[v4,6/6] vfio-ccw: add handling for async channel instructions
diff mbox series

Message ID 20190301093902.27799-7-cohuck@redhat.com
State New
Headers show
Series
  • vfio-ccw: support hsch/csch (kernel part)
Related show

Commit Message

Cornelia Huck March 1, 2019, 9:39 a.m. UTC
Add a region to the vfio-ccw device that can be used to submit
asynchronous I/O instructions. ssch continues to be handled by the
existing I/O region; the new region handles hsch and csch.

Interrupt status continues to be reported through the same channels
as for ssch.

Signed-off-by: Cornelia Huck <cohuck@redhat.com>
---
 drivers/s390/cio/Makefile           |   3 +-
 drivers/s390/cio/vfio_ccw_async.c   |  88 ++++++++++++++++++++
 drivers/s390/cio/vfio_ccw_drv.c     |  46 ++++++++---
 drivers/s390/cio/vfio_ccw_fsm.c     | 119 +++++++++++++++++++++++++++-
 drivers/s390/cio/vfio_ccw_ops.c     |  13 ++-
 drivers/s390/cio/vfio_ccw_private.h |   5 ++
 include/uapi/linux/vfio.h           |   2 +
 include/uapi/linux/vfio_ccw.h       |  12 +++
 8 files changed, 270 insertions(+), 18 deletions(-)
 create mode 100644 drivers/s390/cio/vfio_ccw_async.c

Comments

Eric Farman April 15, 2019, 2:56 p.m. UTC | #1
On 3/1/19 4:39 AM, Cornelia Huck wrote:
> Add a region to the vfio-ccw device that can be used to submit
> asynchronous I/O instructions. ssch continues to be handled by the
> existing I/O region; the new region handles hsch and csch.
> 
> Interrupt status continues to be reported through the same channels
> as for ssch.
> 
> Signed-off-by: Cornelia Huck <cohuck@redhat.com>

This all looks pretty sensible to me.  Sorry my interminable delays!

