Re: [Qemu-devel] [PATCH v7 2/4] vfio: Add vfio_container_spapr_get_info()

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 06/06/2014 05:27 AM, Alex Williamson wrote:
> On Thu, 2014-06-05 at 15:49 +1000, Alexey Kardashevskiy wrote:
>> To perform DMA mapping via TCE table correctly, the guest must
>> know where DMA window is located on the PCI bus. A hypervisor is
>> expected to provide such information. Since QEMU has no control
>> over this setting, we need a way to obtain a start address and size
>> from the host VFIO driver.
>>
>> This adds a helper which returns the default DMA window properties
>> for the specific IOMMU group. The upstream kernel implements this ioctl
>> already.
> 
> Couldn't this be done with Gavin's vfio_pci_container_ioctl()?  Thanks,


Good point, I missed that. I'll merge two helpers into one and repost, then
Gavin will use it.


> 
> Alex
> 
> 
>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>> ---
>> Changes:
>> v7:
>> * do not return a group fd from the helper
>>
>> v6:
>> * added dup() to protect group_fd from accidental disposal
>>
>> v5:
>> * reworked to reflect change in vfio_get_group() from one
>> of previous patches change
>>
>> v4:
>> * fixed possible leaks on error paths
>> ---
>>  hw/misc/vfio.c         | 36 ++++++++++++++++++++++++++++++++++++
>>  include/hw/misc/vfio.h | 11 +++++++++++
>>  2 files changed, 47 insertions(+)
>>  create mode 100644 include/hw/misc/vfio.h
>>
>> diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
>> index 7437c2e..99141f3 100644
>> --- a/hw/misc/vfio.c
>> +++ b/hw/misc/vfio.c
>> @@ -39,6 +39,7 @@
>>  #include "qemu/range.h"
>>  #include "sysemu/kvm.h"
>>  #include "sysemu/sysemu.h"
>> +#include "hw/misc/vfio.h"
>>  
>>  /* #define DEBUG_VFIO */
>>  #ifdef DEBUG_VFIO
>> @@ -4318,3 +4319,38 @@ static void register_vfio_pci_dev_type(void)
>>  }
>>  
>>  type_init(register_vfio_pci_dev_type)
>> +
>> +int vfio_container_spapr_get_info(AddressSpace *as,
>> +                                  int32_t groupid,
>> +                                  struct vfio_iommu_spapr_tce_info *info)
>> +{
>> +    VFIOGroup *group;
>> +    VFIOContainer *container;
>> +    int ret, fd;
>> +
>> +    group = vfio_get_group(groupid, as);
>> +    if (!group) {
>> +        return -1;
>> +    }
>> +    container = group->container;
>> +    if (!group->container) {
>> +        goto put_group_exit;
>> +    }
>> +    fd = container->fd;
>> +    if (!ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_IOMMU)) {
>> +        goto put_group_exit;
>> +    }
>> +    ret = ioctl(fd, VFIO_IOMMU_SPAPR_TCE_GET_INFO, info);
>> +    if (ret) {
>> +        error_report("vfio: failed to get iommu info for container: %s",
>> +                     strerror(errno));
>> +        goto put_group_exit;
>> +    }
>> +
>> +    return 0;
>> +
>> +put_group_exit:
>> +    vfio_put_group(group);
>> +
>> +    return -1;
>> +}
>> diff --git a/include/hw/misc/vfio.h b/include/hw/misc/vfio.h
>> new file mode 100644
>> index 0000000..e82f5a3
>> --- /dev/null
>> +++ b/include/hw/misc/vfio.h
>> @@ -0,0 +1,11 @@
>> +#ifndef VFIO_API_H
>> +#define VFIO_API_H
>> +
>> +#include "qemu/typedefs.h"
>> +#include <linux/vfio.h>
>> +
>> +extern int vfio_container_spapr_get_info(AddressSpace *as,
>> +                                         int32_t groupid,
>> +                                         struct vfio_iommu_spapr_tce_info *info);
>> +
>> +#endif
> 
> 
> 


-- 
Alexey