diff mbox series

[v1,09/22] vfio/container: Introduce vfio_[attach/detach]_device

Message ID 20230830103754.36461-10-zhenzhong.duan@intel.com
State New
Headers show
Series vfio: Adopt iommufd | expand

Commit Message

Zhenzhong Duan Aug. 30, 2023, 10:37 a.m. UTC 
From: Eric Auger <eric.auger@redhat.com>

We want the VFIO devices to be able to use two different
IOMMU callbacks, the legacy VFIO one and the new iommufd one.

Introduce vfio_[attach/detach]_device which aim at hiding the
underlying IOMMU backend (IOCTLs, datatypes, ...).

Once vfio_attach_device completes, the device is attached
to a security context and its fd can be used. Conversely
When vfio_detach_device completes, the device has been
detached to the security context.

In this patch, only the vfio-pci device gets converted to use
the new API. Subsequent patches will handle other devices.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
---
 hw/vfio/container.c           | 66 +++++++++++++++++++++++++++++++++++
 hw/vfio/pci.c                 | 50 ++++----------------------
 hw/vfio/trace-events          |  2 +-
 include/hw/vfio/vfio-common.h |  3 ++
 4 files changed, 76 insertions(+), 45 deletions(-)

Comments

Eric Auger Sept. 20, 2023, 1:33 p.m. UTC | #1 
Hi Zhenzhong,

In the commit title I would replace vfio/container by vfio/pci to match
next patches

On 8/30/23 12:37, Zhenzhong Duan wrote:
> From: Eric Auger <eric.auger@redhat.com>
>
> We want the VFIO devices to be able to use two different
> IOMMU callbacks, the legacy VFIO one and the new iommufd one.
s/callbacks/backends
>
> Introduce vfio_[attach/detach]_device which aim at hiding the
> underlying IOMMU backend (IOCTLs, datatypes, ...).

