Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757670AbaJaS7X (ORCPT ); Fri, 31 Oct 2014 14:59:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34569 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751746AbaJaS7V (ORCPT ); Fri, 31 Oct 2014 14:59:21 -0400 Message-ID: <1414781936.27420.317.camel@ul30vt.home> Subject: Re: [PATCH v9 07/19] vfio/platform: return info for device memory mapped IO regions From: Alex Williamson To: Antonios Motakis Cc: kvmarm@lists.cs.columbia.edu, iommu@lists.linux-foundation.org, will.deacon@arm.com, tech@virtualopensystems.com, christoffer.dall@linaro.org, eric.auger@linaro.org, kim.phillips@freescale.com, marc.zyngier@arm.com, "open list:VFIO DRIVER" , open list Date: Fri, 31 Oct 2014 12:58:56 -0600 In-Reply-To: <1414433284-31719-8-git-send-email-a.motakis@virtualopensystems.com> References: <1414433284-31719-1-git-send-email-a.motakis@virtualopensystems.com> <1414433284-31719-8-git-send-email-a.motakis@virtualopensystems.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2014-10-27 at 19:07 +0100, Antonios Motakis wrote: > This patch enables the IOCTLs VFIO_DEVICE_GET_REGION_INFO ioctl call, > which allows the user to learn about the available MMIO resources of > a device. > > Signed-off-by: Antonios Motakis > --- > drivers/vfio/platform/vfio_platform_common.c | 110 +++++++++++++++++++++++++- > drivers/vfio/platform/vfio_platform_private.h | 22 ++++++ > 2 files changed, 128 insertions(+), 4 deletions(-) > > diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c > index cb20526..82de752 100644 > --- a/drivers/vfio/platform/vfio_platform_common.c > +++ b/drivers/vfio/platform/vfio_platform_common.c > @@ -27,17 +27,97 @@ > > #include "vfio_platform_private.h" > > +static DEFINE_MUTEX(driver_lock); > + > +static int vfio_platform_regions_init(struct vfio_platform_device *vdev) > +{ > + int cnt = 0, i; > + > + while (vdev->get_resource(vdev, cnt)) > + cnt++; > + > + vdev->regions = kcalloc(cnt, sizeof(struct vfio_platform_region), > + GFP_KERNEL); > + if (!vdev->regions) > + return -ENOMEM; > + > + for (i = 0; i < cnt; i++) { > + struct resource *res = > + vdev->get_resource(vdev, i); > + > + if (!res) > + goto err; > + > + vdev->regions[i].addr = res->start; > + vdev->regions[i].size = resource_size(res); > + vdev->regions[i].flags = 0; > + > + switch (resource_type(res)) { > + case IORESOURCE_MEM: > + vdev->regions[i].type = VFIO_PLATFORM_REGION_TYPE_MMIO; > + break; > + case IORESOURCE_IO: > + vdev->regions[i].type = VFIO_PLATFORM_REGION_TYPE_PIO; > + break; > + default: > + goto err; > + } > + } > + > + vdev->num_regions = cnt; > + > + return 0; > +err: > + kfree(vdev->regions); > + return -EINVAL; > +} > + > +static void vfio_platform_regions_cleanup(struct vfio_platform_device *vdev) > +{ > + vdev->num_regions = 0; > + kfree(vdev->regions); > +} > + > static void vfio_platform_release(void *device_data) > { > + struct vfio_platform_device *vdev = device_data; > + > + mutex_lock(&driver_lock); > + > + if (!