RE: [PATCH v3 01/14] vfio/type1: Refactor vfio_iommu_type1_ioctl()

[Liu, Yi L]

> From: Alex Williamson <alex.williamson@xxxxxxxxxx>
> Sent: Friday, July 3, 2020 5:21 AM
> To: Liu, Yi L <yi.l.liu@xxxxxxxxx>
> 
> On Wed, 24 Jun 2020 01:55:14 -0700
> Liu Yi L <yi.l.liu@xxxxxxxxx> wrote:
> 
> > This patch refactors the vfio_iommu_type1_ioctl() to use switch
> > instead of if-else, and each cmd got a helper function.
> >
> > Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
> > CC: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> > Cc: Alex Williamson <alex.williamson@xxxxxxxxxx>
> > Cc: Eric Auger <eric.auger@xxxxxxxxxx>
> > Cc: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
> > Cc: Joerg Roedel <joro@xxxxxxxxxx>
> > Cc: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> > Suggested-by: Christoph Hellwig <hch@xxxxxxxxxxxxx>
> > Signed-off-by: Liu Yi L <yi.l.liu@xxxxxxxxx>
> > ---
> >  drivers/vfio/vfio_iommu_type1.c | 392
> > ++++++++++++++++++++++------------------
> >  1 file changed, 213 insertions(+), 179 deletions(-)
> 
> I can go ahead and grab this one for my v5.9 next branch.  Thanks,

thanks, that would be great help. I'll monitor your next branch on github.

Regards,
Yi Liu

> Alex
> 
> > diff --git a/drivers/vfio/vfio_iommu_type1.c
> > b/drivers/vfio/vfio_iommu_type1.c index 5e556ac..7accb59 100644
> > --- a/drivers/vfio/vfio_iommu_type1.c
> > +++ b/drivers/vfio/vfio_iommu_type1.c
> > @@ -2453,6 +2453,23 @@ static int vfio_domains_have_iommu_cache(struct
> vfio_iommu *iommu)
> >  	return ret;
> >  }
> >
> > +static int vfio_iommu_type1_check_extension(struct vfio_iommu *iommu,
> > +					    unsigned long arg)
> > +{
> > +	switch (arg) {
> > +	case VFIO_TYPE1_IOMMU:
> > +	case VFIO_TYPE1v2_IOMMU:
> > +	case VFIO_TYPE1_NESTING_IOMMU:
> > +		return 1;
> > +	case VFIO_DMA_CC_IOMMU:
> > +		if (!iommu)
> > +			return 0;
> > +		return vfio_domains_have_iommu_cache(iommu);
> > +	default:
> > +		return 0;
> > +	}
> > +}
> > +
> >  static int vfio_iommu_iova_add_cap(struct vfio_info_cap *caps,
> >  		 struct vfio_iommu_type1_info_cap_iova_range *cap_iovas,
> >  		 size_t size)
> > @@ -2529,238 +2546,255 @@ static int
> vfio_iommu_migration_build_caps(struct vfio_iommu *iommu,
> >  	return vfio_info_add_capability(caps, &cap_mig.header,
> > sizeof(cap_mig));  }
> >
> > -static long vfio_iommu_type1_ioctl(void *iommu_data,
> > -				   unsigned int cmd, unsigned long arg)
> > +static int vfio_iommu_type1_get_info(struct vfio_iommu *iommu,
> > +				     unsigned long arg)
> >  {
> > -	struct vfio_iommu *iommu = iommu_data;
> > +	struct vfio_iommu_type1_info info;
> >  	unsigned long minsz;
> > +	struct vfio_info_cap caps = { .buf = NULL, .size = 0 };
> > +	unsigned long capsz;
> > +	int ret;
> >
> > -	if (cmd == VFIO_CHECK_EXTENSION) {
> > -		switch (arg) {
> > -		case VFIO_TYPE1_IOMMU:
> > -		case VFIO_TYPE1v2_IOMMU:
> > -		case VFIO_TYPE1_NESTING_IOMMU:
> > -			return 1;
> > -		case VFIO_DMA_CC_IOMMU:
> > -			if (!iommu)
> > -				return 0;
> > -			return vfio_domains_have_iommu_cache(iommu);
> > -		default:
> > -			return 0;
> > -		}