At the moment only the implementation based on the legacy
container/group exists. Let's use it from the vfio-pci device.
>
> Once vfio_attach_device completes, the device is attached
> to a security context and its fd can be used. Conversely
> When vfio_detach_device completes, the device has been
> detached to the security context.
from the security context
>
> In this patch, only the vfio-pci device gets converted to use
> the new API. Subsequent patches will handle other devices.
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
>  hw/vfio/container.c           | 66 +++++++++++++++++++++++++++++++++++
>  hw/vfio/pci.c                 | 50 ++++----------------------
>  hw/vfio/trace-events          |  2 +-
>  include/hw/vfio/vfio-common.h |  3 ++
>  4 files changed, 76 insertions(+), 45 deletions(-)
>
> diff --git a/hw/vfio/container.c b/hw/vfio/container.c
> index 175cdbbdff..74556da0c7 100644
> --- a/hw/vfio/container.c
> +++ b/hw/vfio/container.c
> @@ -1083,3 +1083,69 @@ int vfio_eeh_as_op(AddressSpace *as, uint32_t op)
>      }
>      return vfio_eeh_container_op(container, op);
>  }
> +
> +static int vfio_device_groupid(VFIODevice *vbasedev, Error **errp)
> +{
> +    char *tmp, group_path[PATH_MAX], *group_name;
> +    int ret, groupid;
> +    ssize_t len;
> +
> +    tmp = g_strdup_printf("%s/iommu_group", vbasedev->sysfsdev);
> +    len = readlink(tmp, group_path, sizeof(group_path));
> +    g_free(tmp);
> +
> +    if (len <= 0 || len >= sizeof(group_path)) {
> +        ret = len < 0 ? -errno : -ENAMETOOLONG;
> +        error_setg_errno(errp, -ret, "no iommu_group found");
> +        return ret;
> +    }
> +
> +    group_path[len] = 0;
> +
> +    group_name = basename(group_path);
> +    if (sscanf(group_name, "%d", &groupid) != 1) {
> +        error_setg_errno(errp, errno, "failed to read %s", group_path);
> +        return -errno;
> +    }
> +    return groupid;
> +}
> +
> +int vfio_attach_device(char *name, VFIODevice *vbasedev,
> +                       AddressSpace *as, Error **errp)
> +{
> +    int groupid = vfio_device_groupid(vbasedev, errp);
> +    VFIODevice *vbasedev_iter;
> +    VFIOGroup *group;
> +    int ret;
> +
> +    if (groupid < 0) {
> +        return groupid;
> +    }
> +
> +    group = vfio_get_group(groupid, as, errp);
> +    if (!group) {
> +        return -ENOENT;
> +    }
> +
> +    QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
> +        if (strcmp(vbasedev_iter->name, vbasedev->name) == 0) {
> +            error_setg(errp, "device is already attached");
> +            vfio_put_group(group);
> +            return -EBUSY;
> +        }
> +    }
> +    ret = vfio_get_device(group, name, vbasedev, errp);
> +    if (ret) {
> +        vfio_put_group(group);
> +    }
> +
> +    return ret;
> +}
> +
> +void vfio_detach_device(VFIODevice *vbasedev)
> +{
> +    VFIOGroup *group = vbasedev->group;
> +
> +    vfio_put_base_device(vbasedev);
> +    vfio_put_group(group);
> +}
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index a205c6b113..34f65ecd17 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -2828,10 +2828,10 @@ static void vfio_populate_device(VFIOPCIDevice *vdev, Error **errp)
>  
>  static void vfio_put_device(VFIOPCIDevice *vdev)
>  {
> +    vfio_detach_device(&vdev->vbasedev);
> +
>      g_free(vdev->vbasedev.name);
>      g_free(vdev->msix);
> -
> -    vfio_put_base_device(&vdev->vbasedev);
>  }
>  
>  static void vfio_err_notifier_handler(void *opaque)
> @@ -2978,13 +2978,9 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
>  {
>      VFIOPCIDevice *vdev = VFIO_PCI(pdev);
>      VFIODevice *vbasedev = &vdev->vbasedev;
> -    VFIODevice *vbasedev_iter;
> -    VFIOGroup *group;
> -    char *tmp, *subsys, group_path[PATH_MAX], *group_name;
> +    char *tmp, *subsys;
>      Error *err = NULL;
> -    ssize_t len;
>      struct stat st;
> -    int groupid;
>      int i, ret;
>      bool is_mdev;
>      char uuid[UUID_FMT_LEN];
> @@ -3015,38 +3011,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
>      vbasedev->type = VFIO_DEVICE_TYPE_PCI;
>      vbasedev->dev = DEVICE(vdev);
>  
> -    tmp = g_strdup_printf("%s/iommu_group", vbasedev->sysfsdev);
