Re: [Qemu-devel] [PATCH 3/3] vfio/pci: Add ioeventfd support

[kbuild test robot]

Hi Alex,

I love your patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v4.16-rc4 next-20180306]
[if your patch is applied to the wrong git tree, please drop us a note to help 
improve the system]

url:    
https://github.com/0day-ci/linux/commits/Alex-Williamson/vfio-pci-Pull-BAR-mapping-setup-from-read-write-path/20180303-015851
reproduce:
        # apt-get install sparse
        make ARCH=x86_64 allmodconfig
        make C=1 CF=-D__CHECK_ENDIAN__


sparse warnings: (new ones prefixed by >>)

>> drivers/vfio/pci/vfio_pci_rdwr.c:290:1: sparse: incorrect type in argument 2 
>> (different address spaces) @@    expected void [noderef] <asn:2>*<noident> 
>> @@    got sn:2>*<noident> @@
   drivers/vfio/pci/vfio_pci_rdwr.c:290:1:    expected void [noderef] 
<asn:2>*<noident>
   drivers/vfio/pci/vfio_pci_rdwr.c:290:1:    got void *opaque
   drivers/vfio/pci/vfio_pci_rdwr.c:291:1: sparse: incorrect type in argument 2 
(different address spaces) @@    expected void [noderef] <asn:2>*<noident> @@   
 got sn:2>*<noident> @@
   drivers/vfio/pci/vfio_pci_rdwr.c:291:1:    expected void [noderef] 
<asn:2>*<noident>
   drivers/vfio/pci/vfio_pci_rdwr.c:291:1:    got void *opaque
   drivers/vfio/pci/vfio_pci_rdwr.c:292:1: sparse: incorrect type in argument 2 
(different address spaces) @@    expected void [noderef] <asn:2>*<noident> @@   
 got sn:2>*<noident> @@
   drivers/vfio/pci/vfio_pci_rdwr.c:292:1:    expected void [noderef] 
<asn:2>*<noident>
   drivers/vfio/pci/vfio_pci_rdwr.c:292:1:    got void *opaque
>> drivers/vfio/pci/vfio_pci_rdwr.c:378:52: sparse: incorrect type in argument 
>> 1 (different address spaces) @@    expected void *opaque @@    got void 
>> [noderef] <avoid *opaque @@
   drivers/vfio/pci/vfio_pci_rdwr.c:378:52:    expected void *opaque
   drivers/vfio/pci/vfio_pci_rdwr.c:378:52:    got void [noderef] <asn:2>*

vim +290 drivers/vfio/pci/vfio_pci_rdwr.c

   286  
   287  #ifdef iowrite64
   288  VFIO_PCI_IOEVENTFD_HANDLER(64)
   289  #endif
 > 290  VFIO_PCI_IOEVENTFD_HANDLER(32)
   291  VFIO_PCI_IOEVENTFD_HANDLER(16)
   292  VFIO_PCI_IOEVENTFD_HANDLER(8)
   293  
   294  long vfio_pci_ioeventfd(struct vfio_pci_device *vdev, loff_t offset,
   295                          uint64_t data, int count, int fd)
   296  {
   297          struct pci_dev *pdev = vdev->pdev;
   298          loff_t pos = offset & VFIO_PCI_OFFSET_MASK;
   299          int ret, bar = VFIO_PCI_OFFSET_TO_INDEX(offset);
   300          struct vfio_pci_ioeventfd *ioeventfd;
   301          int (*handler)(void *addr, void *value);
   302  
   303          /* Only support ioeventfds into BARs */
   304          if (bar > VFIO_PCI_BAR5_REGION_INDEX)
   305                  return -EINVAL;
   306  
   307          if (pos + count > pci_resource_len(pdev, bar))
   308                  return -EINVAL;
   309  
   310          /* Disallow ioeventfds working around MSI-X table writes */
   311          if (bar == vdev->msix_bar &&
   312              !(pos + count <= vdev->msix_offset ||
   313                pos >= vdev->msix_offset + vdev->msix_size))
   314                  return -EINVAL;
   315  
   316          switch (count) {
   317          case 1:
   318                  handler = &vfio_pci_ioeventfd_handler8;
   319                  break;
   320          case 2:
   321                  handler = &vfio_pci_ioeventfd_handler16;
   322                  break;
   323          case 4:
   324                  handler = &vfio_pci_ioeventfd_handler32;
   325                  break;
   326  #ifdef iowrite64
   327          case 8:
   328                  handler = &vfio_pci_ioeventfd_handler64;
   329                  break;
   330  #endif
   331          default:
   332                  return -EINVAL;
   333          }
   334  
   335          ret = vfio_pci_setup_barmap(vdev, bar);
   336          if (ret)
   337                  return ret;
   338  
   339          mutex_lock(&vdev->ioeventfds_lock);
   340  
   341          list_for_each_entry(ioeventfd, &vdev->ioeventfds_list, next) {
   342                  if (ioeventfd->pos == pos && ioeventfd->bar == bar &&
   343                      ioeventfd->data == data && ioeventfd->count == 
count) {
   344                          if (fd == -1) {
   345                                  vfio_virqfd_disable(&ioeventfd->virqfd);
   346                                  list_del(&ioeventfd->next);
   347                                  vdev->ioeventfds_nr--;
   348                                  kfree(ioeventfd);
   349                                  ret = 0;
   350                          } else
   351                                  ret = -EEXIST;
   352  
   353                          goto out_unlock;
   354                  }
   355          }
   356  
   357          if (fd < 0) {
   358                  ret = -ENODEV;
   359                  goto out_unlock;
   360          }
   361  
   362          if (vdev->ioeventfds_nr >= VFIO_PCI_IOEVENTFD_MAX) {
   363                  ret = -ENOSPC;
   364                  goto out_unlock;
   365          }
   366  
   367          ioeventfd = kzalloc(sizeof(*ioeventfd), GFP_KERNEL);
   368          if (!ioeventfd) {
   369                  ret = -ENOMEM;
   370                  goto out_unlock;
   371          }
   372  
   373          ioeventfd->pos = pos;
   374          ioeventfd->bar = bar;
   375          ioeventfd->data = data;
   376          ioeventfd->count = count;
   377  
 > 378          ret = vfio_virqfd_enable(vdev->barmap[bar] + pos, handler, NULL,

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