thr3ads.net - Linux Virtualization - [PATCH v9 2/7] virtio-pmem: Add virtio pmem driver [May 2019]

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David Hildenbrand

2019-May-15 20:46 UTC

[PATCH v9 2/7] virtio-pmem: Add virtio pmem driver

> +	vpmem->vdev = vdev;
> +	vdev->priv = vpmem;
> +	err = init_vq(vpmem);
> +	if (err) {
> +		dev_err(&vdev->dev, "failed to initialize virtio pmem
vq's\n");
> +		goto out_err;
> +	}
> +
> +	virtio_cread(vpmem->vdev, struct virtio_pmem_config,
> +			start, &vpmem->start);
> +	virtio_cread(vpmem->vdev, struct virtio_pmem_config,
> +			size, &vpmem->size);
> +
> +	res.start = vpmem->start;
> +	res.end   = vpmem->start + vpmem->size-1;
nit: " - 1;"
> +	vpmem->nd_desc.provider_name = "virtio-pmem";
> +	vpmem->nd_desc.module = THIS_MODULE;
> +
> +	vpmem->nvdimm_bus = nvdimm_bus_register(&vdev->dev,
> +						&vpmem->nd_desc);
> +	if (!vpmem->nvdimm_bus) {
> +		dev_err(&vdev->dev, "failed to register device with
nvdimm_bus\n");
> +		err = -ENXIO;
> +		goto out_vq;
> +	}
> +
> +	dev_set_drvdata(&vdev->dev, vpmem->nvdimm_bus);
> +
> +	ndr_desc.res = &res;
> +	ndr_desc.numa_node = nid;
> +	ndr_desc.flush = async_pmem_flush;
> +	set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
> +	set_bit(ND_REGION_ASYNC, &ndr_desc.flags);
> +	nd_region = nvdimm_pmem_region_create(vpmem->nvdimm_bus,
&ndr_desc);
> +	if (!nd_region) {
> +		dev_err(&vdev->dev, "failed to create nvdimm
region\n");
> +		err = -ENXIO;
> +		goto out_nd;
> +	}
> +	nd_region->provider_data =
dev_to_virtio(nd_region->dev.parent->parent);
> +	return 0;
> +out_nd:
> +	nvdimm_bus_unregister(vpmem->nvdimm_bus);
> +out_vq:
> +	vdev->config->del_vqs(vdev);
> +out_err:
> +	return err;
> +}
> +
> +static void virtio_pmem_remove(struct virtio_device *vdev)
> +{
> +	struct nvdimm_bus *nvdimm_bus = dev_get_drvdata(&vdev->dev);
> +
> +	nvdimm_bus_unregister(nvdimm_bus);
> +	vdev->config->del_vqs(vdev);
> +	vdev->config->reset(vdev);
> +}
> +
> +static struct virtio_driver virtio_pmem_driver = {
> +	.driver.name		= KBUILD_MODNAME,
> +	.driver.owner		= THIS_MODULE,
> +	.id_table		= id_table,
> +	.probe			= virtio_pmem_probe,
> +	.remove			= virtio_pmem_remove,
> +};
> +
> +module_virtio_driver(virtio_pmem_driver);
> +MODULE_DEVICE_TABLE(virtio, id_table);
> +MODULE_DESCRIPTION("Virtio pmem driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/nvdimm/virtio_pmem.h b/drivers/nvdimm/virtio_pmem.h
> new file mode 100644
> index 000000000000..ab1da877575d
> --- /dev/null
> +++ b/drivers/nvdimm/virtio_pmem.h
> @@ -0,0 +1,60 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * virtio_pmem.h: virtio pmem Driver
> + *
> + * Discovers persistent memory range information
> + * from host and provides a virtio based flushing
> + * interface.
> + **/
> +
> +#ifndef _LINUX_VIRTIO_PMEM_H
> +#define _LINUX_VIRTIO_PMEM_H
> +
> +#include <linux/virtio_ids.h>
> +#include <linux/module.h>
> +#include <linux/virtio_config.h>
> +#include <uapi/linux/virtio_pmem.h>
> +#include <linux/libnvdimm.h>
> +#include <linux/spinlock.h>
> +
> +struct virtio_pmem_request {
> +	/* Host return status corresponding to flush request */
> +	int ret;
> +
> +	/* command name*/
> +	char name[16];
So ... why are we sending string commands and expect native-endianess
integers and don't define a proper request/response structure + request
types in include/uapi/linux/virtio_pmem.h like

struct virtio_pmem_resp {
	__virtio32 ret;
}

#define VIRTIO_PMEM_REQ_TYPE_FLUSH	1
struct virtio_pmem_req {
	__virtio16 type;
}