> -    len = readlink(tmp, group_path, sizeof(group_path));
> -    g_free(tmp);
> -
> -    if (len <= 0 || len >= sizeof(group_path)) {
> -        error_setg_errno(errp, len < 0 ? errno : ENAMETOOLONG,
> -                         "no iommu_group found");
> -        goto error;
> -    }
> -
> -    group_path[len] = 0;
> -
> -    group_name = basename(group_path);
> -    if (sscanf(group_name, "%d", &groupid) != 1) {
> -        error_setg_errno(errp, errno, "failed to read %s", group_path);
> -        goto error;
> -    }
> -
> -    trace_vfio_realize(vbasedev->name, groupid);
> -
> -    group = vfio_get_group(groupid, pci_device_iommu_address_space(pdev), errp);
> -    if (!group) {
> -        goto error;
> -    }
> -
> -    QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
> -        if (strcmp(vbasedev_iter->name, vbasedev->name) == 0) {
> -            error_setg(errp, "device is already attached");
> -            vfio_put_group(group);
> -            goto error;
> -        }
> -    }
> +    trace_vfio_realize(vbasedev->name);
>  
>      /*
>       * Mediated devices *might* operate compatibly with discarding of RAM, but
> @@ -3065,7 +3030,6 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
>      if (vbasedev->ram_block_discard_allowed && !is_mdev) {
>          error_setg(errp, "x-balloon-allowed only potentially compatible "
>                     "with mdev devices");
> -        vfio_put_group(group);
>          goto error;
>      }
>  
> @@ -3076,10 +3040,10 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
>          name = g_strdup(vbasedev->name);
>      }
>  
> -    ret = vfio_get_device(group, name, vbasedev, errp);
> +    ret = vfio_attach_device(name, vbasedev,
> +                             pci_device_iommu_address_space(pdev), errp);
>      g_free(name);
>      if (ret) {
> -        vfio_put_group(group);
>          goto error;
>      }
>  
> @@ -3318,7 +3282,6 @@ error:
>  static void vfio_instance_finalize(Object *obj)
>  {
>      VFIOPCIDevice *vdev = VFIO_PCI(obj);
> -    VFIOGroup *group = vdev->vbasedev.group;
>  
>      vfio_display_finalize(vdev);
>      vfio_bars_finalize(vdev);
> @@ -3332,7 +3295,6 @@ static void vfio_instance_finalize(Object *obj)
>       * g_free(vdev->igd_opregion);
>       */
>      vfio_put_device(vdev);
> -    vfio_put_group(group);
>  }
>  
>  static void vfio_exitfn(PCIDevice *pdev)
> diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
> index ee7509e68e..8016d9f0d2 100644
> --- a/hw/vfio/trace-events
> +++ b/hw/vfio/trace-events
> @@ -37,7 +37,7 @@ vfio_pci_hot_reset_dep_devices(int domain, int bus, int slot, int function, int
>  vfio_pci_hot_reset_result(const char *name, const char *result) "%s hot reset: %s"
>  vfio_populate_device_config(const char *name, unsigned long size, unsigned long offset, unsigned long flags) "Device %s config:\n  size: 0x%lx, offset: 0x%lx, flags: 0x%lx"
>  vfio_populate_device_get_irq_info_failure(const char *errstr) "VFIO_DEVICE_GET_IRQ_INFO failure: %s"
> -vfio_realize(const char *name, int group_id) " (%s) group %d"
> +vfio_realize(const char *name) " (%s)"
I am not sure this trace point is useful anymore, without the id. Some
tracepoints shall be BE specific to keep their usefulness and should be
called from container.c/iommufd.c instead of in the generic function.
>  vfio_mdev(const char *name, bool is_mdev) " (%s) is_mdev %d"
>  vfio_add_ext_cap_dropped(const char *name, uint16_t cap, uint16_t offset) "%s 0x%x@0x%x"
>  vfio_pci_reset(const char *name) " (%s)"
> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> index bb7f9fe9c4..a29dfe7723 100644
> --- a/include/hw/vfio/vfio-common.h
> +++ b/include/hw/vfio/vfio-common.h
> @@ -253,6 +253,9 @@ void vfio_put_group(VFIOGroup *group);
>  struct vfio_device_info *vfio_get_device_info(int fd);
>  int vfio_get_device(VFIOGroup *group, const char *name,
>                      VFIODevice *vbasedev, Error **errp);
> +int vfio_attach_device(char *name, VFIODevice *vbasedev,
> +                       AddressSpace *as, Error **errp);
> +void vfio_detach_device(VFIODevice *vbasedev);
>  
>  extern int vfio_kvm_device_fd;
>  
Thanks

