qemu

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/*
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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 "qemu/osdep.h"
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#include <sys/ioctl.h>
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#include <linux/vfio.h>
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#include <linux/vfio_zdev.h>
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#include "trace.h"
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#include "hw/s390x/s390-pci-bus.h"
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#include "hw/s390x/s390-pci-clp.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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    uint32_t argsz = sizeof(struct vfio_iommu_type1_info);
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    g_autofree struct vfio_iommu_type1_info *info = g_malloc0(argsz);
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    assert(avail);
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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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    if (!vpdev->vbasedev.group) {
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        return NULL;
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    }
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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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    pbdev->iommu->max_dma_limit = avail;
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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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static void s390_pci_read_base(S390PCIBusDevice *pbdev,
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                               struct vfio_device_info *info)
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{
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    struct vfio_info_cap_header *hdr;
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    struct vfio_device_info_cap_zpci_base *cap;
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    VFIOPCIDevice *vpci =  container_of(pbdev->pdev, VFIOPCIDevice, pdev);
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    uint64_t vfio_size;
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    hdr = vfio_get_device_info_cap(info, VFIO_DEVICE_INFO_CAP_ZPCI_BASE);
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    /* If capability not provided, just leave the defaults in place */
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    if (hdr == NULL) {
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        trace_s390_pci_clp_cap(vpci->vbasedev.name,
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                               VFIO_DEVICE_INFO_CAP_ZPCI_BASE);
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        return;
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    }
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    cap = (void *) hdr;
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    pbdev->zpci_fn.sdma = cap->start_dma;
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    pbdev->zpci_fn.edma = cap->end_dma;
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    pbdev->zpci_fn.pchid = cap->pchid;
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    pbdev->zpci_fn.vfn = cap->vfn;
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    pbdev->zpci_fn.pfgid = cap->gid;
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    /* The following values remain 0 until we support other FMB formats */
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    pbdev->zpci_fn.fmbl = 0;
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    pbdev->zpci_fn.pft = 0;
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    /* Store function type separately for type-specific behavior */
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    pbdev->pft = cap->pft;
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    /*
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     * If appropriate, reduce the size of the supported DMA aperture reported
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     * to the guest based upon the vfio DMA limit.
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     */
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    vfio_size = pbdev->iommu->max_dma_limit << TARGET_PAGE_BITS;
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    if (vfio_size > 0 && vfio_size < cap->end_dma - cap->start_dma + 1) {
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        pbdev->zpci_fn.edma = cap->start_dma + vfio_size - 1;
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    }
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}
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static bool get_host_fh(S390PCIBusDevice *pbdev, struct vfio_device_info *info,
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                        uint32_t *fh)
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{
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    struct vfio_info_cap_header *hdr;
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    struct vfio_device_info_cap_zpci_base *cap;
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    VFIOPCIDevice *vpci = container_of(pbdev->pdev, VFIOPCIDevice, pdev);
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    hdr = vfio_get_device_info_cap(info, VFIO_DEVICE_INFO_CAP_ZPCI_BASE);
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    /* Can only get the host fh with version 2 or greater */
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    if (hdr == NULL || hdr->version < 2) {
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        trace_s390_pci_clp_cap(vpci->vbasedev.name,
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                               VFIO_DEVICE_INFO_CAP_ZPCI_BASE);
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        return false;
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    }
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    cap = (void *) hdr;
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    *fh = cap->fh;
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    return true;
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}
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static void s390_pci_read_group(S390PCIBusDevice *pbdev,
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                                struct vfio_device_info *info)
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{
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    struct vfio_info_cap_header *hdr;
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    struct vfio_device_info_cap_zpci_group *cap;
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    S390pciState *s = s390_get_phb();
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    ClpRspQueryPciGrp *resgrp;
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    VFIOPCIDevice *vpci =  container_of(pbdev->pdev, VFIOPCIDevice, pdev);
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    uint8_t start_gid = pbdev->zpci_fn.pfgid;
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    hdr = vfio_get_device_info_cap(info, VFIO_DEVICE_INFO_CAP_ZPCI_GROUP);
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    /*
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     * If capability not provided or the underlying hostdev is simulated, just
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     * use the default group.
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     */
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    if (hdr == NULL || pbdev->zpci_fn.pfgid >= ZPCI_SIM_GRP_START) {
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        trace_s390_pci_clp_cap(vpci->vbasedev.name,
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                               VFIO_DEVICE_INFO_CAP_ZPCI_GROUP);
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        pbdev->zpci_fn.pfgid = ZPCI_DEFAULT_FN_GRP;
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        pbdev->pci_group = s390_group_find(ZPCI_DEFAULT_FN_GRP);
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        return;
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    }
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    cap = (void *) hdr;
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    /*
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     * For an intercept device, let's use an existing simulated group if one
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     * one was already created for other intercept devices in this group.
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     * If not, create a new simulated group if any are still available.
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     * If all else fails, just fall back on the default group.
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     */
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    if (!pbdev->interp) {
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        pbdev->pci_group = s390_group_find_host_sim(pbdev->zpci_fn.pfgid);