... and this way we also define a proper endianess format for exchange
and keep it extensible

@MST, what's your take on this?


-- 

Thanks,

David / dhildenb

David Hildenbrand

2019-May-15 20:52 UTC

head link

[PATCH v9 2/7] virtio-pmem: Add virtio pmem driver

On 15.05.19 22:46, David Hildenbrand wrote:>> +	vpmem->vdev = vdev;
>> +	vdev->priv = vpmem;
>> +	err = init_vq(vpmem);
>> +	if (err) {
>> +		dev_err(&vdev->dev, "failed to initialize virtio pmem
vq's\n");
>> +		goto out_err;
>> +	}
>> +
>> +	virtio_cread(vpmem->vdev, struct virtio_pmem_config,
>> +			start, &vpmem->start);
>> +	virtio_cread(vpmem->vdev, struct virtio_pmem_config,
>> +			size, &vpmem->size);
>> +
>> +	res.start = vpmem->start;
>> +	res.end   = vpmem->start + vpmem->size-1;
> 
> nit: " - 1;"
> 
>> +	vpmem->nd_desc.provider_name = "virtio-pmem";
>> +	vpmem->nd_desc.module = THIS_MODULE;
>> +
>> +	vpmem->nvdimm_bus = nvdimm_bus_register(&vdev->dev,
>> +						&vpmem->nd_desc);
>> +	if (!vpmem->nvdimm_bus) {
>> +		dev_err(&vdev->dev, "failed to register device with
nvdimm_bus\n");
>> +		err = -ENXIO;
>> +		goto out_vq;
>> +	}
>> +
>> +	dev_set_drvdata(&vdev->dev, vpmem->nvdimm_bus);
>> +
>> +	ndr_desc.res = &res;
>> +	ndr_desc.numa_node = nid;
>> +	ndr_desc.flush = async_pmem_flush;
>> +	set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
>> +	set_bit(ND_REGION_ASYNC, &ndr_desc.flags);
>> +	nd_region = nvdimm_pmem_region_create(vpmem->nvdimm_bus,
&ndr_desc);
>> +	if (!nd_region) {
>> +		dev_err(&vdev->dev, "failed to create nvdimm
region\n");
>> +		err = -ENXIO;
>> +		goto out_nd;
>> +	}
>> +	nd_region->provider_data =
dev_to_virtio(nd_region->dev.parent->parent);
>> +	return 0;
>> +out_nd:
>> +	nvdimm_bus_unregister(vpmem->nvdimm_bus);
>> +out_vq:
>> +	vdev->config->del_vqs(vdev);
>> +out_err:
>> +	return err;
>> +}
>> +
>> +static void virtio_pmem_remove(struct virtio_device *vdev)
>> +{
>> +	struct nvdimm_bus *nvdimm_bus = dev_get_drvdata(&vdev->dev);
>> +
>> +	nvdimm_bus_unregister(nvdimm_bus);
>> +	vdev->config->del_vqs(vdev);
>> +	vdev->config->reset(vdev);
>> +}
>> +
>> +static struct virtio_driver virtio_pmem_driver = {
>> +	.driver.name		= KBUILD_MODNAME,
>> +	.driver.owner		= THIS_MODULE,
>> +	.id_table		= id_table,
>> +	.probe			= virtio_pmem_probe,
>> +	.remove			= virtio_pmem_remove,
>> +};
>> +
>> +module_virtio_driver(virtio_pmem_driver);
>> +MODULE_DEVICE_TABLE(virtio, id_table);
>> +MODULE_DESCRIPTION("Virtio pmem driver");
>> +MODULE_LICENSE("GPL");
>> diff --git a/drivers/nvdimm/virtio_pmem.h
b/drivers/nvdimm/virtio_pmem.h
>> new file mode 100644
>> index 000000000000..ab1da877575d
>> --- /dev/null
>> +++ b/drivers/nvdimm/virtio_pmem.h
>> @@ -0,0 +1,60 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * virtio_pmem.h: virtio pmem Driver
>> + *
>> + * Discovers persistent memory range information
>> + * from host and provides a virtio based flushing
>> + * interface.
>> + **/
>> +
>> +#ifndef _LINUX_VIRTIO_PMEM_H
>> +#define _LINUX_VIRTIO_PMEM_H
>> +
>> +#include <linux/virtio_ids.h>
>> +#include <linux/module.h>
>> +#include <linux/virtio_config.h>
>> +#include <uapi/linux/virtio_pmem.h>
>> +#include <linux/libnvdimm.h>
>> +#include <linux/spinlock.h>
>> +
>> +struct virtio_pmem_request {
>> +	/* Host return status corresponding to flush request */
>> +	int ret;
>> +
>> +	/* command name*/
>> +	char name[16];
> 
> So ... why are we sending string commands and expect native-endianess
> integers and don't define a proper request/response structure + request
> types in include/uapi/linux/virtio_pmem.h like
> 
> struct virtio_pmem_resp {
> 	__virtio32 ret;
> }
FWIW, I wonder if we should even properly translate return values and
define types like

