inline int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
> >  					   struct device *dev)
> >  {
> >  	return -ENOENT;
> >  }
> > +
> > +static inline
> > +int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev,
> > +				  const char **extra_dbg)
> > +{
> > +	return -ENOENT;
> > +}
> > +
> > +static inline
> > +bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)
> > +{
> > +	return false;
> > +}
> >  #endif
> >  
> >  static bool vfio_platform_has_reset(struct vfio_platform_device *vdev)
> >  {
> > +	if (vdev->acpihid)
> > +		return vfio_platform_acpi_has_reset(vdev);
> > +
> >  	return vdev->of_reset ? true : false;
> >  }
> >  
> >  static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
> >  {
> > +	if (vdev->acpihid)
> > +		return;
> > +
> >  	vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
> >  						    &vdev->reset_module);
> >  	if (!vdev->of_reset) {
> > @@ -99,6 +144,9 @@ static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
> >  
> >  static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
> >  {
> > +	if (vdev->acpihid)
> > +		return;
> > +
> >  	if (vdev->of_reset)
> >  		module_put(vdev->reset_module);
> >  }
> > @@ -177,6 +225,9 @@ static int vfio_platform_call_reset(struct vfio_platform_device *vdev,
> >  	if (vdev->of_reset) {
> >  		dev_info(vdev->device, "reset\n");
> >  		return vdev->of_reset(vdev);
> > +	} else if (vdev->acpihid) {
> > +		dev_info(vdev->device, "reset\n");
> > +		return vfio_platform_acpi_call_reset(vdev, extra_dbg);  
> 
> 
> nit, all the cases until this one prioritize ACPI over DT, here we have
> the opposite.  Granted we should never have of_reset set when acpihid
> is set.  A macro like
> 
> #define vfio_platform_is_acpi(vdev) (vdev->acpihid != NULL)
> 
> might be useful.

Oops, I accidentally picked the v7 version to reply to, but the nit
exists in v8 as well.  Thanks,

Alex

Re: [PATCH V7 6/9] vfio: platform: call _RST method when using ACPI

[Sinan Kaya]

On 6/23/2016 3:07 PM, Alex Williamson wrote:
>> might be useful.
> Oops, I accidentally picked the v7 version to reply to, but the nit
> exists in v8 as well.  Thanks,

No problem. I'll work on your comments and post a follow up. 

-- 
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

Re: [PATCH V7 6/9] vfio: platform: call _RST method when using ACPI

[Sinan Kaya]

On 6/23/2016 2:59 PM, Alex Williamson wrote:
> On Mon, 13 Jun 2016 00:26:38 -0400
> Sinan Kaya <okaya@codeaurora.org> wrote:
> 
>> The device tree code checks for the presence of a reset driver and calls
>> the of_reset function pointer by looking up the reset driver as a module.
>>
>> ACPI defines _RST method to perform device level reset. After the _RST
>> method is executed, the OS can resume using the device. _RST method is
>> expected to stop DMA transfers and IRQs.
>>
>> This patch introduces two functions as vfio_platform_acpi_has_reset and
>> vfio_platform_acpi_call_reset. The has reset method is used to declare
>> reset capability via the ioctl flag VFIO_DEVICE_FLAGS_RESET. The call
>> reset function is used to execute the _RST ACPI method.
>>
>> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
>> Reviewed-by: Eric Auger <eric.auger@linaro.org>
>> ---
>>  drivers/vfio/platform/vfio_platform_common.c | 51 ++++++++++++++++++++++++++++
>>  1 file changed, 51 insertions(+)
>>
>> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
>> index e7ce2c2..0ea8c26 100644
>> --- a/drivers/vfio/platform/vfio_platform_common.c
>> +++ b/drivers/vfio/platform/vfio_platform_common.c
>> @@ -73,21 +73,66 @@ static int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
>>  	}
>>  	return 0;
>>  }
>> +
>> +static int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev,
>> +					 const char **extra_dbg)
>> +{
>> +	struct device *dev = vdev->device;
>> +	acpi_handle handle = ACPI_HANDLE(dev);
>> +	acpi_status acpi_ret;
>> +	unsigned long long val;
>> +
>> +	acpi_ret = acpi_evaluate_integer(handle, "_RST", NULL, &val);
>> +	if (ACPI_FAILURE(acpi_ret)) {
>> +		if (extra_dbg)
>> +			*extra_dbg = acpi_format_exception(acpi_ret);
>> +		return -EINVAL;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)
>> +{
>> +	struct device *dev = vdev->device;
>> +	acpi_handle handle = ACPI_HANDLE(dev);
>> +
>> +	return acpi_has_method(handle, "_RST");
>> +}
>>  #else
>>  static inline int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
>>  					   struct device *dev)
>>  {
>>  	return -ENOENT;
>>  }
>> +
>> +static inline
>> +int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev,
>> +				  const char **extra_dbg)
>> +{
>> +	return -ENOENT;
>> +}
>> +
>> +static inline
>> +bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)
>> +{
>> +	return false;
>> +}
>>  #endif
>>  
>>  static bool vfio_platform_has_reset(struct vfio_platform_device *vdev)
>>  {
>> +	if (vdev->acpihid)
>> +		return vfio_platform_acpi_has_reset(vdev);
>> +
>>  	return vdev->of_reset ? true : false;
>>  }
>>  
>>  static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
>>  {
>> +	if (vdev->acpihid)
>> +		return;
>> +
>>  	vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
>>  						    &vdev->reset_module);
>>  	if (!vdev->of_reset) {
>> @@ -99,6 +144,9 @@ static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
>>  
>>  static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
>>  {
>> +	if (vdev->acpihid)
>> +		return;
>> +
>>  	if (vdev->of_reset)
>>  		module_put(vdev->reset_module);
>>  }
>> @@ -177,6 +225,9 @@ static int vfio_platform_call_reset(struct vfio_platform_device *vdev,
>>  	if (vdev->of_reset) {
>>  		dev_info(vdev->device, "reset\n");
>>  		return vdev->of_reset(vdev);
>> +	} else if (vdev->acpihid) {
>> +		dev_info(vdev->device, "reset\n");
>> +		return vfio_platform_acpi_call_reset(vdev, extra_dbg);
> 
> 
> nit, all the cases until this one prioritize ACPI over DT, here we have
> the opposite. 