Acked-by: Eric Farman <farman@linux.ibm.com>

> ---
>   drivers/s390/cio/Makefile           |   3 +-
>   drivers/s390/cio/vfio_ccw_async.c   |  88 ++++++++++++++++++++
>   drivers/s390/cio/vfio_ccw_drv.c     |  46 ++++++++---
>   drivers/s390/cio/vfio_ccw_fsm.c     | 119 +++++++++++++++++++++++++++-
>   drivers/s390/cio/vfio_ccw_ops.c     |  13 ++-
>   drivers/s390/cio/vfio_ccw_private.h |   5 ++
>   include/uapi/linux/vfio.h           |   2 +
>   include/uapi/linux/vfio_ccw.h       |  12 +++
>   8 files changed, 270 insertions(+), 18 deletions(-)
>   create mode 100644 drivers/s390/cio/vfio_ccw_async.c
> 
> diff --git a/drivers/s390/cio/Makefile b/drivers/s390/cio/Makefile
> index f230516abb96..f6a8db04177c 100644
> --- a/drivers/s390/cio/Makefile
> +++ b/drivers/s390/cio/Makefile
> @@ -20,5 +20,6 @@ obj-$(CONFIG_CCWGROUP) += ccwgroup.o
>   qdio-objs := qdio_main.o qdio_thinint.o qdio_debug.o qdio_setup.o
>   obj-$(CONFIG_QDIO) += qdio.o
>   
> -vfio_ccw-objs += vfio_ccw_drv.o vfio_ccw_cp.o vfio_ccw_ops.o vfio_ccw_fsm.o
> +vfio_ccw-objs += vfio_ccw_drv.o vfio_ccw_cp.o vfio_ccw_ops.o vfio_ccw_fsm.o \
> +	vfio_ccw_async.o
>   obj-$(CONFIG_VFIO_CCW) += vfio_ccw.o
> diff --git a/drivers/s390/cio/vfio_ccw_async.c b/drivers/s390/cio/vfio_ccw_async.c
> new file mode 100644
> index 000000000000..8c1d2357ef5b
> --- /dev/null
> +++ b/drivers/s390/cio/vfio_ccw_async.c
> @@ -0,0 +1,88 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Async I/O region for vfio_ccw
> + *
> + * Copyright Red Hat, Inc. 2019
> + *
> + * Author(s): Cornelia Huck <cohuck@redhat.com>
> + */
> +
> +#include <linux/vfio.h>
> +#include <linux/mdev.h>
> +
> +#include "vfio_ccw_private.h"
> +
> +static ssize_t vfio_ccw_async_region_read(struct vfio_ccw_private *private,
> +					  char __user *buf, size_t count,
> +					  loff_t *ppos)
> +{
> +	unsigned int i = VFIO_CCW_OFFSET_TO_INDEX(*ppos) - VFIO_CCW_NUM_REGIONS;
> +	loff_t pos = *ppos & VFIO_CCW_OFFSET_MASK;
> +	struct ccw_cmd_region *region;
> +	int ret;
> +
> +	if (pos + count > sizeof(*region))
> +		return -EINVAL;
> +
> +	mutex_lock(&private->io_mutex);
> +	region = private->region[i].data;
> +	if (copy_to_user(buf, (void *)region + pos, count))
> +		ret = -EFAULT;
> +	else
> +		ret = count;
> +	mutex_unlock(&private->io_mutex);
> +	return ret;
> +}
> +
> +static ssize_t vfio_ccw_async_region_write(struct vfio_ccw_private *private,
> +					   const char __user *buf, size_t count,
> +					   loff_t *ppos)
> +{
> +	unsigned int i = VFIO_CCW_OFFSET_TO_INDEX(*ppos) - VFIO_CCW_NUM_REGIONS;
> +	loff_t pos = *ppos & VFIO_CCW_OFFSET_MASK;
> +	struct ccw_cmd_region *region;
> +	int ret;
> +
> +	if (pos + count > sizeof(*region))
> +		return -EINVAL;
> +
> +	if (!mutex_trylock(&private->io_mutex))
> +		return -EAGAIN;
> +
> +	region = private->region[i].data;
> +	if (copy_from_user((void *)region + pos, buf, count)) {
> +		ret = -EFAULT;
> +		goto out_unlock;
> +	}
> +
> +	vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_ASYNC_REQ);
> +
> +	ret = region->ret_code ? region->ret_code : count;
> +
> +out_unlock:
> +	mutex_unlock(&private->io_mutex);
> +	return ret;
> +}
> +
> +static void vfio_ccw_async_region_release(struct vfio_ccw_private *private,
> +					  struct vfio_ccw_region *region)
> +{
> +
> +}
> +
> +const struct vfio_ccw_regops vfio_ccw_async_region_ops = {
> +	.read = vfio_ccw_async_region_read,
> +	.write = vfio_ccw_async_region_write,
> +	.release = vfio_ccw_async_region_release,
> +};
> +
> +int vfio_ccw_register_async_dev_regions(struct vfio_ccw_private *private)
> +{
> +	return vfio_ccw_register_dev_region(private,
> +					    VFIO_REGION_SUBTYPE_CCW_ASYNC_CMD,
> +					    &vfio_ccw_async_region_ops,
> +					    sizeof(struct ccw_cmd_region),
> +					    VFIO_REGION_INFO_FLAG_READ |
> +					    VFIO_REGION_INFO_FLAG_WRITE,
> +					    private->cmd_region);
> +}
> diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
> index 5ea0da1dd954..c39d01943a6a 100644
> --- a/drivers/s390/cio/vfio_ccw_drv.c
> +++ b/drivers/s390/cio/vfio_ccw_drv.c
> @@ -3,9 +3,11 @@
>    * VFIO based Physical Subchannel device driver
>    *
>    * Copyright IBM Corp. 2017
> + * Copyright Red Hat, Inc. 2019
>    *
>    * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
>    *            Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
> + *            Cornelia Huck <cohuck@redhat.com>
>    */
>   
>   #include <linux/module.h>
> @@ -23,6 +25,7 @@
>   
>   struct workqueue_struct *vfio_ccw_work_q;
>   static struct kmem_cache *vfio_ccw_io_region;
> +static struct kmem_cache *vfio_ccw_cmd_region;
>   
>   /*
>    * Helpers
> @@ -110,7 +113,7 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
>   {
>   	struct pmcw *pmcw = &sch->schib.pmcw;
>   	struct vfio_ccw_private *private;
> -	int ret;
> +	int ret = -ENOMEM;
>   
>   	if (pmcw->qf) {
>   		dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
> @@ -124,10 +127,13 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
>   
>   	private->io_region = kmem_cache_zalloc(vfio_ccw_io_region,
>   					       GFP_KERNEL | GFP_DMA);
> -	if (!private->io_region) {
> -		kfree(private);
> -		return -ENOMEM;
> -	}
> +	if (!private->io_region)
> +		goto out_free;
> +
> +	private->cmd_region = kmem_cache_zalloc(vfio_ccw_cmd_region,
> +						GFP_KERNEL | GFP_DMA);
> +	if (!private->cmd_region)
> +		goto out_free;
>   
>   	private->sch = sch;
>   	dev_set_drvdata(&sch->dev, private);
> @@ -155,7 +161,10 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
>   	cio_disable_subchannel(sch);
>   out_free:
>   	dev_set_drvdata(&sch->dev, NULL);
> -	kmem_cache_free(vfio_ccw_io_region, private->io_region);
> +	if (private->cmd_region)
> +		kmem_cache_free(vfio_ccw_cmd_region, private->cmd_region);
> +	if (private->io_region)
> +		kmem_cache_free(vfio_ccw_io_region, private->io_region);
