s390x/pci: let intercept devices have separate PCI groups

Let's use the reserved pool of simulated PCI groups to allow intercept
devices to have separate groups from interpreted devices as some group
values may be different. If we run out of simulated PCI groups, subsequent
intercept devices just get the default group.
Furthermore, if we encounter any PCI groups from hostdevs that are marked
as simulated, let's just assign them to the default group to avoid
conflicts between host simulated groups and our own simulated groups.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Message-Id: <20220902172737.170349-7-mjrosato@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

2 files changed, 54 insertions, 5 deletions

diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c
index 2f19973913..977e7daa15 100644
--- a/hw/s390x/s390-pci-bus.c
+++ b/hw/s390x/s390-pci-bus.c
@@ -748,13 +748,14 @@ static void s390_pci_iommu_free(S390pciState *s, PCIBus *bus, int32_t devfn)
     object_unref(OBJECT(iommu));
 }
 
-S390PCIGroup *s390_group_create(int id)
+S390PCIGroup *s390_group_create(int id, int host_id)
 {
     S390PCIGroup *group;
     S390pciState *s = s390_get_phb();
 
     group = g_new0(S390PCIGroup, 1);
     group->id = id;
+    group->host_id = host_id;
     QTAILQ_INSERT_TAIL(&s->zpci_groups, group, link);
     return group;
 }
@@ -772,12 +773,25 @@ S390PCIGroup *s390_group_find(int id)
     return NULL;
 }
 
+S390PCIGroup *s390_group_find_host_sim(int host_id)
+{
+    S390PCIGroup *group;
+    S390pciState *s = s390_get_phb();
+
+    QTAILQ_FOREACH(group, &s->zpci_groups, link) {
+        if (group->id >= ZPCI_SIM_GRP_START && group->host_id == host_id) {
+            return group;
+        }
+    }
+    return NULL;
+}
+
 static void s390_pci_init_default_group(void)
 {
     S390PCIGroup *group;
     ClpRspQueryPciGrp *resgrp;
 
-    group = s390_group_create(ZPCI_DEFAULT_FN_GRP);
+    group = s390_group_create(ZPCI_DEFAULT_FN_GRP, ZPCI_DEFAULT_FN_GRP);
     resgrp = &group->zpci_group;
     resgrp->fr = 1;
     resgrp->dasm = 0;
@@ -825,6 +839,7 @@ static void s390_pcihost_realize(DeviceState *dev, Error **errp)
                                            NULL, g_free);
     s->zpci_table = g_hash_table_new_full(g_int_hash, g_int_equal, NULL, NULL);
     s->bus_no = 0;
+    s->next_sim_grp = ZPCI_SIM_GRP_START;
     QTAILQ_INIT(&s->pending_sei);
     QTAILQ_INIT(&s->zpci_devs);
     QTAILQ_INIT(&s->zpci_dma_limit);
diff --git a/hw/s390x/s390-pci-vfio.c b/hw/s390x/s390-pci-vfio.c
index 08bcc55e85..338f436e87 100644
--- a/hw/s390x/s390-pci-vfio.c
+++ b/hw/s390x/s390-pci-vfio.c
@@ -150,13 +150,18 @@ static void s390_pci_read_group(S390PCIBusDevice *pbdev,
 {
     struct vfio_info_cap_header *hdr;
     struct vfio_device_info_cap_zpci_group *cap;
+    S390pciState *s = s390_get_phb();
     ClpRspQueryPciGrp *resgrp;
     VFIOPCIDevice *vpci =  container_of(pbdev->pdev, VFIOPCIDevice, pdev);
+    uint8_t start_gid = pbdev->zpci_fn.pfgid;
 
     hdr = vfio_get_device_info_cap(info, VFIO_DEVICE_INFO_CAP_ZPCI_GROUP);
 
-    /* If capability not provided, just use the default group */
-    if (hdr == NULL) {
+    /*
+     * If capability not provided or the underlying hostdev is simulated, just
+     * use the default group.
+     */
+    if (hdr == NULL || pbdev->zpci_fn.pfgid >= ZPCI_SIM_GRP_START) {
         trace_s390_pci_clp_cap(vpci->vbasedev.name,
                                VFIO_DEVICE_INFO_CAP_ZPCI_GROUP);
         pbdev->zpci_fn.pfgid = ZPCI_DEFAULT_FN_GRP;
@@ -165,11 +170,40 @@ static void s390_pci_read_group(S390PCIBusDevice *pbdev,
     }
     cap = (void *) hdr;
 
+    /*
+     * For an intercept device, let's use an existing simulated group if one
+     * one was already created for other intercept devices in this group.
+     * If not, create a new simulated group if any are still available.
+     * If all else fails, just fall back on the default group.
+     */
+    if (!pbdev->interp) {
+        pbdev->pci_group = s390_group_find_host_sim(pbdev->zpci_fn.pfgid);
+        if (pbdev->pci_group) {
+            /* Use existing simulated group */
+            pbdev->zpci_fn.pfgid = pbdev->pci_group->id;
+            return;
+        } else {
+            if (s->next_sim_grp == ZPCI_DEFAULT_FN_GRP) {
+                /* All out of simulated groups, use default */
+                trace_s390_pci_clp_cap(vpci->vbasedev.name,
+                                       VFIO_DEVICE_INFO_CAP_ZPCI_GROUP);
+                pbdev->zpci_fn.pfgid = ZPCI_DEFAULT_FN_GRP;
+                pbdev->pci_group = s390_group_find(ZPCI_DEFAULT_FN_GRP);
+                return;
+            } else {
+                /* We can assign a new simulated group */
+                pbdev->zpci_fn.pfgid = s->next_sim_grp;
+                s->next_sim_grp++;
+                /* Fall through to create the new sim group using CLP info */
+            }
+        }
+    }
+
     /* See if the PCI group is already defined, create if not */
     pbdev->pci_group = s390_group_find(pbdev->zpci_fn.pfgid);
 
     if (!pbdev->pci_group) {
-        pbdev->pci_group = s390_group_create(pbdev->zpci_fn.pfgid);
+        pbdev->pci_group = s390_group_create(pbdev->zpci_fn.pfgid, start_gid);
 
         resgrp = &pbdev->pci_group->zpci_group;
         if (cap->flags & VFIO_DEVICE_INFO_ZPCI_FLAG_REFRESH) {