> > -	} else if (cmd == VFIO_IOMMU_GET_INFO) {
> > -		struct vfio_iommu_type1_info info;
> > -		struct vfio_info_cap caps = { .buf = NULL, .size = 0 };
> > -		unsigned long capsz;
> > -		int ret;
> > -
> > -		minsz = offsetofend(struct vfio_iommu_type1_info,
> iova_pgsizes);
> > +	minsz = offsetofend(struct vfio_iommu_type1_info, iova_pgsizes);
> >
> > -		/* For backward compatibility, cannot require this */
> > -		capsz = offsetofend(struct vfio_iommu_type1_info, cap_offset);
> > +	/* For backward compatibility, cannot require this */
> > +	capsz = offsetofend(struct vfio_iommu_type1_info, cap_offset);
> >
> > -		if (copy_from_user(&info, (void __user *)arg, minsz))
> > -			return -EFAULT;
> > +	if (copy_from_user(&info, (void __user *)arg, minsz))
> > +		return -EFAULT;
> >
> > -		if (info.argsz < minsz)
> > -			return -EINVAL;
> > +	if (info.argsz < minsz)
> > +		return -EINVAL;
> >
> > -		if (info.argsz >= capsz) {
> > -			minsz = capsz;
> > -			info.cap_offset = 0; /* output, no-recopy necessary */
> > -		}
> > +	if (info.argsz >= capsz) {
> > +		minsz = capsz;
> > +		info.cap_offset = 0; /* output, no-recopy necessary */
> > +	}
> >
> > -		mutex_lock(&iommu->lock);
> > -		info.flags = VFIO_IOMMU_INFO_PGSIZES;
> > +	mutex_lock(&iommu->lock);
> > +	info.flags = VFIO_IOMMU_INFO_PGSIZES;
> >
> > -		info.iova_pgsizes = iommu->pgsize_bitmap;
> > +	info.iova_pgsizes = iommu->pgsize_bitmap;
> >
> > -		ret = vfio_iommu_migration_build_caps(iommu, &caps);
> > +	ret = vfio_iommu_migration_build_caps(iommu, &caps);
> >
> > -		if (!ret)
> > -			ret = vfio_iommu_iova_build_caps(iommu, &caps);
> > +	if (!ret)
> > +		ret = vfio_iommu_iova_build_caps(iommu, &caps);
> >
> > -		mutex_unlock(&iommu->lock);
> > +	mutex_unlock(&iommu->lock);
> >
> > -		if (ret)
> > -			return ret;
> > +	if (ret)
> > +		return ret;
> >
> > -		if (caps.size) {
> > -			info.flags |= VFIO_IOMMU_INFO_CAPS;
> > +	if (caps.size) {
> > +		info.flags |= VFIO_IOMMU_INFO_CAPS;
> >
> > -			if (info.argsz < sizeof(info) + caps.size) {
> > -				info.argsz = sizeof(info) + caps.size;
> > -			} else {
> > -				vfio_info_cap_shift(&caps, sizeof(info));
> > -				if (copy_to_user((void __user *)arg +
> > -						sizeof(info), caps.buf,
> > -						caps.size)) {
> > -					kfree(caps.buf);
> > -					return -EFAULT;
> > -				}
> > -				info.cap_offset = sizeof(info);
> > +		if (info.argsz < sizeof(info) + caps.size) {
> > +			info.argsz = sizeof(info) + caps.size;
> > +		} else {
> > +			vfio_info_cap_shift(&caps, sizeof(info));
> > +			if (copy_to_user((void __user *)arg +
> > +					sizeof(info), caps.buf,
> > +					caps.size)) {
> > +				kfree(caps.buf);
> > +				return -EFAULT;
> >  			}
> > -
> > -			kfree(caps.buf);
> > +			info.cap_offset = sizeof(info);
> >  		}
> >
> > -		return copy_to_user((void __user *)arg, &info, minsz) ?
> > -			-EFAULT : 0;
> > +		kfree(caps.buf);
> > +	}
> >
> > -	} else if (cmd == VFIO_IOMMU_MAP_DMA) {
> > -		struct vfio_iommu_type1_dma_map map;
> > -		uint32_t mask = VFIO_DMA_MAP_FLAG_READ |
> > -				VFIO_DMA_MAP_FLAG_WRITE;
> > +	return copy_to_user((void __user *)arg, &info, minsz) ?
