Re: [PATCH v2 19/19] vfio/pci: Implement huge_fault support

[kernel test robot <lkp@intel.com>]

Hi Peter,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/Peter-Xu/mm-Introduce-ARCH_SUPPORTS_HUGE_PFNMAP-and-special-bits-to-pmd-pud/20240827-044708
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20240826204353.2228736-20-peterx%40redhat.com
patch subject: [PATCH v2 19/19] vfio/pci: Implement huge_fault support
config: i386-randconfig-063-20240827 (https://download.01.org/0day-ci/archive/20240828/202408280405.b1X5dVHo-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240828/202408280405.b1X5dVHo-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202408280405.b1X5dVHo-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
   drivers/vfio/pci/vfio_pci_core.c:246:33: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/vfio/pci/vfio_pci_core.c:246:41: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/vfio/pci/vfio_pci_core.c:250:25: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/vfio/pci/vfio_pci_core.c:250:43: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/vfio/pci/vfio_pci_core.c:250:56: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/vfio/pci/vfio_pci_core.c:250:65: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/vfio/pci/vfio_pci_core.c:255:25: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/vfio/pci/vfio_pci_core.c:255:44: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/vfio/pci/vfio_pci_core.c:255:57: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/vfio/pci/vfio_pci_core.c:255:66: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/vfio/pci/vfio_pci_core.c:263:39: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/vfio/pci/vfio_pci_core.c:263:58: sparse: sparse: restricted pci_power_t degrades to integer
>> drivers/vfio/pci/vfio_pci_core.c:1705:9: sparse: sparse: cast from restricted vm_fault_t

vim +1705 drivers/vfio/pci/vfio_pci_core.c

  1660	
  1661	static vm_fault_t vfio_pci_mmap_huge_fault(struct vm_fault *vmf,
  1662						   unsigned int order)
  1663	{
  1664		struct vm_area_struct *vma = vmf->vma;
  1665		struct vfio_pci_core_device *vdev = vma->vm_private_data;
  1666		unsigned long pfn, pgoff = vmf->pgoff - vma->vm_pgoff;
  1667		vm_fault_t ret = VM_FAULT_SIGBUS;
  1668	
  1669		if (order && (vmf->address & ((PAGE_SIZE << order) - 1) ||
  1670			      vmf->address + (PAGE_SIZE << order) > vma->vm_end)) {
  1671			ret = VM_FAULT_FALLBACK;
  1672			goto out;
  1673		}
  1674	
  1675		pfn = vma_to_pfn(vma);
  1676	
  1677		down_read(&vdev->memory_lock);
  1678	
  1679		if (vdev->pm_runtime_engaged || !__vfio_pci_memory_enabled(vdev))
  1680			goto out_unlock;
  1681	
  1682		switch (order) {
  1683		case 0:
  1684			ret = vmf_insert_pfn(vma, vmf->address, pfn + pgoff);
  1685			break;
  1686	#ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP
  1687		case PMD_ORDER:
  1688			ret = vmf_insert_pfn_pmd(vmf, __pfn_to_pfn_t(pfn + pgoff,
  1689								     PFN_DEV), false);
  1690			break;
  1691	#endif
  1692	#ifdef CONFIG_ARCH_SUPPORTS_PUD_PFNMAP
  1693		case PUD_ORDER:
  1694			ret = vmf_insert_pfn_pud(vmf, __pfn_to_pfn_t(pfn + pgoff,
  1695								     PFN_DEV), false);
  1696			break;
  1697	#endif
  1698		default:
  1699			ret = VM_FAULT_FALLBACK;
  1700		}
  1701	
  1702	out_unlock:
  1703		up_read(&vdev->memory_lock);
  1704	out:
> 1705		dev_dbg_ratelimited(&vdev->pdev->dev,
  1706				   "%s(,order = %d) BAR %ld page offset 0x%lx: 0x%x\n",
  1707				    __func__, order,
  1708				    vma->vm_pgoff >>
  1709					(VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT),
  1710				    pgoff, (unsigned int)ret);
  1711	
  1712		return ret;
  1713	}
  1714	

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