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SubjectRe: [PATCH v3 05/14] s390: vfio-ap: base implementation of VFIO AP device driver
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On 04/03/2018 06:57 AM, Cornelia Huck wrote:
> On Wed, 14 Mar 2018 14:25:45 -0400
> Tony Krowiak <akrowiak@linux.vnet.ibm.com> wrote:
>
>> Introduces a new AP device driver. This device driver
>> is built on the VFIO mediated device framework. The framework
>> provides sysfs interfaces that facilitate passthrough
>> access by guests to devices installed on the linux host.
>>
>> The VFIO AP device driver will serve two purposes:
>>
>> 1. Provide the interfaces to reserve AP devices for exclusive
>> use by KVM guests. This is accomplished by unbinding the
>> devices to be reserved for guest usage from the default AP
>> device driver and binding them to the VFIO AP device driver.
>>
>> 2. Implements the functions, callbacks and sysfs attribute
>> interfaces required to create one or more VFIO mediated
>> devices each of which will be used to configure the AP
>> matrix for a guest and serve as a file descriptor
>> for facilitating communication between QEMU and the
>> VFIO AP device driver.
>>
>> When the VFIO AP device driver is initialized:
>>
>> * It registers with the AP bus for control of type 10 (CEX4
>> and newer) AP queue devices. The probe and remove callbacks
>> will be provided to support the binding/unbinding of
>> AP queue devices to/from the VFIO AP device driver.
>>
>> * Creates a /sys/devices/vfio-ap/matrix device to hold
>> the APQNs of the AP devices bound to the VFIO
>> AP device driver and serves as the parent of the
>> mediated devices created for each guest.
>>
>> Signed-off-by: Tony Krowiak <akrowiak@linux.vnet.ibm.com>
>> ---
>> MAINTAINERS | 2 +
>> arch/s390/Kconfig | 11 +++
>> drivers/s390/crypto/Makefile | 4 +
>> drivers/s390/crypto/vfio_ap_drv.c | 135 +++++++++++++++++++++++++++++++++
>> drivers/s390/crypto/vfio_ap_private.h | 22 ++++++
>> include/uapi/linux/vfio.h | 2 +
>> 6 files changed, 176 insertions(+), 0 deletions(-)
>> create mode 100644 drivers/s390/crypto/vfio_ap_drv.c
>> create mode 100644 drivers/s390/crypto/vfio_ap_private.h
>>
>> diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
>> new file mode 100644
>> index 0000000..459e595
>> --- /dev/null
>> +++ b/drivers/s390/crypto/vfio_ap_drv.c
>> @@ -0,0 +1,135 @@
>> +/*
>> + * VFIO based AP device driver
>> + *
>> + * Copyright IBM Corp. 2017
> Update to 2018?
Okay, will do.
>
>> + *
>> + * Author(s): Tony Krowiak <akrowiak@linux.vnet.ibm.com>
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/mod_devicetable.h>
>> +#include <linux/slab.h>
>> +
>> +#include "vfio_ap_private.h"
>> +
>> +#define VFIO_AP_ROOT_NAME "vfio_ap"
>> +#define VFIO_AP_DEV_TYPE_NAME "ap_matrix"
>> +#define VFIO_AP_DEV_NAME "matrix"
>> +
>> +MODULE_AUTHOR("IBM Corporation");
>> +MODULE_DESCRIPTION("VFIO AP device driver, Copyright IBM Corp. 2017");
>> +MODULE_LICENSE("GPL v2");
>> +
>> +static struct device *vfio_ap_root_device;
>> +
>> +static struct ap_driver vfio_ap_drv;
>> +
>> +static struct ap_matrix *ap_matrix;
>> +
>> +static struct device_type vfio_ap_dev_type = {
>> + .name = VFIO_AP_DEV_TYPE_NAME,
>> +};
>> +
>> +/* Only type 10 adapters (CEX4 and later) are supported
>> + * by the AP matrix device driver
>> + */
>> +static struct ap_device_id ap_queue_ids[] = {
>> + { .dev_type = AP_DEVICE_TYPE_CEX4,
>> + .match_flags = AP_DEVICE_ID_MATCH_QUEUE_TYPE },
>> + { .dev_type = AP_DEVICE_TYPE_CEX5,
>> + .match_flags = AP_DEVICE_ID_MATCH_QUEUE_TYPE },
>> + { .dev_type = AP_DEVICE_TYPE_CEX6,
>> + .match_flags = AP_DEVICE_ID_MATCH_QUEUE_TYPE },
>> + { /* end of sibling */ },
>> +};
>> +
>> +MODULE_DEVICE_TABLE(vfio_ap, ap_queue_ids);
>> +
>> +static int vfio_ap_queue_dev_probe(struct ap_device *apdev)
>> +{
>> + return 0;
>> +}
>> +
>> +static void vfio_ap_matrix_dev_release(struct device *dev)
>> +{
>> + struct ap_matrix *ap_matrix = dev_get_drvdata(dev);
>> +
>> + kfree(ap_matrix);
>> +}
>> +
>> +static int vfio_ap_matrix_dev_create(void)
>> +{
>> + int ret;
>> +
>> + vfio_ap_root_device = root_device_register(VFIO_AP_ROOT_NAME);
>> +
>> + ret = IS_ERR(vfio_ap_root_device);
>> + if (ret) {
> Minor nit: I'd contract that to
>
> if (IS_ERR(vfio_ap_root_device)) {
>
> (you're writing ret in any case)
Okay, will do.
>
>> + ret = PTR_ERR(vfio_ap_root_device);
>> + goto done;
>> + }
>> +
>> + ap_matrix = kzalloc(sizeof(*ap_matrix), GFP_KERNEL);
>> + if (!ap_matrix) {
>> + ret = -ENOMEM;
>> + goto matrix_alloc_err;
>> + }
>> +
>> + ap_matrix->device.type = &vfio_ap_dev_type;
>> + dev_set_name(&ap_matrix->device, "%s", VFIO_AP_DEV_NAME);
>> + ap_matrix->device.parent = vfio_ap_root_device;
>> + ap_matrix->device.release = vfio_ap_matrix_dev_release;
>> + ap_matrix->device.driver = &vfio_ap_drv.driver;
>> +
>> + ret = device_register(&ap_matrix->device);
>> + if (ret)
>> + goto matrix_reg_err;
>> +
>> + goto done;
>> +
>> +matrix_reg_err:
>> + put_device(&ap_matrix->device);
>> + kfree(ap_matrix);
> The kfree() is wrong: If you called device_register for the embedded
> struct device, this needs to be handled via the ->release callback
> exclusively (IOW, the put_device() is enough and the kfree needs to go).
Ah yes, I see that. I will fix it.
>
>> +
>> +matrix_alloc_err:
>> + root_device_unregister(vfio_ap_root_device);
>> +
>> +done:
>> + return ret;
>> +}


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