Eric
Zhenzhong Duan Sept. 21, 2023, 3:08 a.m. UTC | #2 
>-----Original Message-----
>From: Eric Auger <eric.auger@redhat.com>
>Sent: Wednesday, September 20, 2023 9:33 PM
>Subject: Re: [PATCH v1 09/22] vfio/container: Introduce
>vfio_[attach/detach]_device
>
>Hi Zhenzhong,
>
>In the commit title I would replace vfio/container by vfio/pci to match
>next patches

Make sense, will do.

>
>On 8/30/23 12:37, Zhenzhong Duan wrote:
>> From: Eric Auger <eric.auger@redhat.com>
>>
>> We want the VFIO devices to be able to use two different
>> IOMMU callbacks, the legacy VFIO one and the new iommufd one.
>s/callbacks/backends
>>
>> Introduce vfio_[attach/detach]_device which aim at hiding the
>> underlying IOMMU backend (IOCTLs, datatypes, ...).
>
......

>> diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
>> index ee7509e68e..8016d9f0d2 100644
>> --- a/hw/vfio/trace-events
>> +++ b/hw/vfio/trace-events
>> @@ -37,7 +37,7 @@ vfio_pci_hot_reset_dep_devices(int domain, int bus, int
>slot, int function, int
>>  vfio_pci_hot_reset_result(const char *name, const char *result) "%s hot
>reset: %s"
>>  vfio_populate_device_config(const char *name, unsigned long size, unsigned
>long offset, unsigned long flags) "Device %s config:\n  size: 0x%lx, offset: 0x%lx,
>flags: 0x%lx"
>>  vfio_populate_device_get_irq_info_failure(const char *errstr)
>"VFIO_DEVICE_GET_IRQ_INFO failure: %s"
>> -vfio_realize(const char *name, int group_id) " (%s) group %d"
>> +vfio_realize(const char *name) " (%s)"
>I am not sure this trace point is useful anymore, without the id. Some
>tracepoints shall be BE specific to keep their usefulness and should be
>called from container.c/iommufd.c instead of in the generic function.

Previously I use this trace event just to hint vfio realize starting.
I agree with you that being BE specific could show more useful information.
I'll fix it in v2.

Thanks
Zhenzhong
Cédric Le Goater Sept. 21, 2023, 9:44 a.m. UTC | #3 
On 8/30/23 12:37, Zhenzhong Duan wrote:
> From: Eric Auger <eric.auger@redhat.com>
> 
> We want the VFIO devices to be able to use two different
> IOMMU callbacks, the legacy VFIO one and the new iommufd one.
> 
> Introduce vfio_[attach/detach]_device which aim at hiding the
> underlying IOMMU backend (IOCTLs, datatypes, ...).
> 
> Once vfio_attach_device completes, the device is attached
> to a security context and its fd can be used. Conversely
> When vfio_detach_device completes, the device has been
> detached to the security context.
> 
> In this patch, only the vfio-pci device gets converted to use
> the new API. Subsequent patches will handle other devices.
> 
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
>   hw/vfio/container.c           | 66 +++++++++++++++++++++++++++++++++++
>   hw/vfio/pci.c                 | 50 ++++----------------------
>   hw/vfio/trace-events          |  2 +-
>   include/hw/vfio/vfio-common.h |  3 ++
>   4 files changed, 76 insertions(+), 45 deletions(-)
> 
> diff --git a/hw/vfio/container.c b/hw/vfio/container.c
> index 175cdbbdff..74556da0c7 100644
> --- a/hw/vfio/container.c
> +++ b/hw/vfio/container.c
> @@ -1083,3 +1083,69 @@ int vfio_eeh_as_op(AddressSpace *as, uint32_t op)
>       }
>       return vfio_eeh_container_op(container, op);
>   }
> +
> +static int vfio_device_groupid(VFIODevice *vbasedev, Error **errp)
> +{
> +    char *tmp, group_path[PATH_MAX], *group_name;
> +    int ret, groupid;
> +    ssize_t len;
> +
> +    tmp = g_strdup_printf("%s/iommu_group", vbasedev->sysfsdev);
> +    len = readlink(tmp, group_path, sizeof(group_path));
> +    g_free(tmp);
> +
> +    if (len <= 0 || len >= sizeof(group_path)) {
> +        ret = len < 0 ? -errno : -ENAMETOOLONG;
> +        error_setg_errno(errp, -ret, "no iommu_group found");
> +        return ret;
> +    }
> +
> +    group_path[len] = 0;
> +
> +    group_name = basename(group_path);
> +    if (sscanf(group_name, "%d", &groupid) != 1) {
> +        error_setg_errno(errp, errno, "failed to read %s", group_path);
> +        return -errno;
> +    }
> +    return groupid;
> +}

VFIO has 4 other  routines reading the iommu_group from sysfs :

   vfio_ccw_get_group()
   vfio_ap_get_group()
   vfio_base_device_init()
   sysfs_find_group_file()

which could use this helper. Thanks for introducing it !



