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

[Alexey Kardashevskiy]

On 04/01/2014 07:09 AM, Alex Williamson wrote:
> On Fri, 2014-03-28 at 17:01 +1100, Alexey Kardashevskiy wrote:
>> 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.
> 
> That doesn't really address the concern.  An x86 chipset puts specific
> devices at a specific address, yet this is not something that we hard
> code into QEMU.  We have config files that define this and tools like
> libvirt know where to put things.  Why is SPAPR special enough to have
> QEMU auto-add an entire sub-hierarchy?  If this is a necessary feature,
> why not make it generic and give x86 the capability as well?

Ok. You are right. spapr_pci_vfio_scan() has to go :)



>>> 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!
> 
> I'm still questioning the value of this code, it just seems to be a
> convenience feature for someone running QEMU from the commandline, which
> has never really been a concern for the rest of QEMU.  Suggest taking
> this patch out of he series since it's not critical path.  Thanks,


I can move  spapr_pci_vfio_scan() to a separate patch or get rid of it at
all  but the rest is still needed to setup the correct IOMMU device. Is
that what you really meant?


> 
> 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