[Qemu-devel] [PATCH v3 5/5] s390: vfio_pci: Get zPCI function info from host

[Matthew Rosato <mjrosato@linux.ibm.com>]

From: Pierre Morel <pmorel@linux.ibm.com>

We use the VFIO_REGION_SUBTYPE_ZDEV_CLP subregion of
PCI_VENDOR_ID_IBM to retrieve the CLP information the
kernel exports.

To be compatible with previous kernel versions we fall back
on previous predefined values, same as the emulation values,
when the region is not found or when any problem happens
during the search for the information.

Once we retrieved the host device information, we take care to
- use the virtual UID and FID
- Disable all the IOMMU flags we do not support yet.
  Just keeping the refresh bit.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
---
 hw/s390x/s390-pci-bus.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++--
 hw/s390x/s390-pci-bus.h |  2 ++
 2 files changed, 83 insertions(+), 2 deletions(-)

diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c
index 0d404c3..5069795 100644
--- a/hw/s390x/s390-pci-bus.c
+++ b/hw/s390x/s390-pci-bus.c
@@ -15,6 +15,8 @@
 #include "qapi/error.h"
 #include "qapi/visitor.h"
 #include "cpu.h"
+#include "s390-pci-clp.h"
+#include <linux/vfio_zdev.h>
 #include "s390-pci-bus.h"
 #include "s390-pci-inst.h"
 #include "hw/pci/pci_bus.h"
@@ -24,6 +26,9 @@
 #include "qemu/error-report.h"
 #include "qemu/module.h"
 
+#include "hw/vfio/pci.h"
+#include <sys/ioctl.h>
+
 #ifndef DEBUG_S390PCI_BUS
 #define DEBUG_S390PCI_BUS  0
 #endif
@@ -781,6 +786,76 @@ static void set_pbdev_info(S390PCIBusDevice *pbdev)
     pbdev->pci_grp = s390_grp_find(ZPCI_DEFAULT_FN_GRP);
 }
 
+static int get_pbdev_info(S390PCIBusDevice *pbdev)
+{
+    VFIOPCIDevice *vfio_pci;
+    VFIODevice *vdev;
+    struct vfio_region_info *info;
+    CLPRegion *clp_region;
+    int size;
+    int ret;
+
+    vfio_pci = container_of(pbdev->pdev, VFIOPCIDevice, pdev);
+    vdev = &vfio_pci->vbasedev;
+
+    if (vdev->num_regions < VFIO_PCI_NUM_REGIONS + 1) {
+        /* Fall back to old handling */
+        return -ENODEV;
+    }
+
+    ret = vfio_get_dev_region_info(vdev,
+                                   PCI_VENDOR_ID_IBM |
+                                   VFIO_REGION_TYPE_PCI_VENDOR_TYPE,
+                                   VFIO_REGION_SUBTYPE_ZDEV_CLP, &info);
+    if (ret) {
+        /* Fall back to old handling */
+        return -EIO;
+    }
+
+    if (info->size != (sizeof(CLPRegion) + CLP_UTIL_STR_LEN)) {
+        /* Fall back to old handling */
+        g_free(info);
+        return -ENOMEM;
+    }
+    clp_region = g_malloc0(sizeof(*clp_region) + CLP_UTIL_STR_LEN);
+    size = pread(vdev->fd, clp_region, (sizeof(*clp_region) + CLP_UTIL_STR_LEN),
+                 info->offset);
+    if (size != (sizeof(*clp_region) + CLP_UTIL_STR_LEN)) {
+        goto end;
+    }
+
+    pbdev->zpci_fn.fid = pbdev->fid;
+    pbdev->zpci_fn.uid = pbdev->uid;
+    pbdev->zpci_fn.sdma = clp_region->start_dma;
+    pbdev->zpci_fn.edma = clp_region->end_dma;
+    pbdev->zpci_fn.pchid = clp_region->pchid;
+    pbdev->zpci_fn.ug = clp_region->gid;
+    pbdev->pci_grp = s390_grp_find(clp_region->gid);
+
+    if (!pbdev->pci_grp) {
+        ClpRspQueryPciGrp *resgrp;
+
+        pbdev->pci_grp = s390_grp_create(clp_region->gid);
+
+        resgrp = &pbdev->pci_grp->zpci_grp;
+        if (clp_region->flags & VFIO_PCI_ZDEV_FLAGS_REFRESH) {
+            resgrp->fr = 1;
+        }
+        stq_p(&resgrp->dasm, clp_region->dasm);
+        stq_p(&resgrp->msia, clp_region->msi_addr);
+        stw_p(&resgrp->mui, clp_region->mui);
+        stw_p(&resgrp->i, clp_region->noi);
+        /* These two must be queried in a next iteration */
+        stw_p(&resgrp->maxstbl, 128);
+        resgrp->version = 0;
+    }
+
+end:
+    g_free(info);
+    g_free(clp_region);
+    return ret;
+}
+
 static void s390_pcihost_realize(DeviceState *dev, Error **errp)
 {
     PCIBus *b;
@@ -853,7 +928,8 @@ static int s390_pci_msix_init(S390PCIBusDevice *pbdev)
     name = g_strdup_printf("msix-s390-%04x", pbdev->uid);
     memory_region_init_io(&pbdev->msix_notify_mr, OBJECT(pbdev),
                           &s390_msi_ctrl_ops, pbdev, name, PAGE_SIZE);
-    memory_region_add_subregion(&pbdev->iommu->mr, ZPCI_MSI_ADDR,
+    memory_region_add_subregion(&pbdev->iommu->mr,
+                                pbdev->pci_grp->zpci_grp.msia,
                                 &pbdev->msix_notify_mr);
     g_free(name);
 
@@ -1003,12 +1079,15 @@ static void s390_pcihost_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
         pbdev->iommu = s390_pci_get_iommu(s, pci_get_bus(pdev), pdev->devfn);
         pbdev->iommu->pbdev = pbdev;
         pbdev->state = ZPCI_FS_DISABLED;
-        set_pbdev_info(pbdev);
 
         if (object_dynamic_cast(OBJECT(dev), "vfio-pci")) {
             pbdev->fh |= FH_SHM_VFIO;
+            if (get_pbdev_info(pbdev) != 0) {
+                set_pbdev_info(pbdev);
+            }
         } else {
             pbdev->fh |= FH_SHM_EMUL;
+            set_pbdev_info(pbdev);
         }
 
         if (s390_pci_msix_init(pbdev)) {
diff --git a/hw/s390x/s390-pci-bus.h b/hw/s390x/s390-pci-bus.h
index 8c969d1..151e2d0 100644
--- a/hw/s390x/s390-pci-bus.h
+++ b/hw/s390x/s390-pci-bus.h
@@ -320,6 +320,8 @@ typedef struct S390PCIGroup {
 } S390PCIGroup;
 S390PCIGroup *s390_grp_find(int ug);
 
+typedef struct vfio_region_zpci_info CLPRegion;
+
 struct S390PCIBusDevice {
     DeviceState qdev;
     PCIDevice *pdev;
-- 
1.8.3.1