Re: [Qemu-devel] [PATCH] vfio-powerpc: added VFIO support (v4)

[Alex Williamson]

On Wed, 2012-07-18 at 21:09 +1000, Alexey Kardashevskiy wrote:
> It literally does the following:
> 
> 1. POWERPC IOMMU support (the kernel counterpart is required)
> 
> 2. The patch assumes that IOAPIC calls are going to be replaced
> with something generic.
> 
> 3. Added sPAPRVFIOData (hw/spapr_iommu_vfio.h) which describes
> the interface between VFIO and sPAPR IOMMU.
> 
> 4. Change sPAPR PHB to scan the PCI bus which is used for
> the IOMMU-VFIO group. Now it is enough to add the following to
> the QEMU command line to get VFIO up with all the devices from
> IOMMU group with id=3:
> -device spapr-pci-host-bridge,busname=E1000E,buid=0x3,iommu=3,\
>  
> mem_win_addr=0x230000000000,io_win_addr=0x240000000000,msi_win_addr=0x250000000000
> 
> WIth the pathes posted today a bit earlier, this patch fully supports
> VFIO what includes MSIX as well.
> 
> ps. yes, I know that linux_vfio.h has moved, will fix it later :)
> 
> Signed-off-by: Alexey Kardashevskiy <address@hidden>
> ---
>  hw/linux-vfio.h       |   26 +++++++++++
>  hw/ppc/Makefile.objs  |    3 ++
>  hw/spapr.h            |    4 ++
>  hw/spapr_iommu.c      |   62 ++++++++++++++++++++++++-
>  hw/spapr_iommu_vfio.h |   34 ++++++++++++++
>  hw/spapr_pci.c        |  124 
> +++++++++++++++++++++++++++++++++++++++++++++++--
>  hw/spapr_pci.h        |    6 +++
>  hw/vfio_pci.c         |   64 +++++++++++++++++++++++++
>  hw/vfio_pci.h         |    2 +
>  trace-events          |    1 +
>  10 files changed, 320 insertions(+), 6 deletions(-)
>  create mode 100644 hw/spapr_iommu_vfio.h
> 
> diff --git a/hw/linux-vfio.h b/hw/linux-vfio.h
> index 300d49b..27a0501 100644
> --- a/hw/linux-vfio.h
> +++ b/hw/linux-vfio.h
> @@ -442,4 +442,30 @@ struct vfio_iommu_type1_dma_unmap {
>  
>  #define VFIO_IOMMU_UNMAP_DMA _IO(VFIO_TYPE, VFIO_BASE + 14)
>  
> +/*
> + * Interface to SPAPR TCE (POWERPC Book3S)
> + */
> +#define SPAPR_TCE_IOMMU         2
> +
> +struct tce_iommu_info {
> +    __u32 argsz;
> +    __u32 flags;
> +    __u32 dma32_window_start;
> +    __u32 dma32_window_size;
> +    __u64 dma64_window_start;
> +    __u64 dma64_window_size;
> +};
> +
> +#define SPAPR_TCE_IOMMU_GET_INFO        _IO(VFIO_TYPE, VFIO_BASE + 12)
> +
> +struct tce_iommu_dma_map {
> +    __u32 argsz;
> +    __u32 flags;
> +    __u64 va;
> +    __u64 dmaaddr;
> +};
> +