>   	kfree(private);
>   	return ret;
>   }
> @@ -170,6 +179,7 @@ static int vfio_ccw_sch_remove(struct subchannel *sch)
>   
>   	dev_set_drvdata(&sch->dev, NULL);
>   
> +	kmem_cache_free(vfio_ccw_cmd_region, private->cmd_region);
>   	kmem_cache_free(vfio_ccw_io_region, private->io_region);
>   	kfree(private);
>   
> @@ -244,7 +254,7 @@ static struct css_driver vfio_ccw_sch_driver = {
>   
>   static int __init vfio_ccw_sch_init(void)
>   {
> -	int ret;
> +	int ret = -ENOMEM;
>   
>   	vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
>   	if (!vfio_ccw_work_q)
> @@ -254,20 +264,30 @@ static int __init vfio_ccw_sch_init(void)
>   					sizeof(struct ccw_io_region), 0,
>   					SLAB_ACCOUNT, 0,
>   					sizeof(struct ccw_io_region), NULL);
> -	if (!vfio_ccw_io_region) {
> -		destroy_workqueue(vfio_ccw_work_q);
> -		return -ENOMEM;
> -	}
> +	if (!vfio_ccw_io_region)
> +		goto out_err;
> +
> +	vfio_ccw_cmd_region = kmem_cache_create_usercopy("vfio_ccw_cmd_region",
> +					sizeof(struct ccw_cmd_region), 0,
> +					SLAB_ACCOUNT, 0,
> +					sizeof(struct ccw_cmd_region), NULL);
> +	if (!vfio_ccw_cmd_region)
> +		goto out_err;
>   
>   	isc_register(VFIO_CCW_ISC);
>   	ret = css_driver_register(&vfio_ccw_sch_driver);
>   	if (ret) {
>   		isc_unregister(VFIO_CCW_ISC);
> -		kmem_cache_destroy(vfio_ccw_io_region);
> -		destroy_workqueue(vfio_ccw_work_q);
> +		goto out_err;
>   	}
>   
>   	return ret;
> +
> +out_err:
> +	kmem_cache_destroy(vfio_ccw_cmd_region);
> +	kmem_cache_destroy(vfio_ccw_io_region);
> +	destroy_workqueue(vfio_ccw_work_q);
> +	return ret;
>   }
>   
>   static void __exit vfio_ccw_sch_exit(void)
> diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c
> index b4a141fbd1a8..49d9d3da0282 100644
> --- a/drivers/s390/cio/vfio_ccw_fsm.c
> +++ b/drivers/s390/cio/vfio_ccw_fsm.c
> @@ -3,8 +3,10 @@
>    * Finite state machine for vfio-ccw device handling
>    *
>    * Copyright IBM Corp. 2017
> + * Copyright Red Hat, Inc. 2019
>    *
>    * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
> + *            Cornelia Huck <cohuck@redhat.com>
>    */
>   
>   #include <linux/vfio.h>
> @@ -73,6 +75,75 @@ static int fsm_io_helper(struct vfio_ccw_private *private)
>   	return ret;
>   }
>   
> +static int fsm_do_halt(struct vfio_ccw_private *private)
> +{
> +	struct subchannel *sch;
> +	unsigned long flags;
> +	int ccode;
> +	int ret;
> +
> +	sch = private->sch;
> +
> +	spin_lock_irqsave(sch->lock, flags);
> +
> +	/* Issue "Halt Subchannel" */
> +	ccode = hsch(sch->schid);
> +
> +	switch (ccode) {
> +	case 0:
> +		/*
> +		 * Initialize device status information
> +		 */
> +		sch->schib.scsw.cmd.actl |= SCSW_ACTL_HALT_PEND;
> +		ret = 0;
> +		break;
> +	case 1:		/* Status pending */
> +	case 2:		/* Busy */
> +		ret = -EBUSY;
> +		break;
> +	case 3:		/* Device not operational */
> +		ret = -ENODEV;
> +		break;
> +	default:
> +		ret = ccode;
> +	}
> +	spin_unlock_irqrestore(sch->lock, flags);
> +	return ret;
> +}
> +
> +static int fsm_do_clear(struct vfio_ccw_private *private)
> +{
> +	struct subchannel *sch;
> +	unsigned long flags;
> +	int ccode;
> +	int ret;
> +
> +	sch = private->sch;
> +
> +	spin_lock_irqsave(sch->lock, flags);
> +
> +	/* Issue "Clear Subchannel" */
> +	ccode = csch(sch->schid);
> +
> +	switch (ccode) {
> +	case 0:
> +		/*
> +		 * Initialize device status information
> +		 */
> +		sch->schib.scsw.cmd.actl = SCSW_ACTL_CLEAR_PEND;
> +		/* TODO: check what else we might need to clear */
> +		ret = 0;
> +		break;
> +	case 3:		/* Device not operational */
> +		ret = -ENODEV;
> +		break;
> +	default:
> +		ret = ccode;
> +	}
> +	spin_unlock_irqrestore(sch->lock, flags);
> +	return ret;
> +}
> +
>   static void fsm_notoper(struct vfio_ccw_private *private,
>   			enum vfio_ccw_event event)
>   {
> @@ -113,6 +184,24 @@ static void fsm_io_retry(struct vfio_ccw_private *private,
>   	private->io_region->ret_code = -EAGAIN;
>   }
>   
> +static void fsm_async_error(struct vfio_ccw_private *private,
> +			    enum vfio_ccw_event event)
> +{
> +	struct ccw_cmd_region *cmd_region = private->cmd_region;
> +
> +	pr_err("vfio-ccw: FSM: %s request from state:%d\n",
> +	       cmd_region->command == VFIO_CCW_ASYNC_CMD_HSCH ? "halt" :
> +	       cmd_region->command == VFIO_CCW_ASYNC_CMD_CSCH ? "clear" :
> +	       "<unknown>", private->state);
> +	cmd_region->ret_code = -EIO;
> +}
> +
> +static void fsm_async_retry(struct vfio_ccw_private *private,
> +			    enum vfio_ccw_event event)
> +{
> +	private->cmd_region->ret_code = -EAGAIN;
> +}
> +
>   static void fsm_disabled_irq(struct vfio_ccw_private *private,
>   			     enum vfio_ccw_event event)
>   {
> @@ -176,11 +265,11 @@ static void fsm_io_request(struct vfio_ccw_private *private,
>   		}
>   		return;
>   	} else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) {
> -		/* XXX: Handle halt. */
> +		/* halt is handled via the async cmd region */
>   		io_region->ret_code = -EOPNOTSUPP;
>   		goto err_out;
>   	} else if (scsw->cmd.fctl & SCSW_FCTL_CLEAR_FUNC) {
> -		/* XXX: Handle clear. */
> +		/* clear is handled via the async cmd region */
>   		io_region->ret_code = -EOPNOTSUPP;
>   		goto err_out;
>   	}
> @@ -190,6 +279,27 @@ static void fsm_io_request(struct vfio_ccw_private *private,
>   			       io_region->ret_code, errstr);
>   }
>   
> +/*
> + * Deal with an async request from userspace.
> + */
> +static void fsm_async_request(struct vfio_ccw_private *private,
> +			      enum vfio_ccw_event event)
> +{
> +	struct ccw_cmd_region *cmd_region = private->cmd_region;
> +
> +	switch (cmd_region->command) {
> +	case VFIO_CCW_ASYNC_CMD_HSCH:
> +		cmd_region->ret_code = fsm_do_halt(private);
> +		break;
> +	case VFIO_CCW_ASYNC_CMD_CSCH:
> +		cmd_region->ret_code = fsm_do_clear(private);
> +		break;
> +	default:
