[PATCH v7 6/8] s390x/pci: let intercept devices have separate PCI groups

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

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.

Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
---
 hw/s390x/s390-pci-bus.c         | 19 ++++++++++++++--
 hw/s390x/s390-pci-vfio.c        | 40 ++++++++++++++++++++++++++++++---
 include/hw/s390x/s390-pci-bus.h |  6 ++++-
 3 files changed, 59 insertions(+), 6 deletions(-)

diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c
index e66a0dfbef..5342f7899f 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 4bf0a7e22d..985980f021 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) {
diff --git a/include/hw/s390x/s390-pci-bus.h b/include/hw/s390x/s390-pci-bus.h
index 5b09f0cf2f..0605fcea24 100644
--- a/include/hw/s390x/s390-pci-bus.h
+++ b/include/hw/s390x/s390-pci-bus.h
@@ -315,13 +315,16 @@ typedef struct ZpciFmb {
 QEMU_BUILD_BUG_MSG(offsetof(ZpciFmb, fmt0) != 48, "padding in ZpciFmb");
 
 #define ZPCI_DEFAULT_FN_GRP 0xFF
+#define ZPCI_SIM_GRP_START 0xF0
 typedef struct S390PCIGroup {
     ClpRspQueryPciGrp zpci_group;
     int id;
+    int host_id;
     QTAILQ_ENTRY(S390PCIGroup) link;
 } S390PCIGroup;
-S390PCIGroup *s390_group_create(int id);
+S390PCIGroup *s390_group_create(int id, int host_id);
 S390PCIGroup *s390_group_find(int id);
+S390PCIGroup *s390_group_find_host_sim(int host_id);
 
 struct S390PCIBusDevice {
     DeviceState qdev;
@@ -370,6 +373,7 @@ struct S390pciState {
     QTAILQ_HEAD(, S390PCIBusDevice) zpci_devs;
     QTAILQ_HEAD(, S390PCIDMACount) zpci_dma_limit;
     QTAILQ_HEAD(, S390PCIGroup) zpci_groups;
+    uint8_t next_sim_grp;
 };
 
 S390pciState *s390_get_phb(void);
-- 
2.27.0