> +#define SPAPR_TCE_IOMMU_MAP_DMA         _IO(VFIO_TYPE, VFIO_BASE + 13)
> +#define SPAPR_TCE_IOMMU_UNMAP_DMA       _IO(VFIO_TYPE, VFIO_BASE + 14)
> +
>  #endif /* VFIO_H */
> diff --git a/hw/ppc/Makefile.objs b/hw/ppc/Makefile.objs
> index f573a95..c46a049 100644
> --- a/hw/ppc/Makefile.objs
> +++ b/hw/ppc/Makefile.objs
> @@ -25,4 +25,7 @@ obj-$(CONFIG_FDT) += ../device_tree.o
>  # Xilinx PPC peripherals
>  obj-y += xilinx_ethlite.o
>  
> +# VFIO PCI device assignment
> +obj-$(CONFIG_VFIO_PCI) += vfio_pci.o
> +
>  obj-y := $(addprefix ../,$(obj-y))
> diff --git a/hw/spapr.h b/hw/spapr.h
> index b37f337..0c15c88 100644
> --- a/hw/spapr.h
> +++ b/hw/spapr.h
> @@ -340,4 +340,8 @@ int spapr_dma_dt(void *fdt, int node_off, const char 
> *propname,
>  int spapr_tcet_dma_dt(void *fdt, int node_off, const char *propname,
>                        DMAContext *dma);
>  
> +struct sPAPRVFIOData;
> +void spapr_vfio_init_dma(int group_id, uint32_t liobn,
> +                         struct sPAPRVFIOData *data);
> +
>  #endif /* !defined (__HW_SPAPR_H__) */
> diff --git a/hw/spapr_iommu.c b/hw/spapr_iommu.c
> index 50c288d..0a82842 100644
> --- a/hw/spapr_iommu.c
> +++ b/hw/spapr_iommu.c
> @@ -23,6 +23,8 @@
>  #include "dma.h"
>  
>  #include "hw/spapr.h"
> +#include "hw/spapr_iommu_vfio.h"
> +#include "hw/vfio_pci.h"
>  
>  #include <libfdt.h>
>  
> @@ -183,6 +185,60 @@ static int put_tce_emu(target_ulong liobn, target_ulong 
> ioba, target_ulong tce)
>      return 0;
>  }
>  
> +typedef struct sPAPRVFIOTable {
> +    struct sPAPRVFIOData *data;
> +    uint32_t liobn;
> +    QLIST_ENTRY(sPAPRVFIOTable) list;
> +} sPAPRVFIOTable;
> +
> +QLIST_HEAD(vfio_tce_tables, sPAPRVFIOTable) vfio_tce_tables;
> +
> +void spapr_vfio_init_dma(int group_id, uint32_t liobn,
> +                         struct sPAPRVFIOData *data)
> +{
> +    sPAPRVFIOTable *t;
> +
> +    t = g_malloc0(sizeof(*t));
> +    t->data = data;
> +    t->liobn = liobn;
> +
> +    QLIST_INSERT_HEAD(&vfio_tce_tables, t, list);
> +}
> +
> +static int put_tce_vfio(uint32_t liobn, target_ulong ioba, target_ulong tce)
> +{
> +    sPAPRVFIOTable *t;
> +    struct tce_iommu_dma_map map = {
> +        .argsz = sizeof(map),
> +        .va = 0,
> +        .dmaaddr = ioba,
> +    };
> +
> +    QLIST_FOREACH(t, &vfio_tce_tables, list) {
> +        if (t->liobn != liobn) {
> +            continue;
> +        }
> +        if (!t->data) {
> +            return H_NO_MEM;
> +        }