VIRTIO_PMEM_RESP_TYPE_OK	0
VIRTIO_PMEM_RESP_TYPE_EIO	1

..
> 
> #define VIRTIO_PMEM_REQ_TYPE_FLUSH	1
> struct virtio_pmem_req {
> 	__virtio16 type;
> }
> 
> ... and this way we also define a proper endianess format for exchange
> and keep it extensible
> 
> @MST, what's your take on this?
> 
> 

-- 

Thanks,

David / dhildenb

Pankaj Gupta

2019-May-16 07:49 UTC

head link

[PATCH v9 2/7] virtio-pmem: Add virtio pmem driver

> 
> > +	vpmem->vdev = vdev;
> > +	vdev->priv = vpmem;
> > +	err = init_vq(vpmem);
> > +	if (err) {
> > +		dev_err(&vdev->dev, "failed to initialize virtio pmem
vq's\n");
> > +		goto out_err;
> > +	}
> > +
> > +	virtio_cread(vpmem->vdev, struct virtio_pmem_config,
> > +			start, &vpmem->start);
> > +	virtio_cread(vpmem->vdev, struct virtio_pmem_config,
> > +			size, &vpmem->size);
> > +
> > +	res.start = vpmem->start;
> > +	res.end   = vpmem->start + vpmem->size-1;
> 
> nit: " - 1;"
Sure.
> 
> > +	vpmem->nd_desc.provider_name = "virtio-pmem";
> > +	vpmem->nd_desc.module = THIS_MODULE;
> > +
> > +	vpmem->nvdimm_bus = nvdimm_bus_register(&vdev->dev,
> > +						&vpmem->nd_desc);
> > +	if (!vpmem->nvdimm_bus) {
> > +		dev_err(&vdev->dev, "failed to register device with
nvdimm_bus\n");
> > +		err = -ENXIO;
> > +		goto out_vq;
> > +	}
> > +
> > +	dev_set_drvdata(&vdev->dev, vpmem->nvdimm_bus);
> > +
> > +	ndr_desc.res = &res;
> > +	ndr_desc.numa_node = nid;
> > +	ndr_desc.flush = async_pmem_flush;
> > +	set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
> > +	set_bit(ND_REGION_ASYNC, &ndr_desc.flags);
> > +	nd_region = nvdimm_pmem_region_create(vpmem->nvdimm_bus,
&ndr_desc);
> > +	if (!nd_region) {
> > +		dev_err(&vdev->dev, "failed to create nvdimm
region\n");
> > +		err = -ENXIO;
> > +		goto out_nd;
> > +	}
> > +	nd_region->provider_data =
dev_to_virtio(nd_region->dev.parent->parent);
> > +	return 0;
> > +out_nd:
> > +	nvdimm_bus_unregister(vpmem->nvdimm_bus);
> > +out_vq:
> > +	vdev->config->del_vqs(vdev);
> > +out_err:
> > +	return err;
> > +}
> > +
> > +static void virtio_pmem_remove(struct virtio_device *vdev)
> > +{
