From e8f90717ed3b58e81c480b3aa38e641c0da5a456 Mon Sep 17 00:00:00 2001 From: Nicolin Chen Date: Fri, 22 Jul 2022 19:02:47 -0700 Subject: [PATCH] vfio: Make vfio_unpin_pages() return void There's only one caller that checks its return value with a WARN_ON_ONCE, while all other callers don't check the return value at all. Above that, an undo function should not fail. So, simplify the API to return void by embedding similar WARN_ONs. Also for users to pinpoint which condition fails, separate WARN_ON lines, yet remove the "driver->ops->unpin_pages" check, since it's unreasonable for callers to unpin on something totally random that wasn't even pinned. And remove NULL pointer checks for they would trigger oops vs. warnings. Note that npage is already validated in the vfio core, thus drop the same check in the type1 code. Suggested-by: Christoph Hellwig Reviewed-by: Christoph Hellwig Reviewed-by: Jason Gunthorpe Reviewed-by: Kirti Wankhede Tested-by: Terrence Xu Signed-off-by: Nicolin Chen Link: https://lore.kernel.org/r/20220723020256.30081-2-nicolinc@nvidia.com Signed-off-by: Alex Williamson --- .../driver-api/vfio-mediated-device.rst | 2 +- drivers/gpu/drm/i915/gvt/kvmgt.c | 5 +---- drivers/vfio/vfio.c | 21 +++++++------------ drivers/vfio/vfio.h | 2 +- drivers/vfio/vfio_iommu_type1.c | 15 ++++++------- include/linux/vfio.h | 4 ++-- 6 files changed, 18 insertions(+), 31 deletions(-) diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst index 1c57815619fdf..b0fdf76b339a4 100644 --- a/Documentation/driver-api/vfio-mediated-device.rst +++ b/Documentation/driver-api/vfio-mediated-device.rst @@ -265,7 +265,7 @@ driver:: int vfio_pin_pages(struct vfio_device *device, unsigned long *user_pfn, int npage, int prot, unsigned long *phys_pfn); - int vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn, + void vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn, int npage); These functions call back into the back-end IOMMU module by using the pin_pages diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index ecd5bb37b63a2..4d32a27489588 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -231,18 +231,15 @@ static void intel_gvt_cleanup_vgpu_type_groups(struct intel_gvt *gvt) static void gvt_unpin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn, unsigned long size) { - struct drm_i915_private *i915 = vgpu->gvt->gt->i915; int total_pages; int npage; - int ret; total_pages = roundup(size, PAGE_SIZE) / PAGE_SIZE; for (npage = 0; npage < total_pages; npage++) { unsigned long cur_gfn = gfn + npage; - ret = vfio_unpin_pages(&vgpu->vfio_device, &cur_gfn, 1); - drm_WARN_ON(&i915->drm, ret != 1); + vfio_unpin_pages(&vgpu->vfio_device, &cur_gfn, 1); } } diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index b3ce8073cfb1f..92b10aafae28b 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -1983,31 +1983,24 @@ EXPORT_SYMBOL(vfio_pin_pages); * PFNs should not be greater than VFIO_PIN_PAGES_MAX_ENTRIES. * @npage [in] : count of elements in user_pfn array. This count should not * be greater than VFIO_PIN_PAGES_MAX_ENTRIES. - * Return error or number of pages unpinned. */ -int vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn, - int npage) +void vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn, + int npage) { struct vfio_container *container; struct vfio_iommu_driver *driver; - int ret; - if (!user_pfn || !npage || !vfio_assert_device_open(device)) - return -EINVAL; + if (WARN_ON(npage <= 0 || npage > VFIO_PIN_PAGES_MAX_ENTRIES)) + return; - if (npage > VFIO_PIN_PAGES_MAX_ENTRIES) - return -E2BIG; + if (WARN_ON(!vfio_assert_device_open(device))) + return; /* group->container cannot change while a vfio device is open */ container = device->group->container; driver = container->iommu_driver; - if (likely(driver && driver->ops->unpin_pages)) - ret = driver->ops->unpin_pages(container->iommu_data, user_pfn, - npage); - else - ret = -ENOTTY; - return ret; + driver->ops->unpin_pages(container->iommu_data, user_pfn, npage); } EXPORT_SYMBOL(vfio_unpin_pages); diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h index 4a7db1f3c33e7..6a8424b407c7e 100644 --- a/drivers/vfio/vfio.h +++ b/drivers/vfio/vfio.h @@ -53,7 +53,7 @@ struct vfio_iommu_driver_ops { unsigned long *user_pfn, int npage, int prot, unsigned long *phys_pfn); - int (*unpin_pages)(void *iommu_data, + void (*unpin_pages)(void *iommu_data, unsigned long *user_pfn, int npage); void (*register_device)(void *iommu_data, struct vfio_device *vdev); diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 026a1d2553a26..e49fbe9968efe 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -949,20 +949,16 @@ pin_done: return ret; } -static int vfio_iommu_type1_unpin_pages(void *iommu_data, - unsigned long *user_pfn, - int npage) +static void vfio_iommu_type1_unpin_pages(void *iommu_data, + unsigned long *user_pfn, int npage) { struct vfio_iommu *iommu = iommu_data; bool do_accounting; int i; - if (!iommu || !user_pfn || npage <= 0) - return -EINVAL; - /* Supported for v2 version only */ - if (!iommu->v2) - return -EACCES; + if (WARN_ON(!iommu->v2)) + return; mutex_lock(&iommu->lock); @@ -980,7 +976,8 @@ static int vfio_iommu_type1_unpin_pages(void *iommu_data, } mutex_unlock(&iommu->lock); - return i > 0 ? i : -EINVAL; + + WARN_ON(i != npage); } static long vfio_sync_unpin(struct vfio_dma *dma, struct vfio_domain *domain, diff --git a/include/linux/vfio.h b/include/linux/vfio.h index 19cefbaa3d06a..9f7d74c24925a 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -163,8 +163,8 @@ bool vfio_file_has_dev(struct file *file, struct vfio_device *device); int vfio_pin_pages(struct vfio_device *device, unsigned long *user_pfn, int npage, int prot, unsigned long *phys_pfn); -int vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn, - int npage); +void vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn, + int npage); int vfio_dma_rw(struct vfio_device *device, dma_addr_t user_iova, void *data, size_t len, bool write); -- 2.30.2