> +
> +int vfio_attach_device(char *name, VFIODevice *vbasedev,
> +                       AddressSpace *as, Error **errp)
> +{
> +    int groupid = vfio_device_groupid(vbasedev, errp);
> +    VFIODevice *vbasedev_iter;
> +    VFIOGroup *group;
> +    int ret;
> +
> +    if (groupid < 0) {
> +        return groupid;
> +    }
> +
> +    group = vfio_get_group(groupid, as, errp);
> +    if (!group) {
> +        return -ENOENT;
> +    }
> +
> +    QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
> +        if (strcmp(vbasedev_iter->name, vbasedev->name) == 0) {
> +            error_setg(errp, "device is already attached");
> +            vfio_put_group(group);
> +            return -EBUSY;
> +        }
> +    }
> +    ret = vfio_get_device(group, name, vbasedev, errp);
> +    if (ret) {
> +        vfio_put_group(group);
> +    }
> +
> +    return ret;
> +}
> +
> +void vfio_detach_device(VFIODevice *vbasedev)
> +{
> +    VFIOGroup *group = vbasedev->group;
> +
> +    vfio_put_base_device(vbasedev);
> +    vfio_put_group(group);
> +}
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index a205c6b113..34f65ecd17 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -2828,10 +2828,10 @@ static void vfio_populate_device(VFIOPCIDevice *vdev, Error **errp)
>   
>   static void vfio_put_device(VFIOPCIDevice *vdev)
>   {
> +    vfio_detach_device(&vdev->vbasedev);
> +
>       g_free(vdev->vbasedev.name);
>       g_free(vdev->msix);
> -
> -    vfio_put_base_device(&vdev->vbasedev);
>   }
>   
>   static void vfio_err_notifier_handler(void *opaque)
> @@ -2978,13 +2978,9 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
>   {
>       VFIOPCIDevice *vdev = VFIO_PCI(pdev);
>       VFIODevice *vbasedev = &vdev->vbasedev;
> -    VFIODevice *vbasedev_iter;
> -    VFIOGroup *group;
> -    char *tmp, *subsys, group_path[PATH_MAX], *group_name;
> +    char *tmp, *subsys;
>       Error *err = NULL;
> -    ssize_t len;
>       struct stat st;
> -    int groupid;
>       int i, ret;
>       bool is_mdev;
>       char uuid[UUID_FMT_LEN];
> @@ -3015,38 +3011,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
>       vbasedev->type = VFIO_DEVICE_TYPE_PCI;
>       vbasedev->dev = DEVICE(vdev);
>   
> -    tmp = g_strdup_printf("%s/iommu_group", vbasedev->sysfsdev);
> -    len = readlink(tmp, group_path, sizeof(group_path));
> -    g_free(tmp);
> -
> -    if (len <= 0 || len >= sizeof(group_path)) {
> -        error_setg_errno(errp, len < 0 ? errno : ENAMETOOLONG,
> -                         "no iommu_group found");
> -        goto error;
> -    }
> -
> -    group_path[len] = 0;
> -
> -    group_name = basename(group_path);
> -    if (sscanf(group_name, "%d", &groupid) != 1) {
> -        error_setg_errno(errp, errno, "failed to read %s", group_path);
> -        goto error;
> -    }
> -
> -    trace_vfio_realize(vbasedev->name, groupid);
> -
> -    group = vfio_get_group(groupid, pci_device_iommu_address_space(pdev), errp);
> -    if (!group) {
> -        goto error;
> -    }
> -
> -    QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
> -        if (strcmp(vbasedev_iter->name, vbasedev->name) == 0) {
> -            error_setg(errp, "device is already attached");
> -            vfio_put_group(group);
> -            goto error;
> -        }
> -    }
> +    trace_vfio_realize(vbasedev->name);

I would move the trace event after vfio_attach_device() and print out the group.
Or simply add trace events in vfio_detach/attach_device().