> > +	struct nvdimm_bus *nvdimm_bus = dev_get_drvdata(&vdev->dev);
> > +
> > +	nvdimm_bus_unregister(nvdimm_bus);
> > +	vdev->config->del_vqs(vdev);
> > +	vdev->config->reset(vdev);
> > +}
> > +
> > +static struct virtio_driver virtio_pmem_driver = {
> > +	.driver.name		= KBUILD_MODNAME,
> > +	.driver.owner		= THIS_MODULE,
> > +	.id_table		= id_table,
> > +	.probe			= virtio_pmem_probe,
> > +	.remove			= virtio_pmem_remove,
> > +};
> > +
> > +module_virtio_driver(virtio_pmem_driver);
> > +MODULE_DEVICE_TABLE(virtio, id_table);
> > +MODULE_DESCRIPTION("Virtio pmem driver");
> > +MODULE_LICENSE("GPL");
> > diff --git a/drivers/nvdimm/virtio_pmem.h
b/drivers/nvdimm/virtio_pmem.h
> > new file mode 100644
> > index 000000000000..ab1da877575d
> > --- /dev/null
> > +++ b/drivers/nvdimm/virtio_pmem.h
> > @@ -0,0 +1,60 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * virtio_pmem.h: virtio pmem Driver
> > + *
> > + * Discovers persistent memory range information
> > + * from host and provides a virtio based flushing
> > + * interface.
> > + **/
> > +
> > +#ifndef _LINUX_VIRTIO_PMEM_H
> > +#define _LINUX_VIRTIO_PMEM_H
> > +
> > +#include <linux/virtio_ids.h>
> > +#include <linux/module.h>
> > +#include <linux/virtio_config.h>
> > +#include <uapi/linux/virtio_pmem.h>
> > +#include <linux/libnvdimm.h>
> > +#include <linux/spinlock.h>
> > +
> > +struct virtio_pmem_request {
> > +	/* Host return status corresponding to flush request */
> > +	int ret;
> > +
> > +	/* command name*/
> > +	char name[16];
> 
> So ... why are we sending string commands and expect native-endianess
> integers and don't define a proper request/response structure + request
> types in include/uapi/linux/virtio_pmem.h like
> 
> struct virtio_pmem_resp {
> 	__virtio32 ret;
> }
> 
> #define VIRTIO_PMEM_REQ_TYPE_FLUSH	1
> struct virtio_pmem_req {
> 	__virtio16 type;
> }
> 
> ... and this way we also define a proper endianess format for exchange
> and keep it extensible
Done the suggested change.

Thank you,
Pankaj
> 
> @MST, what's your take on this?
> 
> 
> --
> 
> Thanks,
> 
> David / dhildenb
>