Why would this ever happen?

> +        if (tce) {
> +            map.va = (uintptr_t)qemu_get_ram_ptr(tce & ~SPAPR_TCE_PAGE_MASK);
> +
> +            if (t->data->map(t->data->groupid, &map)) {

Just pass t->data, this is why the VFIOContainer has a union.

> +                perror("TCE_MAP_DMA");
> +                return H_PARAMETER;
> +            }
> +        } else {
> +            if (t->data->unmap(t->data->groupid, &map)) {
> +                perror("TCE_UNMAP_DMA");
> +                return H_PARAMETER;
> +            }
> +        }
> +        return H_SUCCESS;
> +    }
> +    return H_CONTINUE; /* positive non-zero value */
> +}
> +
>  static target_ulong h_put_tce(CPUPPCState *env, sPAPREnvironment *spapr,
>                                target_ulong opcode, target_ulong *args)
>  {
> @@ -200,7 +256,11 @@ static target_ulong h_put_tce(CPUPPCState *env, 
> sPAPREnvironment *spapr,
>      ioba &= ~(SPAPR_TCE_PAGE_SIZE - 1);
>  
>      ret = put_tce_emu(liobn, ioba, tce);
> -    if (0 >= ret) {
> +    if (ret <= 0) {
> +        return ret ? H_PARAMETER : H_SUCCESS;
> +    }
> +    ret = put_tce_vfio(liobn, ioba, tce);
> +    if (ret <= 0) {
>          return ret ? H_PARAMETER : H_SUCCESS;
>      }
>  #ifdef DEBUG_TCE
> diff --git a/hw/spapr_iommu_vfio.h b/hw/spapr_iommu_vfio.h
> new file mode 100644
> index 0000000..b3d6115
> --- /dev/null
> +++ b/hw/spapr_iommu_vfio.h
> @@ -0,0 +1,34 @@
> +/*
> + * Definitions for VFIO IOMMU implementation for SPAPR TCE.
> + *
> + * Copyright (c) 2012 Alexey Kardashevskiy <address@hidden>
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see 
> <http://www.gnu.org/licenses/>.
> + */
> +
> +#if !defined(__HW_SPAPR_IOMMU_VFIO_H__)
> +#define __HW_SPAPR_IOMMU_VFIO_H__
> +
> +#include "hw/linux-vfio.h"
> +
> +struct sPAPRVFIOData {
> +    int groupid;
> +    struct tce_iommu_info info;

Seems a little lazy to embed this whole thing here, what does anyone
need argsz and flags for later?

> +    int (*map)(int groupid, struct tce_iommu_dma_map *param);
> +    int (*unmap)(int groupid, struct tce_iommu_dma_map *param);