This is a general comment on the VFIO PCI routines which do not use a 'vfio_pci'
prefix and I find it confusing, sometimes. Like this call stack :

   vfio_put_device()
     vfio_detach_device()
       vfio_put_base_device()

I think we should rename vfio_put_device() in vfio_pci_put_device(). This is
not for this series.

Thanks,

C.

>   
>       /*
>        * Mediated devices *might* operate compatibly with discarding of RAM, but
> @@ -3065,7 +3030,6 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
>       if (vbasedev->ram_block_discard_allowed && !is_mdev) {
>           error_setg(errp, "x-balloon-allowed only potentially compatible "
>                      "with mdev devices");
> -        vfio_put_group(group);
>           goto error;
>       }
>   
> @@ -3076,10 +3040,10 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
>           name = g_strdup(vbasedev->name);
>       }
>   
> -    ret = vfio_get_device(group, name, vbasedev, errp);
> +    ret = vfio_attach_device(name, vbasedev,
> +                             pci_device_iommu_address_space(pdev), errp);
>       g_free(name);
>       if (ret) {
> -        vfio_put_group(group);
>           goto error;
>       }
>   
> @@ -3318,7 +3282,6 @@ error:
>   static void vfio_instance_finalize(Object *obj)
>   {
>       VFIOPCIDevice *vdev = VFIO_PCI(obj);
> -    VFIOGroup *group = vdev->vbasedev.group;
>   
>       vfio_display_finalize(vdev);
>       vfio_bars_finalize(vdev);
> @@ -3332,7 +3295,6 @@ static void vfio_instance_finalize(Object *obj)
>        * g_free(vdev->igd_opregion);
>        */
>       vfio_put_device(vdev);
> -    vfio_put_group(group);
>   }
>   
>   static void vfio_exitfn(PCIDevice *pdev)
> diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
> index ee7509e68e..8016d9f0d2 100644
> --- a/hw/vfio/trace-events
> +++ b/hw/vfio/trace-events
> @@ -37,7 +37,7 @@ vfio_pci_hot_reset_dep_devices(int domain, int bus, int slot, int function, int
>   vfio_pci_hot_reset_result(const char *name, const char *result) "%s hot reset: %s"
>   vfio_populate_device_config(const char *name, unsigned long size, unsigned long offset, unsigned long flags) "Device %s config:\n  size: 0x%lx, offset: 0x%lx, flags: 0x%lx"
>   vfio_populate_device_get_irq_info_failure(const char *errstr) "VFIO_DEVICE_GET_IRQ_INFO failure: %s"
> -vfio_realize(const char *name, int group_id) " (%s) group %d"
> +vfio_realize(const char *name) " (%s)"
>   vfio_mdev(const char *name, bool is_mdev) " (%s) is_mdev %d"
>   vfio_add_ext_cap_dropped(const char *name, uint16_t cap, uint16_t offset) "%s 0x%x@0x%x"
>   vfio_pci_reset(const char *name) " (%s)"
> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> index bb7f9fe9c4..a29dfe7723 100644
> --- a/include/hw/vfio/vfio-common.h
> +++ b/include/hw/vfio/vfio-common.h
> @@ -253,6 +253,9 @@ void vfio_put_group(VFIOGroup *group);
>   struct vfio_device_info *vfio_get_device_info(int fd);
>   int vfio_get_device(VFIOGroup *group, const char *name,
>                       VFIODevice *vbasedev, Error **errp);
> +int vfio_attach_device(char *name, VFIODevice *vbasedev,
> +                       AddressSpace *as, Error **errp);
> +void vfio_detach_device(VFIODevice *vbasedev);
>   
>   extern int vfio_kvm_device_fd;
>