Pankaj Gupta

2019-May-16 07:54 UTC

head link

[PATCH v9 2/7] virtio-pmem: Add virtio pmem driver

> >> +	vpmem->vdev = vdev;
> >> +	vdev->priv = vpmem;
> >> +	err = init_vq(vpmem);
> >> +	if (err) {
> >> +		dev_err(&vdev->dev, "failed to initialize virtio
pmem vq's\n");
> >> +		goto out_err;
> >> +	}
> >> +
> >> +	virtio_cread(vpmem->vdev, struct virtio_pmem_config,
> >> +			start, &vpmem->start);
> >> +	virtio_cread(vpmem->vdev, struct virtio_pmem_config,
> >> +			size, &vpmem->size);
> >> +
> >> +	res.start = vpmem->start;
> >> +	res.end   = vpmem->start + vpmem->size-1;
> > 
> > nit: " - 1;"
> > 
> >> +	vpmem->nd_desc.provider_name = "virtio-pmem";
> >> +	vpmem->nd_desc.module = THIS_MODULE;
> >> +
> >> +	vpmem->nvdimm_bus = nvdimm_bus_register(&vdev->dev,
> >> +						&vpmem->nd_desc);
> >> +	if (!vpmem->nvdimm_bus) {
> >> +		dev_err(&vdev->dev, "failed to register device with
nvdimm_bus\n");
> >> +		err = -ENXIO;
> >> +		goto out_vq;
> >> +	}
> >> +
> >> +	dev_set_drvdata(&vdev->dev, vpmem->nvdimm_bus);
> >> +
> >> +	ndr_desc.res = &res;
> >> +	ndr_desc.numa_node = nid;
> >> +	ndr_desc.flush = async_pmem_flush;
> >> +	set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
> >> +	set_bit(ND_REGION_ASYNC, &ndr_desc.flags);
> >> +	nd_region = nvdimm_pmem_region_create(vpmem->nvdimm_bus,
&ndr_desc);
> >> +	if (!nd_region) {
> >> +		dev_err(&vdev->dev, "failed to create nvdimm
region\n");
> >> +		err = -ENXIO;
> >> +		goto out_nd;
> >> +	}
> >> +	nd_region->provider_data =
dev_to_virtio(nd_region->dev.parent->parent);
> >> +	return 0;
> >> +out_nd:
> >> +	nvdimm_bus_unregister(vpmem->nvdimm_bus);
> >> +out_vq:
> >> +	vdev->config->del_vqs(vdev);
> >> +out_err:
> >> +	return err;
> >> +}
> >> +
> >> +static void virtio_pmem_remove(struct virtio_device *vdev)
> >> +{
> >> +	struct nvdimm_bus *nvdimm_bus =
dev_get_drvdata(&vdev->dev);
> >> +
> >> +	nvdimm_bus_unregister(nvdimm_bus);
> >> +	vdev->config->del_vqs(vdev);
> >> +	vdev->config->reset(vdev);
> >> +}
> >> +
> >> +static struct virtio_driver virtio_pmem_driver = {
> >> +	.driver.name		= KBUILD_MODNAME,
> >> +	.driver.owner		= THIS_MODULE,
> >> +	.id_table		= id_table,
> >> +	.probe			= virtio_pmem_probe,
> >> +	.remove			= virtio_pmem_remove,
> >> +};
> >> +
> >> +module_virtio_driver(virtio_pmem_driver);
> >> +MODULE_DEVICE_TABLE(virtio, id_table);
> >> +MODULE_DESCRIPTION("Virtio pmem driver");
> >> +MODULE_LICENSE("GPL");
> >> diff --git a/drivers/nvdimm/virtio_pmem.h
b/drivers/nvdimm/virtio_pmem.h
> >> new file mode 100644
> >> index 000000000000..ab1da877575d
> >> --- /dev/null
> >> +++ b/drivers/nvdimm/virtio_pmem.h
> >> @@ -0,0 +1,60 @@
> >> +/* SPDX-License-Identifier: GPL-2.0 */
> >> +/*
> >> + * virtio_pmem.h: virtio pmem Driver
> >> + *
> >> + * Discovers persistent memory range information
> >> + * from host and provides a virtio based flushing
> >> + * interface.
> >> + **/
> >> +
> >> +#ifndef _LINUX_VIRTIO_PMEM_H
> >> +#define _LINUX_VIRTIO_PMEM_H
> >> +
> >> +#include <linux/virtio_ids.h>
> >> +#include <linux/module.h>
> >> +#include <linux/virtio_config.h>
> >> +#include <uapi/linux/virtio_pmem.h>
> >> +#include <linux/libnvdimm.h>
> >> +#include <linux/spinlock.h>
> >> +
> >> +struct virtio_pmem_request {
> >> +	/* Host return status corresponding to flush request */
> >> +	int ret;
> >> +
> >> +	/* command name*/
> >> +	char name[16];
> > 
> > So ... why are we sending string commands and expect native-endianess
> > integers and don't define a proper request/response structure +
request
> > types in include/uapi/linux/virtio_pmem.h like
> > 
> > struct virtio_pmem_resp {
> > 	__virtio32 ret;
> > }
> 
> FWIW, I wonder if we should even properly translate return values and
> define types like
> 
> VIRTIO_PMEM_RESP_TYPE_OK	0
> VIRTIO_PMEM_RESP_TYPE_EIO	1
Don't think these are required as only failure and success
return types easy to understand.