s/int groupid/struct sPAPRVFIOData */ in map/unmap

> +};
> +
> +void spapr_register_vfio_container(struct sPAPRVFIOData *data);
> +
> +#endif
> diff --git a/hw/spapr_pci.c b/hw/spapr_pci.c
> index 88c8f2c..75743e7 100644
> --- a/hw/spapr_pci.c
> +++ b/hw/spapr_pci.c
> @@ -22,6 +22,9 @@
>   * 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.h"
>  #include "pci.h"
>  #include "msi.h"
> @@ -32,7 +35,6 @@
>  #include "exec-memory.h"
>  #include <libfdt.h>
>  #include "trace.h"
> -
>  #include "hw/pci_internals.h"
>  
>  /* Copied from the kernel arch/powerpc/platforms/pseries/msi.c */
> @@ -440,6 +442,12 @@ static void pci_spapr_set_irq(void *opaque, int irq_num, 
> int level)
>                   level);
>  }
>  
> +static int pci_spapr_get_irq(void *opaque, int irq_num)
> +{
> +    sPAPRPHBState *phb = opaque;
> +    return phb->lsi_table[irq_num].dt_irq;
> +}
> +
>  static uint64_t spapr_io_read(void *opaque, target_phys_addr_t addr,
>                                unsigned size)
>  {
> @@ -515,6 +523,93 @@ static DMAContext *spapr_pci_dma_context_fn(PCIBus *bus, 
> void *opaque,
>      return phb->dma;
>  }
>  
> +void spapr_register_vfio_container(struct sPAPRVFIOData *data)
> +{
> +    sPAPRPHBState *phb;
> +
> +    QLIST_FOREACH(phb, &spapr->phbs, list) {
> +        if (phb->iommugroupid == data->groupid) {
> +            phb->vfio_data = *data;
> +            phb->dma_window_start = phb->vfio_data.info.dma32_window_start;
> +            phb->dma_window_size = phb->vfio_data.info.dma32_window_size;
> +            return;
> +        }
> +    }
> +}
> +
> +static int spapr_pci_scan_vfio(sPAPRPHBState *phb)
> +{
> +    char iommupath[256];
> +    DIR *dirp;
> +    struct dirent *entry;
> +
> +    if (!phb->scan) {
> +        trace_spapr_pci("Autoscan disabled for ", phb->dtbusname);
> +        return 0;
> +    }
> +
> +    snprintf(iommupath, sizeof(iommupath),
> +             "/sys/kernel/iommu_groups/%d/devices/", phb->iommugroupid);
> +    dirp = opendir(iommupath);
> +
> +    while ((entry = readdir(dirp)) != 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) {
> +            fscanf(deviceclassfile, "%x", &deviceclass);
> +            fclose(deviceclassfile);
> +        }
> +        g_free(tmp);
> +
> +        if (!deviceclass) {
> +            continue;
> +        }
> +        if ((phb->scan < 2) &&
> +            ((deviceclass >> 16) == (PCI_CLASS_BRIDGE_OTHER >> 8))) {
> +            /* Skip _any_ bridge */
> +            continue;
> +        }
> +        if ((deviceclass == 0xc0310) || (deviceclass == 0xc0320)) {
> +            /* Tweak USB */
> +            phb->force_addr = 1;
> +            phb->enable_multifunction = 1;
> +        }
> +
> +        trace_spapr_pci("Creating devicei from ", entry->d_name);
> +
> +        dev = qdev_create(&phb->host_state.bus->qbus, "vfio-pci");
> +        if (!dev) {
> +            fprintf(stderr, "failed to create vfio-pci\n");
> +            continue;
> +        }
> +        qdev_prop_parse(dev, "host", entry->d_name);
> +        if (phb->force_addr) {
> +            snprintf(addr, sizeof(addr), "%x.%x", devid, fnid);
> +            qdev_prop_parse(dev, "addr", addr);
> +        }
> +        if (phb->enable_multifunction) {
> +            qdev_prop_set_bit(dev, "multifunction", 1);
> +        }
> +        qdev_init_nofail(dev);
> +    }
> +    closedir(dirp);
> +
> +    return 0;
> +}
> +
>  static int spapr_phb_init(SysBusDevice *s)
>  {
>      sPAPRPHBState *phb = DO_UPCAST(sPAPRPHBState, host_state.busdev, s);
> @@ -567,15 +662,13 @@ static int spapr_phb_init(SysBusDevice *s)
>  
