Re: [Qemu-devel] [PATCH v4 15/18] spapr_pci_vfio: Enable multiple groups per container

[Alexey Kardashevskiy <aik@ozlabs.ru>]

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On 02/05/2015 03:19 PM, David Gibson wrote:
> On Thu, Jan 29, 2015 at 08:27:27PM +1100, Alexey Kardashevskiy wrote:
>> This enables multiple IOMMU groups in one VFIO container which
>> means that multiple devices from different groups can share the same
>> IOMMU table and locked pages counting can be done once as there is
>> no need to have several containers for two or more groups.
>> 
>> This removes a group id from vfio_container_ioctl(). The kernel
>> support is required for this.
>> 
>> This adds a check that there is just one VFIO container per PHB
>> address space.
>> 
>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> --- 
>> hw/ppc/spapr_pci_vfio.c |  9 +++------ hw/vfio/common.c        | 33
>> +++++++++++++++------------------ include/hw/vfio/vfio.h  |  2 +- 3
>> files changed, 19 insertions(+), 25 deletions(-)
>> 
>> diff --git a/hw/ppc/spapr_pci_vfio.c b/hw/ppc/spapr_pci_vfio.c index
>> b20ac90..257181d 100644 --- a/hw/ppc/spapr_pci_vfio.c +++
>> b/hw/ppc/spapr_pci_vfio.c @@ -33,11 +33,10 @@ static int
>> spapr_pci_vfio_ddw_query(sPAPRPHBState *sphb, uint32_t
>> *dma32_window_size, uint64_t *dma64_window_size) { -
>> sPAPRPHBVFIOState *svphb = SPAPR_PCI_VFIO_HOST_BRIDGE(sphb); struct
>> vfio_iommu_spapr_tce_info info = { .argsz = sizeof(info) }; int
>> ret;
>> 
>> -    ret = vfio_container_ioctl(&sphb->iommu_as,
>> svphb->iommugroupid, +    ret =
>> vfio_container_ioctl(&sphb->iommu_as, VFIO_IOMMU_SPAPR_TCE_GET_INFO,
>> &info);
> 
> 
> Huh.. so vfio_container_ioctl() is actually only used by the
> spapr_tce code.  What's it doing living in the common vfio code?


vfio_container_ioctl() converts the address space to a container fd. The
code outside VFIO does not have an idea about these
container/group/device fds.


> 
>> if (ret) { return ret; @@ -55,7 +54,6 @@ static int
>> spapr_pci_vfio_ddw_create(sPAPRPHBState *sphb, uint32_t liobn, 
>> uint32_t page_shift, uint32_t window_shift, sPAPRTCETable **ptcet) 
>> { -    sPAPRPHBVFIOState *svphb = SPAPR_PCI_VFIO_HOST_BRIDGE(sphb); 
>> struct vfio_iommu_spapr_tce_create create = { .argsz =
>> sizeof(create), .page_shift = page_shift, @@ -65,7 +63,7 @@ static
>> int spapr_pci_vfio_ddw_create(sPAPRPHBState *sphb, uint32_t liobn, 
>> }; int ret;
>> 
>> -    ret = vfio_container_ioctl(&sphb->iommu_as,
>> svphb->iommugroupid, +    ret =
>> vfio_container_ioctl(&sphb->iommu_as, VFIO_IOMMU_SPAPR_TCE_CREATE,
>> &create); if (ret) { return ret; @@ -87,7 +85,6 @@ static int
>> spapr_pci_vfio_ddw_create(sPAPRPHBState *sphb, uint32_t liobn,
>> 
>> static int spapr_pci_vfio_ddw_remove(sPAPRPHBState *sphb,
>> sPAPRTCETable *tcet) { -    sPAPRPHBVFIOState *svphb =
>> SPAPR_PCI_VFIO_HOST_BRIDGE(sphb); struct vfio_iommu_spapr_tce_remove
>> remove = { .argsz = sizeof(remove), .start_addr = tcet->bus_offset 
>> @@ -95,7 +92,7 @@ static int spapr_pci_vfio_ddw_remove(sPAPRPHBState
>> *sphb, sPAPRTCETable *tcet) int ret;
>> 
>> spapr_pci_ddw_remove(sphb, tcet); -    ret =
>> vfio_container_ioctl(&sphb->iommu_as, svphb->iommugroupid, +    ret
>> = vfio_container_ioctl(&sphb->iommu_as, VFIO_IOMMU_SPAPR_TCE_REMOVE,
>> &remove);
>> 
>> return ret; diff --git a/hw/vfio/common.c b/hw/vfio/common.c index
>> 1cafcf8..a26cbae 100644 --- a/hw/vfio/common.c +++
>> b/hw/vfio/common.c @@ -1011,34 +1011,31 @@ void
>> vfio_put_base_device(VFIODevice *vbasedev) close(vbasedev->fd); }
>> 
>> -static int vfio_container_do_ioctl(AddressSpace *as, int32_t
>> groupid, +static int vfio_container_do_ioctl(AddressSpace *as, int
>> req, void *param) { -    VFIOGroup *group; VFIOContainer
>> *container; -    int ret = -1; +    int ret; +    VFIOAddressSpace
>> *space;
>> 
>> -    group = vfio_get_group(groupid, as); -    if (!group) { -
>> error_report("vfio: group %d not registered", groupid); -
>> return ret; -    } +    space = vfio_get_address_space(as); +
>> container = QLIST_FIRST(&space->containers);
>> 
>> -    container = group->container; -    if (group->container) { -
>> ret = ioctl(container->fd, req, param); -        if (ret < 0) { -
>> error_report("vfio: failed to ioctl container: ret=%d, %s", -
>> ret, strerror(errno)); -        } +    if (!container ||
>> QLIST_NEXT(container, next)) { +        error_report("vfio: multiple
>> containers per PHB are not -    supported");
> 
> Shouldn't this be an assert?  It's qemu code that sets up the 
> containers after all.


The VFIO maintainer does not like asserts and I do not want to do things
which he does not like unless I really have to :)


> Also the error message is not right for the case of !container.

Right, that I will fix.


>> +        return -1; }
>> 
>> -    vfio_put_group(group); +    ret = ioctl(container->fd, req,
>> param); +    if (ret < 0) { +        error_report("vfio: failed to
>> ioctl container: ret=%d, %s", +                     ret,
>> strerror(errno)); +    }
>> 
>> return ret; }
>> 
>> -int vfio_container_ioctl(AddressSpace *as, int32_t groupid, +int
>> vfio_container_ioctl(AddressSpace *as, int req, void *param) { /* We
>> allow only certain ioctls to the container */ @@ -1054,5 +1051,5 @@
>> 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..76b5744 100644 --- a/include/hw/vfio/vfio.h +++
>> b/include/hw/vfio/vfio.h @@ -3,7 +3,7 @@
>> 
>> #include "qemu/typedefs.h"
>> 
>> -extern int vfio_container_ioctl(AddressSpace *as, int32_t groupid, 
>> +extern int vfio_container_ioctl(AddressSpace *as, int req, void
>> *param);
>> 
>> #endif
> 


- -- 
Alexey
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