> +		/* should not happen? */
> +		cmd_region->ret_code = -EINVAL;
> +	}
> +}
> +
>   /*
>    * Got an interrupt for a normal io (state busy).
>    */
> @@ -213,26 +323,31 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
>   	[VFIO_CCW_STATE_NOT_OPER] = {
>   		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_nop,
>   		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_error,
> +		[VFIO_CCW_EVENT_ASYNC_REQ]	= fsm_async_error,
>   		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_disabled_irq,
>   	},
>   	[VFIO_CCW_STATE_STANDBY] = {
>   		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_notoper,
>   		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_error,
> +		[VFIO_CCW_EVENT_ASYNC_REQ]	= fsm_async_error,
>   		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_irq,
>   	},
>   	[VFIO_CCW_STATE_IDLE] = {
>   		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_notoper,
>   		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_request,
> +		[VFIO_CCW_EVENT_ASYNC_REQ]	= fsm_async_request,
>   		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_irq,
>   	},
>   	[VFIO_CCW_STATE_CP_PROCESSING] = {
>   		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_notoper,
>   		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_retry,
> +		[VFIO_CCW_EVENT_ASYNC_REQ]	= fsm_async_retry,
>   		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_irq,
>   	},
>   	[VFIO_CCW_STATE_CP_PENDING] = {
>   		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_notoper,
>   		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_busy,
> +		[VFIO_CCW_EVENT_ASYNC_REQ]	= fsm_async_request,
>   		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_irq,
>   	},
>   };
> diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
> index 3fd663320bbf..ec2f796c70fe 100644
> --- a/drivers/s390/cio/vfio_ccw_ops.c
> +++ b/drivers/s390/cio/vfio_ccw_ops.c
> @@ -149,11 +149,20 @@ static int vfio_ccw_mdev_open(struct mdev_device *mdev)
>   	struct vfio_ccw_private *private =
>   		dev_get_drvdata(mdev_parent_dev(mdev));
>   	unsigned long events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
> +	int ret;
>   
>   	private->nb.notifier_call = vfio_ccw_mdev_notifier;
>   
> -	return vfio_register_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
> -				      &events, &private->nb);
> +	ret = vfio_register_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
> +				     &events, &private->nb);
> +	if (ret)
> +		return ret;
> +
> +	ret = vfio_ccw_register_async_dev_regions(private);
> +	if (ret)
> +		vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
> +					 &private->nb);
> +	return ret;
>   }
>   
>   static void vfio_ccw_mdev_release(struct mdev_device *mdev)
> diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
> index d888a2573470..f1092c3dc1b1 100644
> --- a/drivers/s390/cio/vfio_ccw_private.h
> +++ b/drivers/s390/cio/vfio_ccw_private.h
> @@ -53,6 +53,8 @@ int vfio_ccw_register_dev_region(struct vfio_ccw_private *private,
>   				 const struct vfio_ccw_regops *ops,
>   				 size_t size, u32 flags, void *data);
>   
> +int vfio_ccw_register_async_dev_regions(struct vfio_ccw_private *private);
> +
>   /**
>    * struct vfio_ccw_private
>    * @sch: pointer to the subchannel
> @@ -64,6 +66,7 @@ int vfio_ccw_register_dev_region(struct vfio_ccw_private *private,
>    * @io_region: MMIO region to input/output I/O arguments/results
>    * @io_mutex: protect against concurrent update of I/O regions
>    * @region: additional regions for other subchannel operations
> + * @cmd_region: MMIO region for asynchronous I/O commands other than START
>    * @num_regions: number of additional regions
>    * @cp: channel program for the current I/O operation
>    * @irb: irb info received from interrupt
> @@ -81,6 +84,7 @@ struct vfio_ccw_private {
>   	struct ccw_io_region	*io_region;
>   	struct mutex		io_mutex;
>   	struct vfio_ccw_region *region;
> +	struct ccw_cmd_region	*cmd_region;
>   	int num_regions;
>   
>   	struct channel_program	cp;
> @@ -116,6 +120,7 @@ enum vfio_ccw_event {
>   	VFIO_CCW_EVENT_NOT_OPER,
>   	VFIO_CCW_EVENT_IO_REQ,
>   	VFIO_CCW_EVENT_INTERRUPT,
> +	VFIO_CCW_EVENT_ASYNC_REQ,
>   	/* last element! */
>   	NR_VFIO_CCW_EVENTS
>   };
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index 56e2413d3e00..8f10748dac79 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -354,6 +354,8 @@ struct vfio_region_gfx_edid {
>   };
>   
>   #define VFIO_REGION_TYPE_CCW			(2)
> +/* ccw sub-types */
> +#define VFIO_REGION_SUBTYPE_CCW_ASYNC_CMD	(1)
>   
>   /*
>    * 10de vendor sub-type
> diff --git a/include/uapi/linux/vfio_ccw.h b/include/uapi/linux/vfio_ccw.h
> index 2ec5f367ff78..cbecbf0cd54f 100644
> --- a/include/uapi/linux/vfio_ccw.h
> +++ b/include/uapi/linux/vfio_ccw.h
> @@ -12,6 +12,7 @@
>   
>   #include <linux/types.h>
>   
> +/* used for START SUBCHANNEL, always present */
>   struct ccw_io_region {
>   #define ORB_AREA_SIZE 12
>   	__u8	orb_area[ORB_AREA_SIZE];
> @@ -22,4 +23,15 @@ struct ccw_io_region {
>   	__u32	ret_code;
>   } __packed;
>   
> +/*
> + * used for processing commands that trigger asynchronous actions
> + * Note: this is controlled by a capability
> + */
> +#define VFIO_CCW_ASYNC_CMD_HSCH (1 << 0)
> +#define VFIO_CCW_ASYNC_CMD_CSCH (1 << 1)
> +struct ccw_cmd_region {
> +	__u32 command;
> +	__u32 ret_code;
> +} __packed;
> +
>   #endif
>
Farhan Ali April 15, 2019, 3:25 p.m. UTC | #2
On 03/01/2019 04:39 AM, Cornelia Huck wrote:
> Add a region to the vfio-ccw device that can be used to submit
> asynchronous I/O instructions. ssch continues to be handled by the
> existing I/O region; the new region handles hsch and csch.
> 
> Interrupt status continues to be reported through the same channels
> as for ssch.
> 
> Signed-off-by: Cornelia Huck<cohuck@redhat.com>