>      bus = pci_register_bus(&phb->host_state.busdev.qdev,
>                             phb->busname ? phb->busname : phb->dtbusname,
> -                           pci_spapr_set_irq, NULL, pci_spapr_map_irq, phb,
> +                           pci_spapr_set_irq, pci_spapr_get_irq,
> +                           pci_spapr_map_irq, phb,
>                             &phb->memspace, &phb->iospace,
>                             PCI_DEVFN(0, 0), PCI_NUM_PINS);
>      phb->host_state.bus = bus;
>  
>      phb->dma_liobn = SPAPR_PCI_BASE_LIOBN | (pci_find_domain(bus) << 16);
> -    phb->dma_window_start = 0;
> -    phb->dma_window_size = 0x40000000;
> -    phb->dma = spapr_tce_new_dma_context(phb->dma_liobn, 
> phb->dma_window_size);
>      pci_setup_iommu(bus, spapr_pci_dma_context_fn, phb);
>  
>      QLIST_INSERT_HEAD(&spapr->phbs, phb, list);
> @@ -588,6 +681,19 @@ static int spapr_phb_init(SysBusDevice *s)
>          }
>      }
>  
> +    if (phb->iommugroupid >= 0) {
> +        if (spapr_pci_scan_vfio(phb) < 0) {
> +            return -1;
> +        }
> +        spapr_vfio_init_dma(phb->iommugroupid, phb->dma_liobn, 
> &phb->vfio_data);
> +        return 0;
> +    }
> +
> +    phb->dma_window_start = 0;
> +    phb->dma_window_size = 0x40000000;
> +    phb->dma = spapr_tce_new_dma_context(phb->dma_liobn,
> +                                         phb->dma_window_size);
> +
>      return 0;
>  }
>  
> @@ -599,6 +705,10 @@ static Property spapr_phb_properties[] = {
>      DEFINE_PROP_HEX64("io_win_addr", sPAPRPHBState, io_win_addr, 0),
>      DEFINE_PROP_HEX64("io_win_size", sPAPRPHBState, io_win_size, 0x10000),
>      DEFINE_PROP_HEX64("msi_win_addr", sPAPRPHBState, msi_win_addr, 0),
> +    DEFINE_PROP_INT32("iommu", sPAPRPHBState, iommugroupid, -1),
> +    DEFINE_PROP_UINT8("scan", sPAPRPHBState, scan, 1),
> +    DEFINE_PROP_UINT8("mf", sPAPRPHBState, enable_multifunction, 0),
> +    DEFINE_PROP_UINT8("forceaddr", sPAPRPHBState, force_addr, 0),
>      DEFINE_PROP_END_OF_LIST(),
>  };
>  
> @@ -729,6 +839,10 @@ int spapr_populate_pci_dt(sPAPRPHBState *phb,
>      _FDT(fdt_setprop(fdt, bus_off, "interrupt-map", &interrupt_map,
>                       sizeof(interrupt_map)));
>  
> +    if (!phb->dma_window_size) {
> +        fprintf(stderr, "Unexpected error: DMA window is zero, exiting\n");
> +        exit(1);
> +    }
>      spapr_dma_dt(fdt, bus_off, "ibm,dma-window",
>                   phb->dma_liobn, phb->dma_window_start,
>                   phb->dma_window_size);
> diff --git a/hw/spapr_pci.h b/hw/spapr_pci.h
> index 145071c..ed17053 100644
> --- a/hw/spapr_pci.h
> +++ b/hw/spapr_pci.h
> @@ -26,6 +26,7 @@
>  #include "hw/pci.h"
>  #include "hw/pci_host.h"
>  #include "hw/xics.h"
> +#include "hw/spapr_iommu_vfio.h"
>  
>  #define SPAPR_MSIX_MAX_DEVS 32
>  
> @@ -57,6 +58,11 @@ typedef struct sPAPRPHBState {
>          int nvec;
>      } msi_table[SPAPR_MSIX_MAX_DEVS];
>  
> +    struct sPAPRVFIOData vfio_data;
> +    int32_t iommugroupid;
> +    uint8_t scan; /* 0 don't scan 1 scan only devices 2 scan everything */
> +    uint8_t enable_multifunction, force_addr;
> +
>      QLIST_ENTRY(sPAPRPHBState) list;
>  } sPAPRPHBState;
>  
> diff --git a/hw/vfio_pci.c b/hw/vfio_pci.c
> index 0ad4761..0023d41 100644
> --- a/hw/vfio_pci.c
> +++ b/hw/vfio_pci.c
> @@ -43,6 +43,7 @@
>  #include "range.h"
>  #include "vfio_pci.h"
>  #include "linux-vfio.h"
> +#include "hw/spapr_iommu_vfio.h"
>  
>  //#define DEBUG_VFIO
>  #ifdef DEBUG_VFIO
> @@ -55,6 +56,8 @@
>  
>  #define MSIX_CAP_LENGTH 12
>  
> +static VFIOGroup *vfio_get_group(int groupid);
> +

