[Qemu-devel] [PATCH qemu v2 2/2] spapr_pci: Remove constraints about VFIO-PCI devices

[Alexey Kardashevskiy <aik@ozlabs.ru>]

So far there were 2 limitations enforced on an emulated PHB
regarding VFIO:
1) only one IOMMU group per IOMMU container was allowed and
the spapr-pci-vfio-host-bridge device has an IOMMU ID property for this;
2) only one IOMMU container per PHB was allowed as a group
can only be attached to one container.

However these are not really necessary so we are removing them here.

This deprecates IOMMU group ID and changes vfio_container_do_ioctl()
not to receive it. Instead of getting a container from a group ID,
this calls ioctl() for every container attached to the PHB address space.
This allows multiple containers on the same PHB which means multiple
groups per PHB. Note that this will lead to every H_PUT_TCE&etc call
to be passed to every container separately which will affect
the performance. For 32bit devices it is still recommended to put
every group to a separate PHB.

Since the existing VFIO code is already trying to share a container for
multiple groups, just removing a group id from
the vfio_container_do_ioctl() allows the existing code to share
a container if it is supported by the host kernel.

This replaces the check for a group id to be set correctly with
the check that it is not set.

This removes casts to sPAPRPHBVFIOState as none of sPAPRPHBVFIOState
members is accessed here.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 hw/ppc/spapr_pci.c      | 10 +++++-----
 hw/ppc/spapr_pci_vfio.c | 17 ++++++-----------
 hw/vfio/common.c        | 22 ++++++----------------
 include/hw/vfio/vfio.h  |  3 +--
 4 files changed, 18 insertions(+), 34 deletions(-)

diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index 4e289cb..1b7559d 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -810,11 +810,6 @@ static int spapr_phb_dma_capabilities_update(sPAPRPHBState *sphb)
     pci_for_each_device(bus, pci_bus_num(bus), spapr_phb_walk_devices, sphb);
 
     if (sphb->vfio_num) {
-        if (sphb->iommugroupid == -1) {
-            error_report("Wrong IOMMU group ID %d", sphb->iommugroupid);
-            return -1;
-        }
-
         ret = spapr_phb_vfio_dma_capabilities_update(sphb);
         if (ret) {
             error_report("Unable to get DMA32 info from VFIO");
@@ -1282,6 +1277,11 @@ static void spapr_phb_realize(DeviceState *dev, Error **errp)
     PCIBus *bus;
     uint64_t msi_window_size = 4096;
 
+    if ((sphb->iommugroupid != -1) &&
+        object_dynamic_cast(OBJECT(sphb), TYPE_SPAPR_PCI_VFIO_HOST_BRIDGE)) {
+        error_report("Warning: iommugroupid is deprecated and will be ignored");
+    }
+
     if (sphb->index != (uint32_t)-1) {
         hwaddr windows_base;
 
diff --git a/hw/ppc/spapr_pci_vfio.c b/hw/ppc/spapr_pci_vfio.c
index f94d8a4..48137d5 100644
--- a/hw/ppc/spapr_pci_vfio.c
+++ b/hw/ppc/spapr_pci_vfio.c
@@ -35,7 +35,7 @@ int spapr_phb_vfio_dma_capabilities_update(sPAPRPHBState *sphb)
     struct vfio_iommu_spapr_tce_info info = { .argsz = sizeof(info) };
     int ret;
 
-    ret = vfio_container_ioctl(&sphb->iommu_as, sphb->iommugroupid,
+    ret = vfio_container_ioctl(&sphb->iommu_as,
                                VFIO_IOMMU_SPAPR_TCE_GET_INFO, &info);
     if (ret) {
         return ret;
@@ -54,8 +54,7 @@ void spapr_phb_vfio_eeh_reenable(sPAPRPHBState *sphb)
         .op    = VFIO_EEH_PE_ENABLE
     };
 
-    vfio_container_ioctl(&sphb->iommu_as,
-                         sphb->iommugroupid, VFIO_EEH_PE_OP, &op);
+    vfio_container_ioctl(&sphb->iommu_as, VFIO_EEH_PE_OP, &op);
 }
 
 int spapr_phb_vfio_eeh_set_option(sPAPRPHBState *sphb,
@@ -81,8 +80,7 @@ int spapr_phb_vfio_eeh_set_option(sPAPRPHBState *sphb,
         return RTAS_OUT_PARAM_ERROR;
     }
 
