[v3,8/8] virtio/s390: make airq summary indicators DMA

Commit Message

Michael Mueller May 29, 2019, 12:26 p.m. UTC

From: Halil Pasic <[e-mail]>

Hypervisor needs to interact with the summary indicators, so these
need to be DMA memory as well (at least for protected virtualization
guests).

Signed-off-by: Halil Pasic <[e-mail]>
Signed-off-by: Michael Mueller <[e-mail]>
---
 drivers/s390/virtio/virtio_ccw.c | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

Comments

Cornelia Huck June 3, 2019, 4:03 p.m. UTC | #1

On Wed, 29 May 2019 14:26:57 +0200
Michael Mueller <[e-mail]> wrote:

> From: Halil Pasic <[e-mail]>
> 
> Hypervisor needs to interact with the summary indicators, so these
> need to be DMA memory as well (at least for protected virtualization
> guests).
> 
> Signed-off-by: Halil Pasic <[e-mail]>
> Signed-off-by: Michael Mueller <[e-mail]>
> ---
>  drivers/s390/virtio/virtio_ccw.c | 26 +++++++++++++++++++-------
>  1 file changed, 19 insertions(+), 7 deletions(-)

(...)

> @@ -1501,6 +1508,11 @@ static int __init virtio_ccw_init(void)
>  {
>  	/* parse no_auto string before we do anything further */
>  	no_auto_parse();
> +
> +	summary_indicators = cio_dma_zalloc(MAX_AIRQ_AREAS);
> +	if (!summary_indicators)
> +		return -ENOMEM;
> +
>  	return ccw_driver_register(&virtio_ccw_driver);

Don't you need to free summary_indicators again if registering the
driver fails?

>  }
>  device_initcall(virtio_ccw_init);

Halil Pasic June 3, 2019, 5:54 p.m. UTC | #2

On Mon, 3 Jun 2019 18:03:37 +0200
Cornelia Huck <[e-mail]> wrote:

> On Wed, 29 May 2019 14:26:57 +0200
> Michael Mueller <[e-mail]> wrote:
> 
> > From: Halil Pasic <[e-mail]>
> > 
> > Hypervisor needs to interact with the summary indicators, so these
> > need to be DMA memory as well (at least for protected virtualization
> > guests).
> > 
> > Signed-off-by: Halil Pasic <[e-mail]>
> > Signed-off-by: Michael Mueller <[e-mail]>
> > ---
> >  drivers/s390/virtio/virtio_ccw.c | 26 +++++++++++++++++++-------
> >  1 file changed, 19 insertions(+), 7 deletions(-)
> 
> (...)
> 
> > @@ -1501,6 +1508,11 @@ static int __init virtio_ccw_init(void)
> >  {
> >  	/* parse no_auto string before we do anything further */
> >  	no_auto_parse();
> > +
> > +	summary_indicators = cio_dma_zalloc(MAX_AIRQ_AREAS);
> > +	if (!summary_indicators)
> > +		return -ENOMEM;
> > +
> >  	return ccw_driver_register(&virtio_ccw_driver);
> 
> Don't you need to free summary_indicators again if registering the
> driver fails?
> 

We do! BTW as of today I'm back and I intend to handle things
regularly form now on ;).

Regards,
Halil

> >  }
> >  device_initcall(virtio_ccw_init);
>

Patch

diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index 03c9f7001fb1..efebd6dcd124 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -140,11 +140,17 @@  static int virtio_ccw_use_airq = 1;
 
 struct airq_info {
 	rwlock_t lock;
-	u8 summary_indicator;
+	u8 summary_indicator_idx;
 	struct airq_struct airq;
 	struct airq_iv *aiv;
 };
 static struct airq_info *airq_areas[MAX_AIRQ_AREAS];
+static u8 *summary_indicators;
+
+static inline u8 *get_summary_indicator(struct airq_info *info)
+{
+	return summary_indicators + info->summary_indicator_idx;
+}
 
 #define CCW_CMD_SET_VQ 0x13
 #define CCW_CMD_VDEV_RESET 0x33
@@ -225,7 +231,7 @@  static void virtio_airq_handler(struct airq_struct *airq, bool floating)
 			break;
 		vring_interrupt(0, (void *)airq_iv_get_ptr(info->aiv, ai));
 	}
-	info->summary_indicator = 0;
+	*(get_summary_indicator(info)) = 0;
 	smp_wmb();
 	/* Walk through indicators field, summary indicator not active. */
 	for (ai = 0;;) {
@@ -237,7 +243,7 @@  static void virtio_airq_handler(struct airq_struct *airq, bool floating)
 	read_unlock(&info->lock);
 }
 
-static struct airq_info *new_airq_info(void)
+static struct airq_info *new_airq_info(int index)
 {
 	struct airq_info *info;
 	int rc;
@@ -253,7 +259,8 @@  static struct airq_info *new_airq_info(void)
 		return NULL;
 	}
 	info->airq.handler = virtio_airq_handler;
-	info->airq.lsi_ptr = &info->summary_indicator;
+	info->summary_indicator_idx = index;
+	info->airq.lsi_ptr = get_summary_indicator(info);
 	info->airq.lsi_mask = 0xff;
 	info->airq.isc = VIRTIO_AIRQ_ISC;
 	rc = register_adapter_interrupt(&info->airq);
@@ -275,7 +282,7 @@  static unsigned long get_airq_indicator(struct virtqueue *vqs[], int nvqs,
 
 	for (i = 0; i < MAX_AIRQ_AREAS && !indicator_addr; i++) {
 		if (!airq_areas[i])
-			airq_areas[i] = new_airq_info();
+			airq_areas[i] = new_airq_info(i);
 		info = airq_areas[i];
 		if (!info)
 			return 0;
@@ -360,7 +367,7 @@  static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev,
 		if (!thinint_area)
 			return;
 		thinint_area->summary_indicator =
-			(unsigned long) &airq_info->summary_indicator;
+			(unsigned long) get_summary_indicator(airq_info);
 		thinint_area->isc = VIRTIO_AIRQ_ISC;
 		ccw->cmd_code = CCW_CMD_SET_IND_ADAPTER;
 		ccw->count = sizeof(*thinint_area);
@@ -625,7 +632,7 @@  static int virtio_ccw_register_adapter_ind(struct virtio_ccw_device *vcdev,
 	}
 	info = vcdev->airq_info;
 	thinint_area->summary_indicator =
-		(unsigned long) &info->summary_indicator;
+		(unsigned long) get_summary_indicator(info);
 	thinint_area->isc = VIRTIO_AIRQ_ISC;
 	ccw->cmd_code = CCW_CMD_SET_IND_ADAPTER;
 	ccw->flags = CCW_FLAG_SLI;
@@ -1501,6 +1508,11 @@  static int __init virtio_ccw_init(void)
 {
 	/* parse no_auto string before we do anything further */
 	no_auto_parse();
+
+	summary_indicators = cio_dma_zalloc(MAX_AIRQ_AREAS);
+	if (!summary_indicators)
+		return -ENOMEM;
+
 	return ccw_driver_register(&virtio_ccw_driver);
 }
 device_initcall(virtio_ccw_init);