> > +			-EFAULT : 0;
> > +}
> >
> > -		minsz = offsetofend(struct vfio_iommu_type1_dma_map, size);
> > +static int vfio_iommu_type1_map_dma(struct vfio_iommu *iommu,
> > +				    unsigned long arg)
> > +{
> > +	struct vfio_iommu_type1_dma_map map;
> > +	unsigned long minsz;
> > +	uint32_t mask = VFIO_DMA_MAP_FLAG_READ |
> > +			VFIO_DMA_MAP_FLAG_WRITE;
> >
> > -		if (copy_from_user(&map, (void __user *)arg, minsz))
> > -			return -EFAULT;
> > +	minsz = offsetofend(struct vfio_iommu_type1_dma_map, size);
> >
> > -		if (map.argsz < minsz || map.flags & ~mask)
> > -			return -EINVAL;
> > +	if (copy_from_user(&map, (void __user *)arg, minsz))
> > +		return -EFAULT;
> >
> > -		return vfio_dma_do_map(iommu, &map);
> > +	if (map.argsz < minsz || map.flags & ~mask)
> > +		return -EINVAL;
> >
> > -	} else if (cmd == VFIO_IOMMU_UNMAP_DMA) {
> > -		struct vfio_iommu_type1_dma_unmap unmap;
> > -		struct vfio_bitmap bitmap = { 0 };
> > -		int ret;
> > +	return vfio_dma_do_map(iommu, &map); }
> >
> > -		minsz = offsetofend(struct vfio_iommu_type1_dma_unmap,
> size);
> > +static int vfio_iommu_type1_unmap_dma(struct vfio_iommu *iommu,
> > +				      unsigned long arg)
> > +{
> > +	struct vfio_iommu_type1_dma_unmap unmap;
> > +	struct vfio_bitmap bitmap = { 0 };
> > +	unsigned long minsz;
> > +	long ret;
> >
> > -		if (copy_from_user(&unmap, (void __user *)arg, minsz))
> > -			return -EFAULT;
> > +	minsz = offsetofend(struct vfio_iommu_type1_dma_unmap, size);
> >
> > -		if (unmap.argsz < minsz ||
> > -		    unmap.flags &
> ~VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP)
> > -			return -EINVAL;
> > +	if (copy_from_user(&unmap, (void __user *)arg, minsz))
> > +		return -EFAULT;
> >
> > -		if (unmap.flags &
> VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) {
> > -			unsigned long pgshift;
> > +	if (unmap.argsz < minsz ||
> > +	    unmap.flags & ~VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP)
> > +		return -EINVAL;
> >
> > -			if (unmap.argsz < (minsz + sizeof(bitmap)))
> > -				return -EINVAL;
> > +	if (unmap.flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) {
> > +		unsigned long pgshift;
> >
> > -			if (copy_from_user(&bitmap,
> > -					   (void __user *)(arg + minsz),
> > -					   sizeof(bitmap)))
> > -				return -EFAULT;
> > +		if (unmap.argsz < (minsz + sizeof(bitmap)))
> > +			return -EINVAL;
> >
> > -			if (!access_ok((void __user *)bitmap.data, bitmap.size))
> > -				return -EINVAL;
> > +		if (copy_from_user(&bitmap,
> > +				   (void __user *)(arg + minsz),
> > +				   sizeof(bitmap)))
> > +			return -EFAULT;
> >
> > -			pgshift = __ffs(bitmap.pgsize);
> > -			ret = verify_bitmap_size(unmap.size >> pgshift,
> > -						 bitmap.size);
> > -			if (ret)
> > -				return ret;
> > -		}
> > +		if (!access_ok((void __user *)bitmap.data, bitmap.size))
> > +			return -EINVAL;
> >
> > -		ret = vfio_dma_do_unmap(iommu, &unmap, &bitmap);
> > +		pgshift = __ffs(bitmap.pgsize);
> > +		ret = verify_bitmap_size(unmap.size >> pgshift,
> > +					 bitmap.size);
> >  		if (ret)
> >  			return ret;
> > +	}
> > +
> > +	ret = vfio_dma_do_unmap(iommu, &unmap, &bitmap);
> > +	if (ret)
> > +		return ret;
> >
> > -		return copy_to_user((void __user *)arg, &unmap, minsz) ?
> > +	return copy_to_user((void __user *)arg, &unmap, minsz) ?