Reviewed-by: Farhan Ali <alifm@linux.ibm.com>

Patch
diff mbox series

diff --git a/drivers/s390/cio/Makefile b/drivers/s390/cio/Makefile
index f230516abb96..f6a8db04177c 100644
--- a/drivers/s390/cio/Makefile
+++ b/drivers/s390/cio/Makefile
@@ -20,5 +20,6 @@  obj-$(CONFIG_CCWGROUP) += ccwgroup.o
 qdio-objs := qdio_main.o qdio_thinint.o qdio_debug.o qdio_setup.o
 obj-$(CONFIG_QDIO) += qdio.o
 
-vfio_ccw-objs += vfio_ccw_drv.o vfio_ccw_cp.o vfio_ccw_ops.o vfio_ccw_fsm.o
+vfio_ccw-objs += vfio_ccw_drv.o vfio_ccw_cp.o vfio_ccw_ops.o vfio_ccw_fsm.o \
+	vfio_ccw_async.o
 obj-$(CONFIG_VFIO_CCW) += vfio_ccw.o
diff --git a/drivers/s390/cio/vfio_ccw_async.c b/drivers/s390/cio/vfio_ccw_async.c
new file mode 100644
index 000000000000..8c1d2357ef5b
--- /dev/null
+++ b/drivers/s390/cio/vfio_ccw_async.c
@@ -0,0 +1,88 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Async I/O region for vfio_ccw
+ *
+ * Copyright Red Hat, Inc. 2019
+ *
+ * Author(s): Cornelia Huck <cohuck@redhat.com>
+ */
+
+#include <linux/vfio.h>
+#include <linux/mdev.h>
+
+#include "vfio_ccw_private.h"
+
+static ssize_t vfio_ccw_async_region_read(struct vfio_ccw_private *private,
+					  char __user *buf, size_t count,
+					  loff_t *ppos)
+{
+	unsigned int i = VFIO_CCW_OFFSET_TO_INDEX(*ppos) - VFIO_CCW_NUM_REGIONS;
+	loff_t pos = *ppos & VFIO_CCW_OFFSET_MASK;
+	struct ccw_cmd_region *region;
+	int ret;
+
+	if (pos + count > sizeof(*region))
+		return -EINVAL;
+
+	mutex_lock(&private->io_mutex);
+	region = private->region[i].data;
+	if (copy_to_user(buf, (void *)region + pos, count))
+		ret = -EFAULT;
+	else
+		ret = count;
+	mutex_unlock(&private->io_mutex);
+	return ret;
+}
+
+static ssize_t vfio_ccw_async_region_write(struct vfio_ccw_private *private,
+					   const char __user *buf, size_t count,
+					   loff_t *ppos)
+{
+	unsigned int i = VFIO_CCW_OFFSET_TO_INDEX(*ppos) - VFIO_CCW_NUM_REGIONS;
+	loff_t pos = *ppos & VFIO_CCW_OFFSET_MASK;
+	struct ccw_cmd_region *region;
+	int ret;
+
+	if (pos + count > sizeof(*region))
+		return -EINVAL;
+
+	if (!mutex_trylock(&private->io_mutex))
+		return -EAGAIN;
+
+	region = private->region[i].data;
+	if (copy_from_user((void *)region + pos, buf, count)) {
+		ret = -EFAULT;
+		goto out_unlock;
+	}
+
+	vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_ASYNC_REQ);
+
+	ret = region->ret_code ? region->ret_code : count;
+
+out_unlock:
+	mutex_unlock(&private->io_mutex);
+	return ret;
+}
+
+static void vfio_ccw_async_region_release(struct vfio_ccw_private *private,
+					  struct vfio_ccw_region *region)
+{
+
+}
+
+const struct vfio_ccw_regops vfio_ccw_async_region_ops = {
+	.read = vfio_ccw_async_region_read,
+	.write = vfio_ccw_async_region_write,
+	.release = vfio_ccw_async_region_release,
+};
+
+int vfio_ccw_register_async_dev_regions(struct vfio_ccw_private *private)
+{
+	return vfio_ccw_register_dev_region(private,
+					    VFIO_REGION_SUBTYPE_CCW_ASYNC_CMD,
+					    &vfio_ccw_async_region_ops,
+					    sizeof(struct ccw_cmd_region),
+					    VFIO_REGION_INFO_FLAG_READ |
+					    VFIO_REGION_INFO_FLAG_WRITE,
+					    private->cmd_region);
+}
diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index 5ea0da1dd954..c39d01943a6a 100644
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -3,9 +3,11 @@ 
  * VFIO based Physical Subchannel device driver
  *
  * Copyright IBM Corp. 2017
+ * Copyright Red Hat, Inc. 2019
  *
  * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
  *            Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
+ *            Cornelia Huck <cohuck@redhat.com>
  */
 
