From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Reply-To: pmorel@linux.ibm.com Subject: Re: [PATCH 10/10] virtio/s390: make airq summary indicators DMA References: <20190426183245.37939-1-pasic@linux.ibm.com> <20190426183245.37939-11-pasic@linux.ibm.com> From: Pierre Morel Date: Wed, 8 May 2019 17:11:14 +0200 MIME-Version: 1.0 In-Reply-To: <20190426183245.37939-11-pasic@linux.ibm.com> Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Language: en-US Content-Transfer-Encoding: 8bit Message-Id: <74ff9a63-891a-7e24-0865-8cc91a95cada@linux.ibm.com> Sender: kvm-owner@vger.kernel.org List-Archive: List-Post: To: Halil Pasic , kvm@vger.kernel.org, linux-s390@vger.kernel.org, Cornelia Huck , Martin Schwidefsky , Sebastian Ott Cc: virtualization@lists.linux-foundation.org, "Michael S. Tsirkin" , Christoph Hellwig , Thomas Huth , Christian Borntraeger , Viktor Mihajlovski , Vasily Gorbik , Janosch Frank , Claudio Imbrenda , Farhan Ali , Eric Farman List-ID: 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 > --- > 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