(--vdev->refcnt)) { > + vfio_platform_regions_cleanup(vdev); > + } > + > + mutex_unlock(&driver_lock); > + > module_put(THIS_MODULE); > } > > static int vfio_platform_open(void *device_data) > { > + struct vfio_platform_device *vdev = device_data; > + int ret; > + > if (!try_module_get(THIS_MODULE)) > return -ENODEV; > > + mutex_lock(&driver_lock); > + > + if (!vdev->refcnt) { > + ret = vfio_platform_regions_init(vdev); > + if (ret) > + goto err_reg; > + } > + > + vdev->refcnt++; > + > + mutex_unlock(&driver_lock); > return 0; > + > +err_reg: > + mutex_unlock(&driver_lock); > + module_put(THIS_MODULE); > + return ret; > } > > static long vfio_platform_ioctl(void *device_data, > @@ -58,15 +138,33 @@ static long vfio_platform_ioctl(void *device_data, > return -EINVAL; > > info.flags = vdev->flags; > - info.num_regions = 0; > + info.num_regions = vdev->num_regions; > info.num_irqs = 0; > > return copy_to_user((void __user *)arg, &info, minsz); > > - } else if (cmd == VFIO_DEVICE_GET_REGION_INFO) > - return -EINVAL; > + } else if (cmd == VFIO_DEVICE_GET_REGION_INFO) { > + struct vfio_region_info info; > + > + minsz = offsetofend(struct vfio_region_info, offset); > + > + if (copy_from_user(&info, (void __user *)arg, minsz)) > + return -EFAULT; > > - else if (cmd == VFIO_DEVICE_GET_IRQ_INFO) > + if (info.argsz < minsz) > + return -EINVAL; > + > + if (info.index >= vdev->num_regions) > + return -EINVAL; > + > + /* map offset to the physical address */ > + info.offset = VFIO_PLATFORM_INDEX_TO_OFFSET(info.index); > + info.size = vdev->regions[info.index].size; > + info.flags = vdev->regions[info.index].flags; > + > + return copy_to_user((void __user *)arg, &info, minsz); > + > + } else if (cmd == VFIO_DEVICE_GET_IRQ_INFO) > return -EINVAL; > > else if (cmd == VFIO_DEVICE_SET_IRQS) > @@ -134,10 +232,14 @@ struct vfio_platform_device *vfio_platform_remove_common(struct device *dev) > { > struct vfio_platform_device *vdev; > > + mutex_lock(&driver_lock); > + > vdev = vfio_del_group_dev(dev); > if (vdev) > iommu_group_put(dev->iommu_group); > > + mutex_unlock(&driver_lock); > + This is the same deadlock that vfio-pci recently removed. Imagine that you attempt to unbind an in-use device from vfio-platform, vfio_del_group_dev() waits, holding the mutex, for the device to be unused. vfio_platform_release() must acquire the mutex before it can run. I don't think you need the mutex here. Thanks, Alex > return vdev; > } > EXPORT_SYMBOL_GPL(vfio_platform_remove_common); > diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h > index 062b92d..b24729f 100644 > --- a/drivers/vfio/platform/vfio_platform_private.h > +++ b/drivers/vfio/platform/vfio_platform_private.h > @@ -15,7 +15,29 @@ > #ifndef VFIO_PLATFORM_PRIVATE_H > #define VFIO_PLATFORM_PRIVATE_H > > +#define VFIO_PLATFORM_OFFSET_SHIFT 40 > +#define VFIO_PLATFORM_OFFSET_MASK (((u64)(1) << VFIO_PLATFORM_OFFSET_SHIFT) - 1) > + > +#define VFIO_PLATFORM_OFFSET_TO_INDEX(off) \ > + (off >> VFIO_PLATFORM_OFFSET_SHIFT) > + > +#define VFIO_PLATFORM_INDEX_TO_OFFSET(index) \ > + ((u64)(index) << VFIO_PLATFORM_OFFSET_SHIFT) > + > +struct vfio_platform_region { > + u64 addr; > + resource_size_t size; > + u32 flags; > + u32 type; > +#define VFIO_PLATFORM_REGION_TYPE_MMIO 1 > +#define VFIO_PLATFORM_REGION_TYPE_PIO 2 > +}; > + > struct vfio_platform_device { > + struct vfio_platform_region *regions; > + u32 num_regions; > + int refcnt; > + > /* > * These fields should be filled by the bus specific binder > */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/