 #include <linux/module.h>
@@ -23,6 +25,7 @@ 
 
 struct workqueue_struct *vfio_ccw_work_q;
 static struct kmem_cache *vfio_ccw_io_region;
+static struct kmem_cache *vfio_ccw_cmd_region;
 
 /*
  * Helpers
@@ -110,7 +113,7 @@  static int vfio_ccw_sch_probe(struct subchannel *sch)
 {
 	struct pmcw *pmcw = &sch->schib.pmcw;
 	struct vfio_ccw_private *private;
-	int ret;
+	int ret = -ENOMEM;
 
 	if (pmcw->qf) {
 		dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
@@ -124,10 +127,13 @@  static int vfio_ccw_sch_probe(struct subchannel *sch)
 
 	private->io_region = kmem_cache_zalloc(vfio_ccw_io_region,
 					       GFP_KERNEL | GFP_DMA);
-	if (!private->io_region) {
-		kfree(private);
-		return -ENOMEM;
-	}
+	if (!private->io_region)
+		goto out_free;
+
+	private->cmd_region = kmem_cache_zalloc(vfio_ccw_cmd_region,
+						GFP_KERNEL | GFP_DMA);
+	if (!private->cmd_region)
+		goto out_free;
 
 	private->sch = sch;
 	dev_set_drvdata(&sch->dev, private);
@@ -155,7 +161,10 @@  static int vfio_ccw_sch_probe(struct subchannel *sch)
 	cio_disable_subchannel(sch);
 out_free:
 	dev_set_drvdata(&sch->dev, NULL);
-	kmem_cache_free(vfio_ccw_io_region, private->io_region);
+	if (private->cmd_region)
+		kmem_cache_free(vfio_ccw_cmd_region, private->cmd_region);
+	if (private->io_region)
+		kmem_cache_free(vfio_ccw_io_region, private->io_region);
 	kfree(private);
 	return ret;
 }
@@ -170,6 +179,7 @@  static int vfio_ccw_sch_remove(struct subchannel *sch)
 
 	dev_set_drvdata(&sch->dev, NULL);
 
+	kmem_cache_free(vfio_ccw_cmd_region, private->cmd_region);
 	kmem_cache_free(vfio_ccw_io_region, private->io_region);
 	kfree(private);
 
@@ -244,7 +254,7 @@  static struct css_driver vfio_ccw_sch_driver = {
 
 static int __init vfio_ccw_sch_init(void)
 {
-	int ret;
+	int ret = -ENOMEM;
 
 	vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
 	if (!vfio_ccw_work_q)
@@ -254,20 +264,30 @@  static int __init vfio_ccw_sch_init(void)
 					sizeof(struct ccw_io_region), 0,
 					SLAB_ACCOUNT, 0,
 					sizeof(struct ccw_io_region), NULL);
-	if (!vfio_ccw_io_region) {
-		destroy_workqueue(vfio_ccw_work_q);
-		return -ENOMEM;
-	}
+	if (!vfio_ccw_io_region)
+		goto out_err;
+
+	vfio_ccw_cmd_region = kmem_cache_create_usercopy("vfio_ccw_cmd_region",
+					sizeof(struct ccw_cmd_region), 0,
+					SLAB_ACCOUNT, 0,
+					sizeof(struct ccw_cmd_region), NULL);
+	if (!vfio_ccw_cmd_region)
+		goto out_err;
 
 	isc_register(VFIO_CCW_ISC);
 	ret = css_driver_register(&vfio_ccw_sch_driver);
 	if (ret) {
 		isc_unregister(VFIO_CCW_ISC);
-		kmem_cache_destroy(vfio_ccw_io_region);
-		destroy_workqueue(vfio_ccw_work_q);
+		goto out_err;
 	}
 
