RE: [PATCH v6 01/15] vfio/type1: Refactor vfio_iommu_type1_ioctl()

From: Liu, Yi L
Date: Tue Jul 28 2020 - 22:27:17 EST

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> From: Alex Williamson <alex.williamson@xxxxxxxxxx>
> Sent: Tuesday, July 28, 2020 11:54 PM
>
> On Mon, 27 Jul 2020 23:27:30 -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 command 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>
> > Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
> > Suggested-by: Christoph Hellwig <hch@xxxxxxxxxxxxx>
> > Signed-off-by: Liu Yi L <yi.l.liu@xxxxxxxxx>
> > ---
>
> FYI, this commit is already in my next branch and linux-next as of today, you can
> drop it from future series. Thanks,

got it. thanks. :-)

Regards,
Yi Liu

> Alex
>
> > v4 -> v5:
> > *) address comments from Eric Auger, add r-b from Eric.
> > ---
> > drivers/vfio/vfio_iommu_type1.c | 394
> > ++++++++++++++++++++++------------------
> > 1 file changed, 213 insertions(+), 181 deletions(-)
> >
> > diff --git a/drivers/vfio/vfio_iommu_type1.c
> > b/drivers/vfio/vfio_iommu_type1.c index 5e556ac..3bd70ff 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)
> > @@ -2529,241 +2546,256 @@ 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;
> > + int 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;
> >
> > - /* only one flag should be set at a time */
> > - if (__ffs(dirty.flags) != __fls(dirty.flags))
> > - return -EINVAL;
> > + if (dirty.argsz < minsz || dirty.flags & ~mask)
> > + 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))
> > + return -EINVAL;
> >
> > - 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 (copy_from_user(&range, (void __user *)(arg + minsz),
> > - sizeof(range)))
> > - return -EFAULT;
> > + if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_START) {
> > + size_t pgsize;
> >
> > - 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);
> > + 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;
> >
> > - pgshift = __ffs(range.bitmap.pgsize);
> > - ret = verify_bitmap_size(range.size >> pgshift,
> > - range.bitmap.size);
> > - if (ret)
> > - return ret;
> > + if (!data_size || data_size < sizeof(range))
> > + return -EINVAL;
> >
> > - mutex_lock(&iommu->lock);
> > + if (copy_from_user(&range, (void __user *)(arg + minsz),
> > + sizeof(range)))
> > + return -EFAULT;
> >
> > - iommu_pgsize = (size_t)1 << __ffs(iommu->pgsize_bitmap);
> > + if (range.iova + range.size < range.iova)
> > + return -EINVAL;
> > + if (!access_ok((void __user *)range.bitmap.data,
> > + range.bitmap.size))
> > + return -EINVAL;
> >
> > - /* 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;
> > - }
> > + pgshift = __ffs(range.bitmap.pgsize);
> > + ret = verify_bitmap_size(range.size >> pgshift,
> > + range.bitmap.size);
> > + if (ret)
> > + 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);
> > + mutex_lock(&iommu->lock);
> >
> > - return ret;
> > + iommu_pgsize = (size_t)1 << __ffs(iommu->pgsize_bitmap);
> > +
> > + /* 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;
> > }
> > +
> > + 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 ret;
> > }
> >
> > - return -ENOTTY;
> > + return -EINVAL;
> > +}
> > +
> > +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);
> > + default:
> > + return -ENOTTY;
> > + }
> > }
> >
> > static int vfio_iommu_type1_register_notifier(void *iommu_data,

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