> >  			-EFAULT : 0;
> > -	} else if (cmd == VFIO_IOMMU_DIRTY_PAGES) {
> > -		struct vfio_iommu_type1_dirty_bitmap dirty;
> > -		uint32_t mask = VFIO_IOMMU_DIRTY_PAGES_FLAG_START |
> > -				VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP |
> > -
> 	VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP;
> > -		int ret = 0;
> > +}
> >
> > -		if (!iommu->v2)
> > -			return -EACCES;
> > +static int vfio_iommu_type1_dirty_pages(struct vfio_iommu *iommu,
> > +					unsigned long arg)
> > +{
> > +	struct vfio_iommu_type1_dirty_bitmap dirty;
> > +	uint32_t mask = VFIO_IOMMU_DIRTY_PAGES_FLAG_START |
> > +			VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP |
> > +			VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP;
> > +	unsigned long minsz;
> > +	int ret = 0;
> >
> > -		minsz = offsetofend(struct vfio_iommu_type1_dirty_bitmap,
> > -				    flags);
> > +	if (!iommu->v2)
> > +		return -EACCES;
> >
> > -		if (copy_from_user(&dirty, (void __user *)arg, minsz))
> > -			return -EFAULT;
> > +	minsz = offsetofend(struct vfio_iommu_type1_dirty_bitmap,
> > +			    flags);
> >
> > -		if (dirty.argsz < minsz || dirty.flags & ~mask)
> > -			return -EINVAL;
> > +	if (copy_from_user(&dirty, (void __user *)arg, minsz))
> > +		return -EFAULT;
> > +
> > +	if (dirty.argsz < minsz || dirty.flags & ~mask)
> > +		return -EINVAL;
> > +
> > +	/* only one flag should be set at a time */
> > +	if (__ffs(dirty.flags) != __fls(dirty.flags))
> > +		return -EINVAL;
> > +
> > +	if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_START) {
> > +		size_t pgsize;
> >
> > -		/* only one flag should be set at a time */
> > -		if (__ffs(dirty.flags) != __fls(dirty.flags))
> > +		mutex_lock(&iommu->lock);
> > +		pgsize = 1 << __ffs(iommu->pgsize_bitmap);
> > +		if (!iommu->dirty_page_tracking) {
> > +			ret = vfio_dma_bitmap_alloc_all(iommu, pgsize);
> > +			if (!ret)
> > +				iommu->dirty_page_tracking = true;
> > +		}
> > +		mutex_unlock(&iommu->lock);
> > +		return ret;
> > +	} else if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP) {
> > +		mutex_lock(&iommu->lock);
> > +		if (iommu->dirty_page_tracking) {
> > +			iommu->dirty_page_tracking = false;
> > +			vfio_dma_bitmap_free_all(iommu);
> > +		}
> > +		mutex_unlock(&iommu->lock);
> > +		return 0;
> > +	} else if (dirty.flags &
> > +			 VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP) {
> > +		struct vfio_iommu_type1_dirty_bitmap_get range;
> > +		unsigned long pgshift;
> > +		size_t data_size = dirty.argsz - minsz;
> > +		size_t iommu_pgsize;
> > +
> > +		if (!data_size || data_size < sizeof(range))
> >  			return -EINVAL;
> >
> > -		if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_START) {
> > -			size_t pgsize;
> > +		if (copy_from_user(&range, (void __user *)(arg + minsz),
> > +				   sizeof(range)))
> > +			return -EFAULT;
> >
> > -			mutex_lock(&iommu->lock);
> > -			pgsize = 1 << __ffs(iommu->pgsize_bitmap);
> > -			if (!iommu->dirty_page_tracking) {
> > -				ret = vfio_dma_bitmap_alloc_all(iommu, pgsize);
> > -				if (!ret)
> > -					iommu->dirty_page_tracking = true;
> > -			}
> > -			mutex_unlock(&iommu->lock);
> > +		if (range.iova + range.size < range.iova)
> > +			return -EINVAL;
> > +		if (!access_ok((void __user *)range.bitmap.data,
> > +			       range.bitmap.size))
> > +			return -EINVAL;
> > +
> > +		pgshift = __ffs(range.bitmap.pgsize);
> > +		ret = verify_bitmap_size(range.size >> pgshift,