 	return ret;
+
+out_err:
+	kmem_cache_destroy(vfio_ccw_cmd_region);
+	kmem_cache_destroy(vfio_ccw_io_region);
+	destroy_workqueue(vfio_ccw_work_q);
+	return ret;
 }
 
 static void __exit vfio_ccw_sch_exit(void)
diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c
index b4a141fbd1a8..49d9d3da0282 100644
--- a/drivers/s390/cio/vfio_ccw_fsm.c
+++ b/drivers/s390/cio/vfio_ccw_fsm.c
@@ -3,8 +3,10 @@ 
  * Finite state machine for vfio-ccw device handling
  *
  * Copyright IBM Corp. 2017
+ * Copyright Red Hat, Inc. 2019
  *
  * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
+ *            Cornelia Huck <cohuck@redhat.com>
  */
 
 #include <linux/vfio.h>
@@ -73,6 +75,75 @@  static int fsm_io_helper(struct vfio_ccw_private *private)
 	return ret;
 }
 
+static int fsm_do_halt(struct vfio_ccw_private *private)
+{
+	struct subchannel *sch;
+	unsigned long flags;
+	int ccode;
+	int ret;
+
+	sch = private->sch;
+
+	spin_lock_irqsave(sch->lock, flags);
+
+	/* Issue "Halt Subchannel" */
+	ccode = hsch(sch->schid);
+
+	switch (ccode) {
+	case 0:
+		/*
+		 * Initialize device status information
+		 */
+		sch->schib.scsw.cmd.actl |= SCSW_ACTL_HALT_PEND;
+		ret = 0;
+		break;
+	case 1:		/* Status pending */
+	case 2:		/* Busy */
+		ret = -EBUSY;
+		break;
+	case 3:		/* Device not operational */
+		ret = -ENODEV;
+		break;
+	default:
+		ret = ccode;
+	}
+	spin_unlock_irqrestore(sch->lock, flags);
+	return ret;
+}
+
+static int fsm_do_clear(struct vfio_ccw_private *private)
+{
+	struct subchannel *sch;
+	unsigned long flags;
+	int ccode;
+	int ret;
+
+	sch = private->sch;
+
+	spin_lock_irqsave(sch->lock, flags);
+
+	/* Issue "Clear Subchannel" */
+	ccode = csch(sch->schid);
+
+	switch (ccode) {
+	case 0:
+		/*
+		 * Initialize device status information
+		 */
+		sch->schib.scsw.cmd.actl = SCSW_ACTL_CLEAR_PEND;
+		/* TODO: check what else we might need to clear */
+		ret = 0;
+		break;
+	case 3:		/* Device not operational */
+		ret = -ENODEV;
+		break;
+	default:
+		ret = ccode;
+	}
+	spin_unlock_irqrestore(sch->lock, flags);
+	return ret;
+}
+
 static void fsm_notoper(struct vfio_ccw_private *private,
 			enum vfio_ccw_event event)
 {
@@ -113,6 +184,24 @@  static void fsm_io_retry(struct vfio_ccw_private *private,
 	private->io_region->ret_code = -EAGAIN;
 }
 
+static void fsm_async_error(struct vfio_ccw_private *private,
+			    enum vfio_ccw_event event)
+{
+	struct ccw_cmd_region *cmd_region = private->cmd_region;
+
+	pr_err("vfio-ccw: FSM: %s request from state:%d\n",
+	       cmd_region->command == VFIO_CCW_ASYNC_CMD_HSCH ? "halt" :
+	       cmd_region->command == VFIO_CCW_ASYNC_CMD_CSCH ? "clear" :
+	       "<unknown>", private->state);
+	cmd_region->ret_code = -EIO;
+}
+
+static void fsm_async_retry(struct vfio_ccw_private *private,
+			    enum vfio_ccw_event event)
+{
+	private->cmd_region->ret_code = -EAGAIN;
+}
+
 static void fsm_disabled_irq(struct vfio_ccw_private *private,
 			     enum vfio_ccw_event event)
 {
@@ -176,11 +265,11 @@  static void fsm_io_request(struct vfio_ccw_private *private,
 		}
 		return;
 	} else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) {
-		/* XXX: Handle halt. */
+		/* halt is handled via the async cmd region */
 		io_region->ret_code = -EOPNOTSUPP;
 		goto err_out;
 	} else if (scsw->cmd.fctl & SCSW_FCTL_CLEAR_FUNC) {
-		/* XXX: Handle clear. */
+		/* clear is handled via the async cmd region */
 		io_region->ret_code = -EOPNOTSUPP;
 		goto err_out;
 	}
@@ -190,6 +279,27 @@  static void fsm_io_request(struct vfio_ccw_private *private,
 			       io_region->ret_code, errstr);
 }
 