Thanks,
Pankaj> 
> ..
> 
> > 
> > #define VIRTIO_PMEM_REQ_TYPE_FLUSH	1
> > struct virtio_pmem_req {
> > 	__virtio16 type;
> > }
> > 
> > ... and this way we also define a proper endianess format for exchange
> > and keep it extensible
> > 
> > @MST, what's your take on this?
> > 
> > 
> 
> 
> --
> 
> Thanks,
> 
> David / dhildenb
>

Michael S. Tsirkin

2019-May-16 13:59 UTC

head link

[PATCH v9 2/7] virtio-pmem: Add virtio pmem driver

On Wed, May 15, 2019 at 10:46:00PM +0200, David Hildenbrand
wrote:> > +	vpmem->vdev = vdev;
> > +	vdev->priv = vpmem;
> > +	err = init_vq(vpmem);
> > +	if (err) {
> > +		dev_err(&vdev->dev, "failed to initialize virtio pmem
vq's\n");
> > +		goto out_err;
> > +	}
> > +
> > +	virtio_cread(vpmem->vdev, struct virtio_pmem_config,
> > +			start, &vpmem->start);
> > +	virtio_cread(vpmem->vdev, struct virtio_pmem_config,
> > +			size, &vpmem->size);
> > +
> > +	res.start = vpmem->start;
> > +	res.end   = vpmem->start + vpmem->size-1;
> 
> nit: " - 1;"
> 
> > +	vpmem->nd_desc.provider_name = "virtio-pmem";
> > +	vpmem->nd_desc.module = THIS_MODULE;
> > +
> > +	vpmem->nvdimm_bus = nvdimm_bus_register(&vdev->dev,
> > +						&vpmem->nd_desc);
> > +	if (!vpmem->nvdimm_bus) {
> > +		dev_err(&vdev->dev, "failed to register device with
nvdimm_bus\n");
> > +		err = -ENXIO;
> > +		goto out_vq;
> > +	}
> > +
> > +	dev_set_drvdata(&vdev->dev, vpmem->nvdimm_bus);
> > +
> > +	ndr_desc.res = &res;
> > +	ndr_desc.numa_node = nid;
> > +	ndr_desc.flush = async_pmem_flush;
> > +	set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
> > +	set_bit(ND_REGION_ASYNC, &ndr_desc.flags);
> > +	nd_region = nvdimm_pmem_region_create(vpmem->nvdimm_bus,
&ndr_desc);
> > +	if (!nd_region) {
> > +		dev_err(&vdev->dev, "failed to create nvdimm
region\n");
> > +		err = -ENXIO;
> > +		goto out_nd;
> > +	}
> > +	nd_region->provider_data =
dev_to_virtio(nd_region->dev.parent->parent);
> > +	return 0;
> > +out_nd:
> > +	nvdimm_bus_unregister(vpmem->nvdimm_bus);
> > +out_vq:
> > +	vdev->config->del_vqs(vdev);
> > +out_err:
> > +	return err;
> > +}
> > +
> > +static void virtio_pmem_remove(struct virtio_device *vdev)
> > +{
> > +	struct nvdimm_bus *nvdimm_bus = dev_get_drvdata(&vdev->dev);
> > +
> > +	nvdimm_bus_unregister(nvdimm_bus);
> > +	vdev->config->del_vqs(vdev);
> > +	vdev->config->reset(vdev);
> > +}
> > +
> > +static struct virtio_driver virtio_pmem_driver = {
> > +	.driver.name		= KBUILD_MODNAME,
> > +	.driver.owner		= THIS_MODULE,
> > +	.id_table		= id_table,
> > +	.probe			= virtio_pmem_probe,
> > +	.remove			= virtio_pmem_remove,
> > +};
> > +
> > +module_virtio_driver(virtio_pmem_driver);
> > +MODULE_DEVICE_TABLE(virtio, id_table);
> > +MODULE_DESCRIPTION("Virtio pmem driver");
> > +MODULE_LICENSE("GPL");
> > diff --git a/drivers/nvdimm/virtio_pmem.h
b/drivers/nvdimm/virtio_pmem.h
> > new file mode 100644
> > index 000000000000..ab1da877575d
> > --- /dev/null
> > +++ b/drivers/nvdimm/virtio_pmem.h
> > @@ -0,0 +1,60 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * virtio_pmem.h: virtio pmem Driver
> > + *
> > + * Discovers persistent memory range information
> > + * from host and provides a virtio based flushing
> > + * interface.
> > + **/
> > +
> > +#ifndef _LINUX_VIRTIO_PMEM_H
> > +#define _LINUX_VIRTIO_PMEM_H
> > +
> > +#include <linux/virtio_ids.h>
> > +#include <linux/module.h>
> > +#include <linux/virtio_config.h>
> > +#include <uapi/linux/virtio_pmem.h>
> > +#include <linux/libnvdimm.h>
> > +#include <linux/spinlock.h>
> > +
> > +struct virtio_pmem_request {
> > +	/* Host return status corresponding to flush request */
> > +	int ret;
> > +
> > +	/* command name*/
> > +	char name[16];
> 
> So ... why are we sending string commands and expect native-endianess
> integers and don't define a proper request/response structure + request
> types in include/uapi/linux/virtio_pmem.h like
passing names could be ok.
I missed the fact we return a native endian int.
Pls fix that.

