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Sat, 10 Oct 2020 17:12:56 +0000 (UTC) Received: from [10.36.113.210] (ovpn-113-210.ams2.redhat.com [10.36.113.210]) by smtp.corp.redhat.com (Postfix) with ESMTPS id DD4B810013D0; Sat, 10 Oct 2020 17:12:51 +0000 (UTC) Subject: Re: [PATCH v6 05/10] vfio/fsl-mc: Allow userspace to MMAP fsl-mc device MMIO regions To: Diana Craciun , Alex Williamson , kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, bharatb.linux@gmail.com, laurentiu.tudor@nxp.com, Bharat Bhushan References: <20201005173654.31773-1-diana.craciun@oss.nxp.com> <20201005173654.31773-6-diana.craciun@oss.nxp.com> From: Auger Eric Message-ID: <90a72cfc-82eb-b867-e23a-7f363499d641@redhat.com> Date: Sat, 10 Oct 2020 19:12:50 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20201005173654.31773-6-diana.craciun@oss.nxp.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Hi Diana, On 10/5/20 7:36 PM, Diana Craciun wrote: > Allow userspace to mmap device regions for direct access of > fsl-mc devices. > > Signed-off-by: Bharat Bhushan > Signed-off-by: Diana Craciun Reviewed-by: Eric Auger Thanks Eric > --- > drivers/vfio/fsl-mc/vfio_fsl_mc.c | 68 ++++++++++++++++++++++++++++++- > 1 file changed, 66 insertions(+), 2 deletions(-) > > diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc.c b/drivers/vfio/fsl-mc/vfio_fsl_mc.c > index 05dace5ddc2c..55190a2730fb 100644 > --- a/drivers/vfio/fsl-mc/vfio_fsl_mc.c > +++ b/drivers/vfio/fsl-mc/vfio_fsl_mc.c > @@ -30,11 +30,20 @@ static int vfio_fsl_mc_regions_init(struct vfio_fsl_mc_device *vdev) > > for (i = 0; i < count; i++) { > struct resource *res = &mc_dev->regions[i]; > + int no_mmap = is_fsl_mc_bus_dprc(mc_dev); > > vdev->regions[i].addr = res->start; > vdev->regions[i].size = resource_size(res); > - vdev->regions[i].flags = 0; > vdev->regions[i].type = mc_dev->regions[i].flags & IORESOURCE_BITS; > + /* > + * Only regions addressed with PAGE granularity may be > + * MMAPed securely. > + */ > + if (!no_mmap && !(vdev->regions[i].addr & ~PAGE_MASK) && > + !(vdev->regions[i].size & ~PAGE_MASK)) > + vdev->regions[i].flags |= > + VFIO_REGION_INFO_FLAG_MMAP; > + > } > > return 0; > @@ -163,9 +172,64 @@ static ssize_t vfio_fsl_mc_write(void *device_data, const char __user *buf, > return -EINVAL; > } > > +static int vfio_fsl_mc_mmap_mmio(struct vfio_fsl_mc_region region, > + struct vm_area_struct *vma) > +{ > + u64 size = vma->vm_end - vma->vm_start; > + u64 pgoff, base; > + u8 region_cacheable; > + > + pgoff = vma->vm_pgoff & > + ((1U << (VFIO_FSL_MC_OFFSET_SHIFT - PAGE_SHIFT)) - 1); > + base = pgoff << PAGE_SHIFT; > + > + if (region.size < PAGE_SIZE || base + size > region.size) > + return -EINVAL; > + > + region_cacheable = (region.type & FSL_MC_REGION_CACHEABLE) && > + (region.type & FSL_MC_REGION_SHAREABLE); > + if (!region_cacheable) > + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); > + > + vma->vm_pgoff = (region.addr >> PAGE_SHIFT) + pgoff; > + > + return remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, > + size, vma->vm_page_prot); > +} > + > static int vfio_fsl_mc_mmap(void *device_data, struct vm_area_struct *vma) > { > - return -EINVAL; > + struct vfio_fsl_mc_device *vdev = device_data; > + struct fsl_mc_device *mc_dev = vdev->mc_dev; > + int index; > + > + index = vma->vm_pgoff >> (VFIO_FSL_MC_OFFSET_SHIFT - PAGE_SHIFT); > + > + if (vma->vm_end < vma->vm_start) > + return -EINVAL; > + if (vma->vm_start & ~PAGE_MASK) > + return -EINVAL; > + if (vma->vm_end & ~PAGE_MASK) > + return -EINVAL; > + if (!(vma->vm_flags & VM_SHARED)) > + return -EINVAL; > + if (index >= mc_dev->obj_desc.region_count) > + return -EINVAL; > + > + if (!(vdev->regions[index].flags & VFIO_REGION_INFO_FLAG_MMAP)) > + return -EINVAL; > + > + if (!(vdev->regions[index].flags & VFIO_REGION_INFO_FLAG_READ) > + && (vma->vm_flags & VM_READ)) > + return -EINVAL; > + > + if (!(vdev->regions[index].flags & VFIO_REGION_INFO_FLAG_WRITE) > + && (vma->vm_flags & VM_WRITE)) > + return -EINVAL; > + > + vma->vm_private_data = mc_dev; > + > + return vfio_fsl_mc_mmap_mmio(vdev->regions[index], vma); > } > > static const struct vfio_device_ops vfio_fsl_mc_ops = { >