hw/s390x/s390-pci-vfio.c

   1 /*
   2  * s390 vfio-pci interfaces
   3  *
   4  * Copyright 2020 IBM Corp.
   5  * Author(s): Matthew Rosato <mjrosato@linux.ibm.com>
   6  *
   7  * This work is licensed under the terms of the GNU GPL, version 2 or (at
   8  * your option) any later version. See the COPYING file in the top-level
   9  * directory.
  10  */
  11
  12 #include <sys/ioctl.h>
  13
  14 #include "qemu/osdep.h"
  15 #include "hw/s390x/s390-pci-bus.h"
  16 #include "hw/s390x/s390-pci-vfio.h"
  17 #include "hw/vfio/pci.h"
  18 #include "hw/vfio/vfio-common.h"
  19
  20 /*
  21  * Get the current DMA available count from vfio.  Returns true if vfio is
  22  * limiting DMA requests, false otherwise.  The current available count read
  23  * from vfio is returned in avail.
  24  */
  25 bool s390_pci_update_dma_avail(int fd, unsigned int *avail)
  26 {
  27     g_autofree struct vfio_iommu_type1_info *info;
  28     uint32_t argsz;
  29
  30     assert(avail);
  31
  32     argsz = sizeof(struct vfio_iommu_type1_info);
  33     info = g_malloc0(argsz);
  34
  35     /*
  36      * If the specified argsz is not large enough to contain all capabilities
  37      * it will be updated upon return from the ioctl.  Retry until we have
  38      * a big enough buffer to hold the entire capability chain.
  39      */
  40 retry:
  41     info->argsz = argsz;
  42
  43     if (ioctl(fd, VFIO_IOMMU_GET_INFO, info)) {
  44         return false;
  45     }
  46
  47     if (info->argsz > argsz) {
  48         argsz = info->argsz;
  49         info = g_realloc(info, argsz);
  50         goto retry;
  51     }
  52
  53     /* If the capability exists, update with the current value */
  54     return vfio_get_info_dma_avail(info, avail);
  55 }
  56
  57 S390PCIDMACount *s390_pci_start_dma_count(S390pciState *s,
  58                                           S390PCIBusDevice *pbdev)
  59 {
  60     S390PCIDMACount *cnt;
  61     uint32_t avail;
  62     VFIOPCIDevice *vpdev = container_of(pbdev->pdev, VFIOPCIDevice, pdev);
  63     int id;
  64
  65     assert(vpdev);
  66
  67     id = vpdev->vbasedev.group->container->fd;
  68
  69     if (!s390_pci_update_dma_avail(id, &avail)) {
  70         return NULL;
  71     }
  72
  73     QTAILQ_FOREACH(cnt, &s->zpci_dma_limit, link) {
  74         if (cnt->id  == id) {
  75             cnt->users++;
  76             return cnt;
  77         }
  78     }
  79
  80     cnt = g_new0(S390PCIDMACount, 1);
  81     cnt->id = id;
  82     cnt->users = 1;
  83     cnt->avail = avail;
  84     QTAILQ_INSERT_TAIL(&s->zpci_dma_limit, cnt, link);
  85     return cnt;
  86 }
  87
  88 void s390_pci_end_dma_count(S390pciState *s, S390PCIDMACount *cnt)
  89 {
  90     assert(cnt);
  91
  92     cnt->users--;
  93     if (cnt->users == 0) {
  94         QTAILQ_REMOVE(&s->zpci_dma_limit, cnt, link);
  95     }
  96 }