From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Reply-To: pmorel@linux.ibm.com Subject: Re: [PATCH 09/10] virtio/s390: use DMA memory for ccw I/O and classic notifiers References: <20190426183245.37939-1-pasic@linux.ibm.com> <20190426183245.37939-10-pasic@linux.ibm.com> From: Pierre Morel Date: Wed, 8 May 2019 16:46:12 +0200 MIME-Version: 1.0 In-Reply-To: <20190426183245.37939-10-pasic@linux.ibm.com> Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Language: en-US Content-Transfer-Encoding: 8bit Message-Id: 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: > Before virtio-ccw could get away with not using DMA API for the pieces of > memory it does ccw I/O with. With protected virtualization this has to > change, since the hypervisor needs to read and sometimes also write these > pieces of memory. > > The hypervisor is supposed to poke the classic notifiers, if these are > used, out of band with regards to ccw I/O. So these need to be allocated > as DMA memory (which is shared memory for protected virtualization > guests). > > Let us factor out everything from struct virtio_ccw_device that needs to > be DMA memory in a satellite that is allocated as such. > > Note: The control blocks of I/O instructions do not need to be shared. > These are marshalled by the ultravisor. > > Signed-off-by: Halil Pasic > --- > drivers/s390/virtio/virtio_ccw.c | 177 +++++++++++++++++++++------------------ > 1 file changed, 96 insertions(+), 81 deletions(-) > > diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c > index 1f3e7d56924f..613b18001a0c 100644 > --- a/drivers/s390/virtio/virtio_ccw.c > +++ b/drivers/s390/virtio/virtio_ccw.c > @@ -46,9 +46,15 @@ struct vq_config_block { > #define VIRTIO_CCW_CONFIG_SIZE 0x100 > /* same as PCI config space size, should be enough for all drivers */ > > +struct vcdev_dma_area { > + unsigned long indicators; > + unsigned long indicators2; > + struct vq_config_block config_block; > + __u8 status; > +}; > + > struct virtio_ccw_device { > struct virtio_device vdev; > - __u8 *status; > __u8 config[VIRTIO_CCW_CONFIG_SIZE]; > struct ccw_device *cdev; > __u32 curr_io; > @@ -58,24 +64,22 @@ struct virtio_ccw_device { > spinlock_t lock; > struct mutex io_lock; /* Serializes I/O requests */ > struct list_head virtqueues; > - unsigned long indicators; > - unsigned long indicators2; > - struct vq_config_block *config_block; > bool is_thinint; > bool going_away; > bool device_lost; > unsigned int config_ready; > void *airq_info; > + struct vcdev_dma_area *dma_area; > }; > > static inline unsigned long *indicators(struct virtio_ccw_device *vcdev) > { > - return &vcdev->indicators; > + return &vcdev->dma_area->indicators; > } > > static inline unsigned long *indicators2(struct virtio_ccw_device *vcdev) > { > - return &vcdev->indicators2; > + return &vcdev->dma_area->indicators2; > } > > struct vq_info_block_legacy { > @@ -176,6 +180,22 @@ static struct virtio_ccw_device *to_vc_device(struct virtio_device *vdev) > return container_of(vdev, struct virtio_ccw_device, vdev); > } > > +static inline void *__vc_dma_alloc(struct virtio_device *vdev, size_t size) > +{ > + return ccw_device_dma_zalloc(to_vc_device(vdev)->cdev, size); > +} > + > +static inline void __vc_dma_free(struct virtio_device *vdev, size_t size, > + void *cpu_addr) > +{ > + return ccw_device_dma_free(to_vc_device(vdev)->cdev, cpu_addr, size); > +} > + > +#define vc_dma_alloc_struct(vdev, ptr) \ > + ({ptr = __vc_dma_alloc(vdev, sizeof(*(ptr))); }) > +#define vc_dma_free_struct(vdev, ptr) \ > + __vc_dma_free(vdev, sizeof(*(ptr)), (ptr)) > + > static void drop_airq_indicator(struct virtqueue *vq, struct airq_info *info) > { > unsigned long i, flags; > @@ -335,8 +355,7 @@ static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev, > struct airq_info *airq_info = vcdev->airq_info; > > if (vcdev->is_thinint) { > - thinint_area = kzalloc(sizeof(*thinint_area), > - GFP_DMA | GFP_KERNEL); > + vc_dma_alloc_struct(&vcdev->vdev, thinint_area); > if (!thinint_area) > return; > thinint_area->summary_indicator = > @@ -347,8 +366,8 @@ static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev, > ccw->cda = (__u32)(unsigned long) thinint_area; > } else { > /* payload is the address of the indicators */ > - indicatorp = kmalloc(sizeof(indicators(vcdev)), > - GFP_DMA | GFP_KERNEL); > + indicatorp = __vc_dma_alloc(&vcdev->vdev, > + sizeof(indicators(vcdev))); should be sizeof(long) ? This is a recurrent error, but it is not an issue because the size of the indicators is unsigned long as the size of the pointer. Regards, Pierre -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany