Re: [Qemu-devel] [PATCH v5 10/11] spapr-vfio: add spapr-pci-vfio-host-bridge to support vfio

[Alexey Kardashevskiy]

On 03/20/2014 06:57 AM, Alex Williamson wrote:
> On Wed, 2014-03-12 at 16:52 +1100, Alexey Kardashevskiy wrote:
>> The patch adds a spapr-pci-vfio-host-bridge device type
>> which is a PCI Host Bridge with VFIO support. The new device
>> inherits from the spapr-pci-host-bridge device and adds
>> the following properties:
>>      iommu - IOMMU group ID which represents a Partitionable
>>              Endpoint, QEMU/ppc64 uses a separate PHB for
>>              an IOMMU group so the guest kernel has to have
>>              PCI Domain support enabled.
>>      forceaddr (optional, 0 by default) - forces QEMU to copy
>>              device:function from the host address as
>>              certain guest drivers expect devices to appear in
>>              particular locations;
>>      mf (optional, 0 by default) - forces multifunction bit for
>>              the function #0 of a found device, only makes sense
>>              for multifunction devices and only with the forceaddr
>>              property set. It would not be required if there
>>              was a way to know in advance whether a device is
>>              multifunctional or not.
>>      scan (optional, 1 by default) - if non-zero, the new PHB walks
>>              through all non-bridge devices in the group and tries
>>              adding them to the PHB; if zero, all devices in the group
>>              have to be configured manually via the QEMU command line.
>>
>> Examples of use:
>> 1) Scan and add all devices from IOMMU group with ID=1 to QEMU's PHB #6:
>>      -device spapr-pci-vfio-host-bridge,id=DEVICENAME,iommu=1,index=6
>>
>> 2) Configure and Add 3 functions of a multifunctional device to QEMU:
>> (the NEC PCI USB card is used as an example here):
>>      -device spapr-pci-vfio-host-bridge,id=USB,iommu=4,scan=0,index=7 \
>>      -device vfio-pci,host=4:0:1.0,addr=1.0,bus=USB,multifunction=true
>>      -device vfio-pci,host=4:0:1.1,addr=1.1,bus=USB
>>      -device vfio-pci,host=4:0:1.2,addr=1.2,bus=USB
> 
> I won't pretend to predict the reaction of QEMU device architects to
> this, but it seems like the assembly we expect from config files or
> outside utilities, ex. libvirt.  I don't doubt this makes qemu
> commandline usage more palatable, but it seems contrary to some of the
> other things we do in QEMU with devices.  If this is something we need,
> why is it specific to spapr?  IOMMU group can contain multiple devices
> on any platform.  On x86 we could do something similar with a p2p
> bridge, switch, or root port.


At least at the moment devices are assigned to groups statically on SPAPR,
they cannot be moved between groups at all, so it seems like a reasonable
assumption that the user will not mind putting them all to the same QEMU
instance.

I should probably disable "scan" by default though, that would make more
sense for libvirt.


> BTW, the code skips bridges, but doesn't that mean you'll have a hard
> time with forceaddr as you potentially try to overlay devfn from
> multiple buses onto a single bus?
> It also makes the value of this a bit
> more questionable since it seems to fall apart so easily.  Thanks,

These "forceaddr" and "mf" are rather debug options - at the very beginning
I used to have strong impression that USB NEC PCI device (2xOHCI and
1xEHCI) does not work properly if it is not multifunctional but I was
wrong, just checked. So I'll just remove them as they do not help even me
anymore and that's it. Thanks!


> 
> Alex
> 
>> Signed-off-by: Alexey Kardashevskiy <address@hidden>
>> ---
>> Changes:
>> v5:
>> * added handling of possible failure of spapr_vfio_new_table()
>>
>> v4:
>> * moved IOMMU changes to separate patches
>> * moved spapr-pci-vfio-host-bridge to new file
>> ---
>>  hw/ppc/Makefile.objs        |   2 +-
>>  hw/ppc/spapr_pci_vfio.c     | 206 
>> ++++++++++++++++++++++++++++++++++++++++++++
>>  include/hw/pci-host/spapr.h |  13 +++
>>  3 files changed, 220 insertions(+), 1 deletion(-)
>>  create mode 100644 hw/ppc/spapr_pci_vfio.c
>>
>> diff --git a/hw/ppc/Makefile.objs b/hw/ppc/Makefile.objs
>> index ea747f0..2239192 100644
>> --- a/hw/ppc/Makefile.objs
>> +++ b/hw/ppc/Makefile.objs
>> @@ -3,7 +3,7 @@ obj-y += ppc.o ppc_booke.o
>>  # IBM pSeries (sPAPR)
>>  obj-$(CONFIG_PSERIES) += spapr.o spapr_vio.o spapr_events.o
>>  obj-$(CONFIG_PSERIES) += spapr_hcall.o spapr_iommu.o spapr_rtas.o
>> -obj-$(CONFIG_PSERIES) += spapr_pci.o
>> +obj-$(CONFIG_PSERIES) += spapr_pci.o spapr_pci_vfio.o
>>  # PowerPC 4xx boards
>>  obj-y += ppc405_boards.o ppc4xx_devs.o ppc405_uc.o ppc440_bamboo.o
>>  obj-y += ppc4xx_pci.o
>> diff --git a/hw/ppc/spapr_pci_vfio.c b/hw/ppc/spapr_pci_vfio.c
>> new file mode 100644
>> index 0000000..40f6673
>> --- /dev/null
>> +++ b/hw/ppc/spapr_pci_vfio.c
>> @@ -0,0 +1,206 @@
>> +/*
>> + * QEMU sPAPR PCI host for VFIO
>> + *
>> + * Copyright (c) 2011 Alexey Kardashevskiy, IBM Corporation.
>> + *
>> + * Permission is hereby granted, free of charge, to any person obtaining a 
>> copy
>> + * of this software and associated documentation files (the "Software"), to 
>> deal
>> + * in the Software without restriction, including without limitation the 
>> rights
>> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
>> + * copies of the Software, and to permit persons to whom the Software is
>> + * furnished to do so, subject to the following conditions:
>> + *
>> + * The above copyright notice and this permission notice shall be included 
>> in
>> + * all copies or substantial portions of the Software.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 
>> OR
>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
>> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR 
>> OTHER
>> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
>> FROM,
>> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
>> + * THE SOFTWARE.
>> + */
>> +#include <sys/types.h>
>> +#include <dirent.h>
>> +
>> +#include "hw/hw.h"
>> +#include "hw/ppc/spapr.h"
>> +#include "hw/pci-host/spapr.h"
>> +#include "hw/misc/vfio.h"
>> +#include "hw/pci/pci_bus.h"
>> +#include "trace.h"
>> +#include "qemu/error-report.h"
>> +
>> +/* sPAPR VFIO */
>> +static Property spapr_phb_vfio_properties[] = {
>> +    DEFINE_PROP_INT32("iommu", sPAPRPHBVFIOState, iommugroupid, -1),
>> +    DEFINE_PROP_UINT8("scan", sPAPRPHBVFIOState, scan, 1),
>> +    DEFINE_PROP_UINT8("mf", sPAPRPHBVFIOState, enable_multifunction, 0),
>> +    DEFINE_PROP_UINT8("forceaddr", sPAPRPHBVFIOState, force_addr, 0),
>> +    DEFINE_PROP_END_OF_LIST(),
>> +};
>> +
>> +static void spapr_pci_vfio_scan(sPAPRPHBVFIOState *svphb, Error **errp)
>> +{
>> +    PCIHostState *phb = PCI_HOST_BRIDGE(svphb);
>> +    char *iommupath;
>> +    DIR *dirp;
>> +    struct dirent *entry;
>> +    Error *error = NULL;
>> +
>> +    if (!svphb->scan) {
>> +        trace_spapr_pci("autoscan disabled for ", svphb->phb.dtbusname);
>> +        return;
>> +    }
>> +
>> +    iommupath = g_strdup_printf("/sys/kernel/iommu_groups/%d/devices/",
>> +                                svphb->iommugroupid);
>> +    if (!iommupath) {
>> +        return;
>> +    }
>> +
>> +    dirp = opendir(iommupath);
>> +    if (!dirp) {
>> +        error_report("spapr-vfio: vfio scan failed on opendir: %m");
>> +        g_free(iommupath);
>> +        return;
>> +    }
>> +
>> +    while ((entry = readdir(dirp)) != NULL) {
>> +        Error *err = NULL;
>> +        char *tmp;
>> +        FILE *deviceclassfile;
>> +        unsigned deviceclass = 0, domainid, busid, devid, fnid;
>> +        char addr[32];
>> +        DeviceState *dev;
>> +
>> +        if (sscanf(entry->d_name, "%X:%X:%X.%x",
>> +                   &domainid, &busid, &devid, &fnid) != 4) {
>> +            continue;
>> +        }
>> +
>> +        tmp = g_strdup_printf("%s%s/class", iommupath, entry->d_name);
>> +        trace_spapr_pci("Reading device class from ", tmp);
>> +
>> +        deviceclassfile = fopen(tmp, "r");
>> +        if (deviceclassfile) {
>> +            int ret = fscanf(deviceclassfile, "%x", &deviceclass);
>> +            fclose(deviceclassfile);
>> +            if (ret != 1) {
>> +                continue;
>> +            }
>> +        }
>> +        g_free(tmp);
>> +
>> +        if (!deviceclass) {
>> +            continue;
>> +        }
>> +        if ((deviceclass >> 16) == (PCI_CLASS_BRIDGE_OTHER >> 8)) {
>> +            /* Skip bridges */
>> +            continue;
>> +        }
>> +        trace_spapr_pci("Creating device from ", entry->d_name);
>> +
>> +        dev = qdev_create(&phb->bus->qbus, "vfio-pci");
>> +        if (!dev) {
>> +            trace_spapr_pci("failed to create vfio-pci", entry->d_name);
>> +            continue;
>> +        }
>> +        object_property_parse(OBJECT(dev), entry->d_name, "host", &err);
>> +        if (err != NULL) {
>> +            object_unref(OBJECT(dev));
>> +            continue;
>> +        }
>> +        if (svphb->force_addr) {
>> +            snprintf(addr, sizeof(addr), "%x.%x", devid, fnid);
>> +            err = NULL;
>> +            object_property_parse(OBJECT(dev), addr, "addr", &err);
>> +            if (err != NULL) {
>> +                object_unref(OBJECT(dev));
>> +                continue;
>> +            }
>> +        }
>> +        if (svphb->enable_multifunction) {
>> +            qdev_prop_set_bit(dev, "multifunction", 1);
>> +        }
>> +        object_property_set_bool(OBJECT(dev), true, "realized", &error);
>> +        if (error) {
>> +            object_unref(OBJECT(dev));
>> +            error_propagate(errp, error);
>> +            break;
>> +        }
>> +    }
>> +    closedir(dirp);
>> +    g_free(iommupath);
>> +}
>> +
>> +static void spapr_phb_vfio_finish_realize(sPAPRPHBState *sphb, Error **errp)
>> +{
>> +    sPAPRPHBVFIOState *svphb = SPAPR_PCI_VFIO_HOST_BRIDGE(sphb);
>> +    struct vfio_iommu_spapr_tce_info info = { .argsz = sizeof(info) };
>> +    int ret;
>> +    Error *error = NULL;
>> +
>> +    if (svphb->iommugroupid == -1) {
>> +        error_setg(errp, "Wrong IOMMU group ID %d", svphb->iommugroupid);
>> +        return;
>> +    }
>> +
>> +    svphb->phb.tcet = spapr_vfio_new_table(DEVICE(sphb), 
>> svphb->phb.dma_liobn);
>> +
>> +    if (!svphb->phb.tcet) {
>> +        error_setg(errp, "spapr-vfio: failed to create VFIO TCE table");
>> +        return;
>> +    }
>> +
>> +    address_space_init(&sphb->iommu_as, spapr_tce_get_iommu(sphb->tcet),
>> +                       sphb->dtbusname);
>> +
>> +    ret = vfio_container_spapr_get_info(&svphb->phb.iommu_as,
>> +                                        sphb->dma_liobn, 
>> svphb->iommugroupid,
>> +                                        &info);
>> +    if (ret) {
>> +        error_setg_errno(errp, -ret,
>> +                         "spapr-vfio: get info from container failed");
>> +        return;
>> +    }
>> +
>> +    svphb->phb.dma_window_start = info.dma32_window_start;
>> +    svphb->phb.dma_window_size = info.dma32_window_size;
>> +
>> +    spapr_pci_vfio_scan(svphb, &error);
>> +    if (error) {
>> +        error_propagate(errp, error);
>> +    }
>> +}
>> +
>> +static void spapr_phb_vfio_reset(DeviceState *qdev)
>> +{
>> +    /* Do nothing */
>> +}
>> +
>> +static void spapr_phb_vfio_class_init(ObjectClass *klass, void *data)
>> +{
>> +    DeviceClass *dc = DEVICE_CLASS(klass);
>> +    sPAPRPHBClass *spc = SPAPR_PCI_HOST_BRIDGE_CLASS(klass);
>> +
>> +    dc->props = spapr_phb_vfio_properties;
>> +    dc->reset = spapr_phb_vfio_reset;
>> +    spc->finish_realize = spapr_phb_vfio_finish_realize;
>> +}
>> +
>> +static const TypeInfo spapr_phb_vfio_info = {
>> +    .name          = TYPE_SPAPR_PCI_VFIO_HOST_BRIDGE,
>> +    .parent        = TYPE_SPAPR_PCI_HOST_BRIDGE,
>> +    .instance_size = sizeof(sPAPRPHBVFIOState),
>> +    .class_init    = spapr_phb_vfio_class_init,
>> +    .class_size    = sizeof(sPAPRPHBClass),
>> +};
>> +
>> +static void spapr_pci_vfio_register_types(void)
>> +{
>> +    type_register_static(&spapr_phb_vfio_info);
>> +}
>> +
>> +type_init(spapr_pci_vfio_register_types)
>> diff --git a/include/hw/pci-host/spapr.h b/include/hw/pci-host/spapr.h
>> index 0f428a1..18acb67 100644
>> --- a/include/hw/pci-host/spapr.h
>> +++ b/include/hw/pci-host/spapr.h
>> @@ -30,10 +30,14 @@
>>  #define SPAPR_MSIX_MAX_DEVS 32
>>  
>>  #define TYPE_SPAPR_PCI_HOST_BRIDGE "spapr-pci-host-bridge"
>> +#define TYPE_SPAPR_PCI_VFIO_HOST_BRIDGE "spapr-pci-vfio-host-bridge"
>>  
>>  #define SPAPR_PCI_HOST_BRIDGE(obj) \
>>      OBJECT_CHECK(sPAPRPHBState, (obj), TYPE_SPAPR_PCI_HOST_BRIDGE)
>>  
>> +#define SPAPR_PCI_VFIO_HOST_BRIDGE(obj) \
>> +    OBJECT_CHECK(sPAPRPHBVFIOState, (obj), TYPE_SPAPR_PCI_VFIO_HOST_BRIDGE)
>> +
>>  #define SPAPR_PCI_HOST_BRIDGE_CLASS(klass) \
>>       OBJECT_CLASS_CHECK(sPAPRPHBClass, (klass), TYPE_SPAPR_PCI_HOST_BRIDGE)
>>  #define SPAPR_PCI_HOST_BRIDGE_GET_CLASS(obj) \
>> @@ -41,6 +45,7 @@
>>  
>>  typedef struct sPAPRPHBClass sPAPRPHBClass;
>>  typedef struct sPAPRPHBState sPAPRPHBState;
>> +typedef struct sPAPRPHBVFIOState sPAPRPHBVFIOState;
>>  
>>  struct sPAPRPHBClass {
>>      PCIHostBridgeClass parent_class;
>> @@ -78,6 +83,14 @@ struct sPAPRPHBState {
>>      QLIST_ENTRY(sPAPRPHBState) list;
>>  };
>>  
>> +struct sPAPRPHBVFIOState {
>> +    sPAPRPHBState phb;
>> +
>> +    struct VFIOContainer *container;
>> +    int32_t iommugroupid;
>> +    uint8_t scan, enable_multifunction, force_addr;
>> +};
>> +
>>  #define SPAPR_PCI_BASE_BUID          0x800000020000000ULL
>>  
>>  #define SPAPR_PCI_WINDOW_BASE        0x10000000000ULL
> 
> 
> 


-- 
Alexey