+/*
+ * Deal with an async request from userspace.
+ */
+static void fsm_async_request(struct vfio_ccw_private *private,
+			      enum vfio_ccw_event event)
+{
+	struct ccw_cmd_region *cmd_region = private->cmd_region;
+
+	switch (cmd_region->command) {
+	case VFIO_CCW_ASYNC_CMD_HSCH:
+		cmd_region->ret_code = fsm_do_halt(private);
+		break;
+	case VFIO_CCW_ASYNC_CMD_CSCH:
+		cmd_region->ret_code = fsm_do_clear(private);
+		break;
+	default:
+		/* should not happen? */
+		cmd_region->ret_code = -EINVAL;
+	}
+}
+
 /*
  * Got an interrupt for a normal io (state busy).
  */
@@ -213,26 +323,31 @@  fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
 	[VFIO_CCW_STATE_NOT_OPER] = {
 		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_nop,
 		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_error,
+		[VFIO_CCW_EVENT_ASYNC_REQ]	= fsm_async_error,
 		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_disabled_irq,
 	},
 	[VFIO_CCW_STATE_STANDBY] = {
 		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_notoper,
 		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_error,
+		[VFIO_CCW_EVENT_ASYNC_REQ]	= fsm_async_error,
 		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_irq,
 	},
 	[VFIO_CCW_STATE_IDLE] = {
 		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_notoper,
 		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_request,
+		[VFIO_CCW_EVENT_ASYNC_REQ]	= fsm_async_request,
 		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_irq,
 	},
 	[VFIO_CCW_STATE_CP_PROCESSING] = {
 		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_notoper,
 		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_retry,
+		[VFIO_CCW_EVENT_ASYNC_REQ]	= fsm_async_retry,
 		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_irq,
 	},
 	[VFIO_CCW_STATE_CP_PENDING] = {
 		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_notoper,
 		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_busy,
+		[VFIO_CCW_EVENT_ASYNC_REQ]	= fsm_async_request,
 		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_irq,
 	},
 };
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 3fd663320bbf..ec2f796c70fe 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -149,11 +149,20 @@  static int vfio_ccw_mdev_open(struct mdev_device *mdev)
 	struct vfio_ccw_private *private =
 		dev_get_drvdata(mdev_parent_dev(mdev));
 	unsigned long events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
+	int ret;
 
 	private->nb.notifier_call = vfio_ccw_mdev_notifier;
 
-	return vfio_register_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
-				      &events, &private->nb);
+	ret = vfio_register_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
+				     &events, &private->nb);
+	if (ret)
+		return ret;
+
+	ret = vfio_ccw_register_async_dev_regions(private);
+	if (ret)
+		vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
+					 &private->nb);
+	return ret;
 }
 
 static void vfio_ccw_mdev_release(struct mdev_device *mdev)
diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
index d888a2573470..f1092c3dc1b1 100644
--- a/drivers/s390/cio/vfio_ccw_private.h
+++ b/drivers/s390/cio/vfio_ccw_private.h
@@ -53,6 +53,8 @@  int vfio_ccw_register_dev_region(struct vfio_ccw_private *private,
 				 const struct vfio_ccw_regops *ops,
 				 size_t size, u32 flags, void *data);
 
+int vfio_ccw_register_async_dev_regions(struct vfio_ccw_private *private);
+
 /**
  * struct vfio_ccw_private
  * @sch: pointer to the subchannel
@@ -64,6 +66,7 @@  int vfio_ccw_register_dev_region(struct vfio_ccw_private *private,
  * @io_region: MMIO region to input/output I/O arguments/results
  * @io_mutex: protect against concurrent update of I/O regions
  * @region: additional regions for other subchannel operations
+ * @cmd_region: MMIO region for asynchronous I/O commands other than START
  * @num_regions: number of additional regions
  * @cp: channel program for the current I/O operation
  * @irb: irb info received from interrupt
@@ -81,6 +84,7 @@  struct vfio_ccw_private {
 	struct ccw_io_region	*io_region;
 	struct mutex		io_mutex;
 	struct vfio_ccw_region *region;
+	struct ccw_cmd_region	*cmd_region;
 	int num_regions;
 
 	struct channel_program	cp;
@@ -116,6 +120,7 @@  enum vfio_ccw_event {
 	VFIO_CCW_EVENT_NOT_OPER,
 	VFIO_CCW_EVENT_IO_REQ,
 	VFIO_CCW_EVENT_INTERRUPT,
+	VFIO_CCW_EVENT_ASYNC_REQ,
 	/* last element! */
 	NR_VFIO_CCW_EVENTS
 };
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 56e2413d3e00..8f10748dac79 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -354,6 +354,8 @@  struct vfio_region_gfx_edid {
 };
 
 #define VFIO_REGION_TYPE_CCW			(2)
+/* ccw sub-types */
+#define VFIO_REGION_SUBTYPE_CCW_ASYNC_CMD	(1)
 
 /*
  * 10de vendor sub-type
diff --git a/include/uapi/linux/vfio_ccw.h b/include/uapi/linux/vfio_ccw.h
index 2ec5f367ff78..cbecbf0cd54f 100644
--- a/include/uapi/linux/vfio_ccw.h
+++ b/include/uapi/linux/vfio_ccw.h
@@ -12,6 +12,7 @@ 
 
 #include <linux/types.h>
 
+/* used for START SUBCHANNEL, always present */
 struct ccw_io_region {
 #define ORB_AREA_SIZE 12
 	__u8	orb_area[ORB_AREA_SIZE];
@@ -22,4 +23,15 @@  struct ccw_io_region {
 	__u32	ret_code;
 } __packed;
 
+/*
+ * used for processing commands that trigger asynchronous actions
+ * Note: this is controlled by a capability
+ */
+#define VFIO_CCW_ASYNC_CMD_HSCH (1 << 0)
+#define VFIO_CCW_ASYNC_CMD_CSCH (1 << 1)
+struct ccw_cmd_region {
+	__u32 command;
+	__u32 ret_code;
+} __packed;
+
 #endif