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        if (pbdev->pci_group) {
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            /* Use existing simulated group */
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            pbdev->zpci_fn.pfgid = pbdev->pci_group->id;
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            return;
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        } else {
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            if (s->next_sim_grp == ZPCI_DEFAULT_FN_GRP) {
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                /* All out of simulated groups, use default */
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                trace_s390_pci_clp_cap(vpci->vbasedev.name,
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                                       VFIO_DEVICE_INFO_CAP_ZPCI_GROUP);
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                pbdev->zpci_fn.pfgid = ZPCI_DEFAULT_FN_GRP;
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                pbdev->pci_group = s390_group_find(ZPCI_DEFAULT_FN_GRP);
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                return;
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            } else {
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                /* We can assign a new simulated group */
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                pbdev->zpci_fn.pfgid = s->next_sim_grp;
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                s->next_sim_grp++;
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                /* Fall through to create the new sim group using CLP info */
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            }
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        }
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    }
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    /* See if the PCI group is already defined, create if not */
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    pbdev->pci_group = s390_group_find(pbdev->zpci_fn.pfgid);
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    if (!pbdev->pci_group) {
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        pbdev->pci_group = s390_group_create(pbdev->zpci_fn.pfgid, start_gid);
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        resgrp = &pbdev->pci_group->zpci_group;
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        if (cap->flags & VFIO_DEVICE_INFO_ZPCI_FLAG_REFRESH) {
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            resgrp->fr = 1;
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        }
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        resgrp->dasm = cap->dasm;
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        resgrp->msia = cap->msi_addr;
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        resgrp->mui = cap->mui;
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        resgrp->i = cap->noi;
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        if (pbdev->interp && hdr->version >= 2) {
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            resgrp->maxstbl = cap->imaxstbl;
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        } else {
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            resgrp->maxstbl = cap->maxstbl;
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        }
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        resgrp->version = cap->version;
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        resgrp->dtsm = ZPCI_DTSM;
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    }
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}
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static void s390_pci_read_util(S390PCIBusDevice *pbdev,
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                               struct vfio_device_info *info)
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{
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    struct vfio_info_cap_header *hdr;
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    struct vfio_device_info_cap_zpci_util *cap;
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    VFIOPCIDevice *vpci =  container_of(pbdev->pdev, VFIOPCIDevice, pdev);
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    hdr = vfio_get_device_info_cap(info, VFIO_DEVICE_INFO_CAP_ZPCI_UTIL);
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    /* If capability not provided, just leave the defaults in place */
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    if (hdr == NULL) {
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        trace_s390_pci_clp_cap(vpci->vbasedev.name,
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                               VFIO_DEVICE_INFO_CAP_ZPCI_UTIL);
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        return;
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    }
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    cap = (void *) hdr;
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    if (cap->size > CLP_UTIL_STR_LEN) {
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        trace_s390_pci_clp_cap_size(vpci->vbasedev.name, cap->size,
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                                    VFIO_DEVICE_INFO_CAP_ZPCI_UTIL);
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        return;
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    }
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    pbdev->zpci_fn.flags |= CLP_RSP_QPCI_MASK_UTIL;
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    memcpy(pbdev->zpci_fn.util_str, cap->util_str, CLP_UTIL_STR_LEN);
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}
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static void s390_pci_read_pfip(S390PCIBusDevice *pbdev,
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                               struct vfio_device_info *info)
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{
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    struct vfio_info_cap_header *hdr;
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    struct vfio_device_info_cap_zpci_pfip *cap;
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    VFIOPCIDevice *vpci =  container_of(pbdev->pdev, VFIOPCIDevice, pdev);
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    hdr = vfio_get_device_info_cap(info, VFIO_DEVICE_INFO_CAP_ZPCI_PFIP);
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    /* If capability not provided, just leave the defaults in place */
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    if (hdr == NULL) {
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        trace_s390_pci_clp_cap(vpci->vbasedev.name,
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                               VFIO_DEVICE_INFO_CAP_ZPCI_PFIP);
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        return;
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    }
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    cap = (void *) hdr;
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    if (cap->size > CLP_PFIP_NR_SEGMENTS) {
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        trace_s390_pci_clp_cap_size(vpci->vbasedev.name, cap->size,
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                                    VFIO_DEVICE_INFO_CAP_ZPCI_PFIP);
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        return;
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    }
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    memcpy(pbdev->zpci_fn.pfip, cap->pfip, CLP_PFIP_NR_SEGMENTS);
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}
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static struct vfio_device_info *get_device_info(S390PCIBusDevice *pbdev)
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{
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    VFIOPCIDevice *vfio_pci = container_of(pbdev->pdev, VFIOPCIDevice, pdev);
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    return vfio_get_device_info(vfio_pci->vbasedev.fd);
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}
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/*
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 * Get the host function handle from the vfio CLP capabilities chain.  Returns
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 * true if a fh value was placed into the provided buffer.  Returns false
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 * if a fh could not be obtained (ioctl failed or capability version does
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 * not include the fh)
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 */
309
bool s390_pci_get_host_fh(S390PCIBusDevice *pbdev, uint32_t *fh)
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{
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    g_autofree struct vfio_device_info *info = NULL;
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    assert(fh);
314