Zhenzhong Duan Sept. 21, 2023, 10:26 a.m. UTC | #4 
>-----Original Message-----
>From: Cédric Le Goater <clg@redhat.com>
>Sent: Thursday, September 21, 2023 5:45 PM
>Subject: Re: [PATCH v1 09/22] vfio/container: Introduce
>vfio_[attach/detach]_device
>
>On 8/30/23 12:37, Zhenzhong Duan wrote:
>> From: Eric Auger <eric.auger@redhat.com>
>>
>> We want the VFIO devices to be able to use two different
>> IOMMU callbacks, the legacy VFIO one and the new iommufd one.
>>
>> Introduce vfio_[attach/detach]_device which aim at hiding the
>> underlying IOMMU backend (IOCTLs, datatypes, ...).
>>
>> Once vfio_attach_device completes, the device is attached
>> to a security context and its fd can be used. Conversely
>> When vfio_detach_device completes, the device has been
>> detached to the security context.
>>
>> In this patch, only the vfio-pci device gets converted to use
>> the new API. Subsequent patches will handle other devices.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>> ---
>>   hw/vfio/container.c           | 66 +++++++++++++++++++++++++++++++++++
>>   hw/vfio/pci.c                 | 50 ++++----------------------
>>   hw/vfio/trace-events          |  2 +-
>>   include/hw/vfio/vfio-common.h |  3 ++
>>   4 files changed, 76 insertions(+), 45 deletions(-)
>>
>> diff --git a/hw/vfio/container.c b/hw/vfio/container.c
>> index 175cdbbdff..74556da0c7 100644
>> --- a/hw/vfio/container.c
>> +++ b/hw/vfio/container.c
>> @@ -1083,3 +1083,69 @@ int vfio_eeh_as_op(AddressSpace *as, uint32_t op)
>>       }
>>       return vfio_eeh_container_op(container, op);
>>   }
>> +
>> +static int vfio_device_groupid(VFIODevice *vbasedev, Error **errp)
>> +{
>> +    char *tmp, group_path[PATH_MAX], *group_name;
>> +    int ret, groupid;
>> +    ssize_t len;
>> +
>> +    tmp = g_strdup_printf("%s/iommu_group", vbasedev->sysfsdev);
>> +    len = readlink(tmp, group_path, sizeof(group_path));
>> +    g_free(tmp);
>> +
>> +    if (len <= 0 || len >= sizeof(group_path)) {
>> +        ret = len < 0 ? -errno : -ENAMETOOLONG;
>> +        error_setg_errno(errp, -ret, "no iommu_group found");
>> +        return ret;
>> +    }
>> +
>> +    group_path[len] = 0;
>> +
>> +    group_name = basename(group_path);
>> +    if (sscanf(group_name, "%d", &groupid) != 1) {
>> +        error_setg_errno(errp, errno, "failed to read %s", group_path);
>> +        return -errno;
>> +    }
>> +    return groupid;
>> +}
>
>VFIO has 4 other  routines reading the iommu_group from sysfs :
>
>   vfio_ccw_get_group()
>   vfio_ap_get_group()
>   vfio_base_device_init()
>   sysfs_find_group_file()
>
>which could use this helper. Thanks for introducing it !
>
>
>
>> +
>> +int vfio_attach_device(char *name, VFIODevice *vbasedev,
>> +                       AddressSpace *as, Error **errp)
>> +{
>> +    int groupid = vfio_device_groupid(vbasedev, errp);
>> +    VFIODevice *vbasedev_iter;
>> +    VFIOGroup *group;
>> +    int ret;
>> +
>> +    if (groupid < 0) {
>> +        return groupid;
>> +    }
>> +
>> +    group = vfio_get_group(groupid, as, errp);
>> +    if (!group) {
>> +        return -ENOENT;
>> +    }
>> +
>> +    QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
>> +        if (strcmp(vbasedev_iter->name, vbasedev->name) == 0) {
