On 26/04/2019 20:32, Halil Pasic wrote:
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 <pasic@xxxxxxxxxxxxx>
---
drivers/s390/virtio/virtio_ccw.c | 24 +++++++++++++++++-------
1 file changed, 17 insertions(+), 7 deletions(-)
diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index 613b18001a0c..6058b07fea08 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)
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 +243,8 @@ static void virtio_airq_handler(struct airq_struct *airq)
read_unlock(&info->lock);
}
-static struct airq_info *new_airq_info(void)
+/* call with airq_areas_lock held */
+static struct airq_info *new_airq_info(int index)
{
struct airq_info *info;
int rc;
@@ -252,7 +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);
@@ -273,8 +281,9 @@ static unsigned long get_airq_indicator(struct virtqueue *vqs[], int nvqs,
unsigned long bit, flags;
for (i = 0; i < MAX_AIRQ_AREAS && !indicator_addr; i++) {
+ /* TODO: this seems to be racy */
yes, my opinions too, was already racy, in my opinion, we need another
patch in another series to fix this.
However, not sure about the comment.
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;
@@ -359,7 +368,7 @@ 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);
@@ -624,7 +633,7 @@ 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;
@@ -1500,6 +1509,7 @@ 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);
return ccw_driver_register(&virtio_ccw_driver);
}
device_initcall(virtio_ccw_init);
--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany
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