> > +					 range.bitmap.size);
> > +		if (ret)
> >  			return ret;
> > -		} else if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP)
> {
> > -			mutex_lock(&iommu->lock);
> > -			if (iommu->dirty_page_tracking) {
> > -				iommu->dirty_page_tracking = false;
> > -				vfio_dma_bitmap_free_all(iommu);
> > -			}
> > -			mutex_unlock(&iommu->lock);
> > -			return 0;
> > -		} else if (dirty.flags &
> > -
> VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP) {
> > -			struct vfio_iommu_type1_dirty_bitmap_get range;
> > -			unsigned long pgshift;
> > -			size_t data_size = dirty.argsz - minsz;
> > -			size_t iommu_pgsize;
> > -
> > -			if (!data_size || data_size < sizeof(range))
> > -				return -EINVAL;
> > -
> > -			if (copy_from_user(&range, (void __user *)(arg + minsz),
> > -					   sizeof(range)))
> > -				return -EFAULT;
> >
> > -			if (range.iova + range.size < range.iova)
> > -				return -EINVAL;
> > -			if (!access_ok((void __user *)range.bitmap.data,
> > -				       range.bitmap.size))
> > -				return -EINVAL;
> > +		mutex_lock(&iommu->lock);
> >
> > -			pgshift = __ffs(range.bitmap.pgsize);
> > -			ret = verify_bitmap_size(range.size >> pgshift,
> > -						 range.bitmap.size);
> > -			if (ret)
> > -				return ret;
> > +		iommu_pgsize = (size_t)1 << __ffs(iommu->pgsize_bitmap);
> >
> > -			mutex_lock(&iommu->lock);
> > +		/* allow only smallest supported pgsize */
> > +		if (range.bitmap.pgsize != iommu_pgsize) {
> > +			ret = -EINVAL;
> > +			goto out_unlock;
> > +		}
> > +		if (range.iova & (iommu_pgsize - 1)) {
> > +			ret = -EINVAL;
> > +			goto out_unlock;
> > +		}
> > +		if (!range.size || range.size & (iommu_pgsize - 1)) {
> > +			ret = -EINVAL;
> > +			goto out_unlock;
> > +		}
> >
> > -			iommu_pgsize = (size_t)1 << __ffs(iommu-
> >pgsize_bitmap);
> > +		if (iommu->dirty_page_tracking)
> > +			ret = vfio_iova_dirty_bitmap(range.bitmap.data,
> > +					iommu, range.iova, range.size,
> > +					range.bitmap.pgsize);
> > +		else
> > +			ret = -EINVAL;
> > +out_unlock:
> > +		mutex_unlock(&iommu->lock);
> >
> > -			/* allow only smallest supported pgsize */
> > -			if (range.bitmap.pgsize != iommu_pgsize) {
> > -				ret = -EINVAL;
> > -				goto out_unlock;
> > -			}
> > -			if (range.iova & (iommu_pgsize - 1)) {
> > -				ret = -EINVAL;
> > -				goto out_unlock;
> > -			}
> > -			if (!range.size || range.size & (iommu_pgsize - 1)) {
> > -				ret = -EINVAL;
> > -				goto out_unlock;
> > -			}
> > +		return ret;
> > +	}
> >
> > -			if (iommu->dirty_page_tracking)
> > -				ret = vfio_iova_dirty_bitmap(range.bitmap.data,
> > -						iommu, range.iova, range.size,
> > -						range.bitmap.pgsize);
> > -			else
> > -				ret = -EINVAL;
> > -out_unlock:
> > -			mutex_unlock(&iommu->lock);
> > +	return -EINVAL;
> > +}
> >
> > -			return ret;
> > -		}
> > +static long vfio_iommu_type1_ioctl(void *iommu_data,
> > +				   unsigned int cmd, unsigned long arg) {
> > +	struct vfio_iommu *iommu = iommu_data;
> > +
> > +	switch (cmd) {
> > +	case VFIO_CHECK_EXTENSION:
> > +		return vfio_iommu_type1_check_extension(iommu, arg);
> > +	case VFIO_IOMMU_GET_INFO:
> > +		return vfio_iommu_type1_get_info(iommu, arg);
> > +	case VFIO_IOMMU_MAP_DMA:
> > +		return vfio_iommu_type1_map_dma(iommu, arg);
> > +	case VFIO_IOMMU_UNMAP_DMA:
> > +		return vfio_iommu_type1_unmap_dma(iommu, arg);
> > +	case VFIO_IOMMU_DIRTY_PAGES:
> > +		return vfio_iommu_type1_dirty_pages(iommu, arg);
> >  	}
> >
> >  	return -ENOTTY;