-    ret = vfio_container_ioctl(&sphb->iommu_as, sphb->iommugroupid,
-                               VFIO_EEH_PE_OP, &op);
+    ret = vfio_container_ioctl(&sphb->iommu_as, VFIO_EEH_PE_OP, &op);
     if (ret < 0) {
         return RTAS_OUT_HW_ERROR;
     }
@@ -96,8 +94,7 @@ int spapr_phb_vfio_eeh_get_state(sPAPRPHBState *sphb, int *state)
     int ret;
 
     op.op = VFIO_EEH_PE_GET_STATE;
-    ret = vfio_container_ioctl(&sphb->iommu_as, sphb->iommugroupid,
-                               VFIO_EEH_PE_OP, &op);
+    ret = vfio_container_ioctl(&sphb->iommu_as, VFIO_EEH_PE_OP, &op);
     if (ret < 0) {
         return RTAS_OUT_PARAM_ERROR;
     }
@@ -170,8 +167,7 @@ int spapr_phb_vfio_eeh_reset(sPAPRPHBState *sphb, int option)
         return RTAS_OUT_PARAM_ERROR;
     }
 
-    ret = vfio_container_ioctl(&sphb->iommu_as, sphb->iommugroupid,
-                               VFIO_EEH_PE_OP, &op);
+    ret = vfio_container_ioctl(&sphb->iommu_as, VFIO_EEH_PE_OP, &op);
     if (ret < 0) {
         return RTAS_OUT_HW_ERROR;
     }
@@ -185,8 +181,7 @@ int spapr_phb_vfio_eeh_configure(sPAPRPHBState *sphb)
     int ret;
 
     op.op = VFIO_EEH_PE_CONFIGURE;
-    ret = vfio_container_ioctl(&sphb->iommu_as, sphb->iommugroupid,
-                               VFIO_EEH_PE_OP, &op);
+    ret = vfio_container_ioctl(&sphb->iommu_as, VFIO_EEH_PE_OP, &op);
     if (ret < 0) {
         return RTAS_OUT_PARAM_ERROR;
     }
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 85ee9b0..a00644e 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -926,35 +926,25 @@ void vfio_put_base_device(VFIODevice *vbasedev)
     close(vbasedev->fd);
 }
 
-static int vfio_container_do_ioctl(AddressSpace *as, int32_t groupid,
-                                   int req, void *param)
+static int vfio_container_do_ioctl(AddressSpace *as, int req, void *param)
 {
-    VFIOGroup *group;
     VFIOContainer *container;
     int ret = -1;
+    VFIOAddressSpace *space = vfio_get_address_space(as);
 
-    group = vfio_get_group(groupid, as);
-    if (!group) {
-        error_report("vfio: group %d not registered", groupid);
-        return ret;
-    }
-
-    container = group->container;
-    if (group->container) {
+    QLIST_FOREACH(container, &space->containers, next) {
         ret = ioctl(container->fd, req, param);
         if (ret < 0) {
             error_report("vfio: failed to ioctl %d to container: ret=%d, %s",
                          _IOC_NR(req) - VFIO_BASE, ret, strerror(errno));
+            return -errno;
         }
     }
 
-    vfio_put_group(group);
-
     return ret;
 }
 
-int vfio_container_ioctl(AddressSpace *as, int32_t groupid,
-                         int req, void *param)
+int vfio_container_ioctl(AddressSpace *as, int req, void *param)
 {
     /* We allow only certain ioctls to the container */
     switch (req) {
@@ -968,5 +958,5 @@ int vfio_container_ioctl(AddressSpace *as, int32_t groupid,
         return -1;
     }
 
-    return vfio_container_do_ioctl(as, groupid, req, param);
+    return vfio_container_do_ioctl(as, req, param);
 }
diff --git a/include/hw/vfio/vfio.h b/include/hw/vfio/vfio.h
index 0b26cd8..e076c14 100644
--- a/include/hw/vfio/vfio.h
+++ b/include/hw/vfio/vfio.h
@@ -3,7 +3,6 @@
 
 #include "qemu/typedefs.h"
 
-extern int vfio_container_ioctl(AddressSpace *as, int32_t groupid,
-                                int req, void *param);
+extern int vfio_container_ioctl(AddressSpace *as, int req, void *param);
 
 #endif
-- 
2.4.0.rc3.8.gfb3e7d5