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 } 97