I'll reorder to be consistent.

> Granted we should never have of_reset set when acpihid
> is set.  A macro like
> 
> #define vfio_platform_is_acpi(vdev) (vdev->acpihid != NULL)
> 
> might be useful.

I like your idea. If you don't mind, I like capitals in macros. 

> 
> 
>>  	}
>>  
>>  	dev_warn(vdev->device, "no reset function found!\n");
> 


-- 
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.

Re: [PATCH V7 6/9] vfio: platform: call _RST method when using ACPI

[Alex Williamson]

On Wed, 13 Jul 2016 15:39:25 -0400
Sinan Kaya <okaya@codeaurora.org> wrote:

> On 6/23/2016 2:59 PM, Alex Williamson wrote:
> > On Mon, 13 Jun 2016 00:26:38 -0400
> > Sinan Kaya <okaya@codeaurora.org> wrote:
> >   
> >> The device tree code checks for the presence of a reset driver and calls
> >> the of_reset function pointer by looking up the reset driver as a module.
> >>
> >> ACPI defines _RST method to perform device level reset. After the _RST
> >> method is executed, the OS can resume using the device. _RST method is
> >> expected to stop DMA transfers and IRQs.
> >>
> >> This patch introduces two functions as vfio_platform_acpi_has_reset and
> >> vfio_platform_acpi_call_reset. The has reset method is used to declare
> >> reset capability via the ioctl flag VFIO_DEVICE_FLAGS_RESET. The call
> >> reset function is used to execute the _RST ACPI method.
> >>
> >> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> >> Reviewed-by: Eric Auger <eric.auger@linaro.org>
> >> ---
> >>  drivers/vfio/platform/vfio_platform_common.c | 51 ++++++++++++++++++++++++++++
> >>  1 file changed, 51 insertions(+)
> >>
> >> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
> >> index e7ce2c2..0ea8c26 100644
> >> --- a/drivers/vfio/platform/vfio_platform_common.c
> >> +++ b/drivers/vfio/platform/vfio_platform_common.c
> >> @@ -73,21 +73,66 @@ static int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
> >>  	}
> >>  	return 0;
> >>  }
> >> +
> >> +static int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev,
> >> +					 const char **extra_dbg)
> >> +{
> >> +	struct device *dev = vdev->device;
> >> +	acpi_handle handle = ACPI_HANDLE(dev);
> >> +	acpi_status acpi_ret;
> >> +	unsigned long long val;
> >> +
> >> +	acpi_ret = acpi_evaluate_integer(handle, "_RST", NULL, &val);
> >> +	if (ACPI_FAILURE(acpi_ret)) {
> >> +		if (extra_dbg)
> >> +			*extra_dbg = acpi_format_exception(acpi_ret);
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)
> >> +{
> >> +	struct device *dev = vdev->device;
> >> +	acpi_handle handle = ACPI_HANDLE(dev);
> >> +
> >> +	return acpi_has_method(handle, "_RST");
> >> +}
> >>  #else
> >>  static inline int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
> >>  					   struct device *dev)
> >>  {
> >>  	return -ENOENT;
> >>  }
> >> +
> >> +static inline
> >> +int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev,
> >> +				  const char **extra_dbg)
> >> +{
> >> +	return -ENOENT;
> >> +}
> >> +
> >> +static inline
> >> +bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)
> >> +{
> >> +	return false;
> >> +}
> >>  #endif
> >>  
> >>  static bool vfio_platform_has_reset(struct vfio_platform_device *vdev)
> >>  {
> >> +	if (vdev->acpihid)
> >> +		return vfio_platform_acpi_has_reset(vdev);
> >> +
> >>  	return vdev->of_reset ? true : false;
> >>  }
> >>  
> >>  static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
> >>  {
> >> +	if (vdev->acpihid)
> >> +		return;
> >> +
> >>  	vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
> >>  						    &vdev->reset_module);
> >>  	if (!vdev->of_reset) {
> >> @@ -99,6 +144,9 @@ static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
> >>  
> >>  static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
> >>  {
> >> +	if (vdev->acpihid)
> >> +		return;
> >> +
> >>  	if (vdev->of_reset)
> >>  		module_put(vdev->reset_module);
> >>  }
> >> @@ -177,6 +225,9 @@ static int vfio_platform_call_reset(struct vfio_platform_device *vdev,
> >>  	if (vdev->of_reset) {
> >>  		dev_info(vdev->device, "reset\n");
> >>  		return vdev->of_reset(vdev);
> >> +	} else if (vdev->acpihid) {
> >> +		dev_info(vdev->device, "reset\n");
> >> +		return vfio_platform_acpi_call_reset(vdev, extra_dbg);  
> > 
> > 
> > nit, all the cases until this one prioritize ACPI over DT, here we have
> > the opposite.   
> 
> I'll reorder to be consistent.
> 
> > Granted we should never have of_reset set when acpihid
> > is set.  A macro like
> > 
> > #define vfio_platform_is_acpi(vdev) (vdev->acpihid != NULL)
> > 
> > might be useful.  
> 
> I like your idea. If you don't mind, I like capitals in macros. 

Sure.  Thanks,

Alex