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37fa32de70
When an s390 guest is using lazy unmapping, it can result in a very large number of oustanding DMA requests, far beyond the default limit configured for vfio. Let's track DMA usage similar to vfio in the host, and trigger the guest to flush their DMA mappings before vfio runs out. Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> [aw: non-Linux build fixes] Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
96 lines
2.3 KiB
C
96 lines
2.3 KiB
C
/*
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* s390 vfio-pci interfaces
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*
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* Copyright 2020 IBM Corp.
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* Author(s): Matthew Rosato <mjrosato@linux.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or (at
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* your option) any later version. See the COPYING file in the top-level
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* directory.
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*/
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#include <sys/ioctl.h>
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#include "qemu/osdep.h"
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#include "hw/s390x/s390-pci-bus.h"
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#include "hw/s390x/s390-pci-vfio.h"
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#include "hw/vfio/pci.h"
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#include "hw/vfio/vfio-common.h"
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/*
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* Get the current DMA available count from vfio. Returns true if vfio is
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* limiting DMA requests, false otherwise. The current available count read
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* from vfio is returned in avail.
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*/
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bool s390_pci_update_dma_avail(int fd, unsigned int *avail)
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{
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g_autofree struct vfio_iommu_type1_info *info;
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uint32_t argsz;
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assert(avail);
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argsz = sizeof(struct vfio_iommu_type1_info);
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info = g_malloc0(argsz);
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/*
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* If the specified argsz is not large enough to contain all capabilities
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* it will be updated upon return from the ioctl. Retry until we have
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* a big enough buffer to hold the entire capability chain.
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*/
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retry:
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info->argsz = argsz;
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if (ioctl(fd, VFIO_IOMMU_GET_INFO, info)) {
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return false;
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}
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if (info->argsz > argsz) {
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argsz = info->argsz;
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info = g_realloc(info, argsz);
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goto retry;
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}
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/* If the capability exists, update with the current value */
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return vfio_get_info_dma_avail(info, avail);
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}
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S390PCIDMACount *s390_pci_start_dma_count(S390pciState *s,
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S390PCIBusDevice *pbdev)
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{
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S390PCIDMACount *cnt;
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uint32_t avail;
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VFIOPCIDevice *vpdev = container_of(pbdev->pdev, VFIOPCIDevice, pdev);
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int id;
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assert(vpdev);
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id = vpdev->vbasedev.group->container->fd;
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if (!s390_pci_update_dma_avail(id, &avail)) {
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return NULL;
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}
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QTAILQ_FOREACH(cnt, &s->zpci_dma_limit, link) {
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if (cnt->id == id) {
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cnt->users++;
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return cnt;
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}
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}
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cnt = g_new0(S390PCIDMACount, 1);
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cnt->id = id;
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cnt->users = 1;
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cnt->avail = avail;
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QTAILQ_INSERT_TAIL(&s->zpci_dma_limit, cnt, link);
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return cnt;
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}
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void s390_pci_end_dma_count(S390pciState *s, S390PCIDMACount *cnt)
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{
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assert(cnt);
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cnt->users--;
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if (cnt->users == 0) {
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QTAILQ_REMOVE(&s->zpci_dma_limit, cnt, link);
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}
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}
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