> 
> struct virtio_pmem_resp {
> 	__virtio32 ret;
> }
> 
> #define VIRTIO_PMEM_REQ_TYPE_FLUSH	1
> struct virtio_pmem_req {
> 	__virtio16 type;
> }
> 
> ... and this way we also define a proper endianess format for exchange
> and keep it extensible
> 
> @MST, what's your take on this?
Extensions can always use feature bits so I don't think
it's a problem.
> 
> -- 
> 
> Thanks,
> 
> David / dhildenb

Pankaj Gupta

2019-May-17 05:31 UTC

head link

[Qemu-devel] [PATCH v9 2/7] virtio-pmem: Add virtio pmem driver

> 
> On Wed, May 15, 2019 at 10:46:00PM +0200, David Hildenbrand wrote:
> > > +	vpmem->vdev = vdev;
> > > +	vdev->priv = vpmem;
> > > +	err = init_vq(vpmem);
> > > +	if (err) {
> > > +		dev_err(&vdev->dev, "failed to initialize virtio
pmem vq's\n");
> > > +		goto out_err;
> > > +	}
> > > +
> > > +	virtio_cread(vpmem->vdev, struct virtio_pmem_config,
> > > +			start, &vpmem->start);
> > > +	virtio_cread(vpmem->vdev, struct virtio_pmem_config,
> > > +			size, &vpmem->size);
> > > +
> > > +	res.start = vpmem->start;
> > > +	res.end   = vpmem->start + vpmem->size-1;
> > 
> > nit: " - 1;"
> > 
> > > +	vpmem->nd_desc.provider_name = "virtio-pmem";
> > > +	vpmem->nd_desc.module = THIS_MODULE;
> > > +
> > > +	vpmem->nvdimm_bus = nvdimm_bus_register(&vdev->dev,
> > > +						&vpmem->nd_desc);
> > > +	if (!vpmem->nvdimm_bus) {
> > > +		dev_err(&vdev->dev, "failed to register device
with nvdimm_bus\n");
> > > +		err = -ENXIO;
> > > +		goto out_vq;
> > > +	}
> > > +
> > > +	dev_set_drvdata(&vdev->dev, vpmem->nvdimm_bus);
> > > +
> > > +	ndr_desc.res = &res;
> > > +	ndr_desc.numa_node = nid;
> > > +	ndr_desc.flush = async_pmem_flush;
> > > +	set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
> > > +	set_bit(ND_REGION_ASYNC, &ndr_desc.flags);
> > > +	nd_region = nvdimm_pmem_region_create(vpmem->nvdimm_bus,
&ndr_desc);
> > > +	if (!nd_region) {
> > > +		dev_err(&vdev->dev, "failed to create nvdimm
region\n");
> > > +		err = -ENXIO;
> > > +		goto out_nd;
> > > +	}
> > > +	nd_region->provider_data > > >
dev_to_virtio(nd_region->dev.parent->parent);
> > > +	return 0;
> > > +out_nd:
> > > +	nvdimm_bus_unregister(vpmem->nvdimm_bus);
> > > +out_vq:
> > > +	vdev->config->del_vqs(vdev);
> > > +out_err:
> > > +	return err;
> > > +}
> > > +
> > > +static void virtio_pmem_remove(struct virtio_device *vdev)
> > > +{
> > > +	struct nvdimm_bus *nvdimm_bus =
dev_get_drvdata(&vdev->dev);
> > > +
> > > +	nvdimm_bus_unregister(nvdimm_bus);
> > > +	vdev->config->del_vqs(vdev);