Unnecessary, because...

>  static QLIST_HEAD(, VFIOContainer)
>      container_list = QLIST_HEAD_INITIALIZER(container_list);
>  
> @@ -1088,6 +1091,31 @@ static void vfio_listener_release(VFIOContainer 
> *container)
>  }
>  
>  /*
> + * sPAPR TCE DMA interface
> + */
> +static int spapr_tce_map(int groupid, struct tce_iommu_dma_map *param)
> +{
> +    VFIOGroup *group = vfio_get_group(groupid);
> +
> +    if (!group || !group->container) {
> +        return -1;
> +    }

This should be:

static int spapr_tce_map(sPAPRVFIOData *spapr_data, struct tce_iommu_dma_map 
*param)
{
    VFIOContainer *container;

    container = container_of(spapr_data, VFIOContainer, iommu_data.spapr);

    return ioctl(container->fd, ....
}


> +
> +    return ioctl(group->container->fd, SPAPR_TCE_IOMMU_MAP_DMA, param);
> +}
> +
> +static int spapr_tce_unmap(int groupid, struct tce_iommu_dma_map *param)
> +{
> +    VFIOGroup *group = vfio_get_group(groupid);
> +
> +    if (!group || !group->container) {
> +        return -1;
> +    }
> +
> +    return ioctl(group->container->fd, SPAPR_TCE_IOMMU_UNMAP_DMA, param);
> +}
> +
> +/*
>   * Interrupt setup
>   */
>  static void vfio_disable_interrupts(VFIODevice *vdev)
> @@ -1590,6 +1618,42 @@ static int vfio_connect_container(VFIOGroup *group)
>          memory_listener_register(&container->iommu_data.listener,
>                                   get_system_memory());
>  
> +    } else if (ioctl(fd, VFIO_CHECK_EXTENSION, SPAPR_TCE_IOMMU)) {
> +        ret = ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd);
> +        if (ret) {
> +            error_report("vfio: failed to set group container: %s\n",
> +                         strerror(errno));
> +            g_free(container);
> +            close(fd);
> +            return -1;
> +        }
> +
> +        ret = ioctl(fd, VFIO_SET_IOMMU, SPAPR_TCE_IOMMU);
> +        if (ret) {
> +            error_report("vfio: failed to set iommu for container: %s\n",
> +                         strerror(errno));
> +            g_free(container);
> +            close(fd);
> +            return -1;
> +        }
> +
> +        container->iommu_data.spapr.info.argsz =
> +                sizeof(container->iommu_data.spapr.info);
> +        ret = ioctl(fd, SPAPR_TCE_IOMMU_GET_INFO,
> +                    &container->iommu_data.spapr.info);
> +        if (ret) {
> +            error_report("vfio: failed to get iommu info for container: 
> %s\n",
> +                         strerror(errno));
> +            g_free(container);
> +            close(fd);
> +            return -1;
> +        }
> +
> +        container->iommu_data.spapr.map = spapr_tce_map;
> +        container->iommu_data.spapr.unmap = spapr_tce_unmap;
> +        container->iommu_data.spapr.groupid = group->groupid;

This at least deserves a comment because x86 doesn't have a 1:1 mapping
of container to groupid.  I really think it might make more sense to
pass a PCIBus here instead of a groupid.  Whatever you choose, this
shouldn't be part of sPAPRVFIOData, it should be another parameter to
spapr_register_vfio_container.

> +        spapr_register_vfio_container(&container->iommu_data.spapr);
> +
>      } else {
>          error_report("vfio: No available IOMMU models\n");
>          g_free(container);
> diff --git a/hw/vfio_pci.h b/hw/vfio_pci.h
> index 00bb3dd..ddb5332 100644
> --- a/hw/vfio_pci.h
> +++ b/hw/vfio_pci.h
> @@ -6,6 +6,7 @@
>  #include "pci.h"
>  #include "ioapic.h"
>  #include "event_notifier.h"
> +#include "hw/spapr_iommu_vfio.h"
>  
>  typedef struct VFIOPCIHostDevice {
>      uint16_t seg;
> @@ -59,6 +60,7 @@ typedef struct VFIOContainer {
>      struct {
>          union {
>              MemoryListener listener;
> +            struct sPAPRVFIOData spapr;
>          };
>          void (*release)(struct VFIOContainer *);
>      } iommu_data;
> diff --git a/trace-events b/trace-events
> index e548f86..9100591 100644
> --- a/trace-events
> +++ b/trace-events
> @@ -848,6 +848,7 @@ qxl_render_guest_primary_resized(int32_t width, int32_t 
> height, int32_t stride,
>  qxl_render_update_area_done(void *cookie) "%p"
>  
>  # hw/spapr_pci.c
> +spapr_pci(const char *msg1, const char *msg2) "%s%s"
>  spapr_pci_msi(const char *msg, uint32_t n, uint32_t ca) "%s (device#%d, 
> cfg=%x)"
>  spapr_pci_msi_setup(const char *name, unsigned vector, uint64_t addr) 
> "dev\"%s\" vector %u, addr=%"PRIx64
>  spapr_pci_rtas_ibm_change_msi(unsigned func, unsigned req) "func %u, 
> requested %u"