315
    info = get_device_info(pbdev);
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    if (!info) {
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        return false;
318
    }
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    return get_host_fh(pbdev, info, fh);
321
}
322

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/*
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 * This function will issue the VFIO_DEVICE_GET_INFO ioctl and look for
325
 * capabilities that contain information about CLP features provided by the
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 * underlying host.
327
 * On entry, defaults have already been placed into the guest CLP response
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 * buffers.  On exit, defaults will have been overwritten for any CLP features
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 * found in the capability chain; defaults will remain for any CLP features not
330
 * found in the chain.
331
 */
332
void s390_pci_get_clp_info(S390PCIBusDevice *pbdev)
333
{
334
    g_autofree struct vfio_device_info *info = NULL;
335

336
    info = get_device_info(pbdev);
337
    if (!info) {
338
        return;
339
    }
340

341
    /*
342
     * Find the CLP features provided and fill in the guest CLP responses.
343
     * Always call s390_pci_read_base first as information from this could
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     * determine which function group is used in s390_pci_read_group.
345
     * For any feature not found, the default values will remain in the CLP
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     * response.
347
     */
348
    s390_pci_read_base(pbdev, info);
349
    s390_pci_read_group(pbdev, info);
350
    s390_pci_read_util(pbdev, info);
351
    s390_pci_read_pfip(pbdev, info);
352

353
    return;
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}
355