> > > +	vdev->config->reset(vdev);
> > > +}
> > > +
> > > +static struct virtio_driver virtio_pmem_driver = {
> > > +	.driver.name		= KBUILD_MODNAME,
> > > +	.driver.owner		= THIS_MODULE,
> > > +	.id_table		= id_table,
> > > +	.probe			= virtio_pmem_probe,
> > > +	.remove			= virtio_pmem_remove,
> > > +};
> > > +
> > > +module_virtio_driver(virtio_pmem_driver);
> > > +MODULE_DEVICE_TABLE(virtio, id_table);
> > > +MODULE_DESCRIPTION("Virtio pmem driver");
> > > +MODULE_LICENSE("GPL");
> > > diff --git a/drivers/nvdimm/virtio_pmem.h
b/drivers/nvdimm/virtio_pmem.h
> > > new file mode 100644
> > > index 000000000000..ab1da877575d
> > > --- /dev/null
> > > +++ b/drivers/nvdimm/virtio_pmem.h
> > > @@ -0,0 +1,60 @@
> > > +/* SPDX-License-Identifier: GPL-2.0 */
> > > +/*
> > > + * virtio_pmem.h: virtio pmem Driver
> > > + *
> > > + * Discovers persistent memory range information
> > > + * from host and provides a virtio based flushing
> > > + * interface.
> > > + **/
> > > +
> > > +#ifndef _LINUX_VIRTIO_PMEM_H
> > > +#define _LINUX_VIRTIO_PMEM_H
> > > +
> > > +#include <linux/virtio_ids.h>
> > > +#include <linux/module.h>
> > > +#include <linux/virtio_config.h>
> > > +#include <uapi/linux/virtio_pmem.h>
> > > +#include <linux/libnvdimm.h>
> > > +#include <linux/spinlock.h>
> > > +
> > > +struct virtio_pmem_request {
> > > +	/* Host return status corresponding to flush request */
> > > +	int ret;
> > > +
> > > +	/* command name*/
> > > +	char name[16];
> > 
> > So ... why are we sending string commands and expect native-endianess
> > integers and don't define a proper request/response structure +
request
> > types in include/uapi/linux/virtio_pmem.h like
> 
> passing names could be ok.
> I missed the fact we return a native endian int.
> Pls fix that.
Sure. will fix this.
> 
> 
> > 
> > struct virtio_pmem_resp {
> > 	__virtio32 ret;
> > }
> > 
> > #define VIRTIO_PMEM_REQ_TYPE_FLUSH	1
> > struct virtio_pmem_req {
> > 	__virtio16 type;
> > }
> > 
> > ... and this way we also define a proper endianess format for exchange
> > and keep it extensible
> > 
> > @MST, what's your take on this?
> 
> Extensions can always use feature bits so I don't think
> it's a problem.
That was exactly my thought when I implemented this. Though I am
fine with separate structures for request/response and I made the
change. 

Thank you for all the comments.

Best regards,
Pankaj > > 
> > --
> > 
> > Thanks,
> > 
> > David / dhildenb
> 
>

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