>> +            error_setg(errp, "device is already attached");
>> +            vfio_put_group(group);
>> +            return -EBUSY;
>> +        }
>> +    }
>> +    ret = vfio_get_device(group, name, vbasedev, errp);
>> +    if (ret) {
>> +        vfio_put_group(group);
>> +    }
>> +
>> +    return ret;
>> +}
>> +
>> +void vfio_detach_device(VFIODevice *vbasedev)
>> +{
>> +    VFIOGroup *group = vbasedev->group;
>> +
>> +    vfio_put_base_device(vbasedev);
>> +    vfio_put_group(group);
>> +}
>> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
>> index a205c6b113..34f65ecd17 100644
>> --- a/hw/vfio/pci.c
>> +++ b/hw/vfio/pci.c
>> @@ -2828,10 +2828,10 @@ static void vfio_populate_device(VFIOPCIDevice
>*vdev, Error **errp)
>>
>>   static void vfio_put_device(VFIOPCIDevice *vdev)
>>   {
>> +    vfio_detach_device(&vdev->vbasedev);
>> +
>>       g_free(vdev->vbasedev.name);
>>       g_free(vdev->msix);
>> -
>> -    vfio_put_base_device(&vdev->vbasedev);
>>   }
>>
>>   static void vfio_err_notifier_handler(void *opaque)
>> @@ -2978,13 +2978,9 @@ static void vfio_realize(PCIDevice *pdev, Error
>**errp)
>>   {
>>       VFIOPCIDevice *vdev = VFIO_PCI(pdev);
>>       VFIODevice *vbasedev = &vdev->vbasedev;
>> -    VFIODevice *vbasedev_iter;
>> -    VFIOGroup *group;
>> -    char *tmp, *subsys, group_path[PATH_MAX], *group_name;
>> +    char *tmp, *subsys;
>>       Error *err = NULL;
>> -    ssize_t len;
>>       struct stat st;
>> -    int groupid;
>>       int i, ret;
>>       bool is_mdev;
>>       char uuid[UUID_FMT_LEN];
>> @@ -3015,38 +3011,7 @@ static void vfio_realize(PCIDevice *pdev, Error
>**errp)
>>       vbasedev->type = VFIO_DEVICE_TYPE_PCI;
>>       vbasedev->dev = DEVICE(vdev);
>>
>> -    tmp = g_strdup_printf("%s/iommu_group", vbasedev->sysfsdev);
>> -    len = readlink(tmp, group_path, sizeof(group_path));
>> -    g_free(tmp);
>> -
>> -    if (len <= 0 || len >= sizeof(group_path)) {
>> -        error_setg_errno(errp, len < 0 ? errno : ENAMETOOLONG,
>> -                         "no iommu_group found");
>> -        goto error;
>> -    }
>> -
>> -    group_path[len] = 0;
>> -
>> -    group_name = basename(group_path);
>> -    if (sscanf(group_name, "%d", &groupid) != 1) {
>> -        error_setg_errno(errp, errno, "failed to read %s", group_path);
>> -        goto error;
>> -    }
>> -
>> -    trace_vfio_realize(vbasedev->name, groupid);
>> -
>> -    group = vfio_get_group(groupid, pci_device_iommu_address_space(pdev),
>errp);
>> -    if (!group) {
>> -        goto error;
>> -    }
>> -
>> -    QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
>> -        if (strcmp(vbasedev_iter->name, vbasedev->name) == 0) {
>> -            error_setg(errp, "device is already attached");
>> -            vfio_put_group(group);
>> -            goto error;
>> -        }
>> -    }
>> +    trace_vfio_realize(vbasedev->name);
>
>I would move the trace event after vfio_attach_device() and print out the group.
>Or simply add trace events in vfio_detach/attach_device().
>
>This is a general comment on the VFIO PCI routines which do not use a 'vfio_pci'
>prefix and I find it confusing, sometimes. Like this call stack :
>
>   vfio_put_device()
>     vfio_detach_device()
>       vfio_put_base_device()
>
>I think we should rename vfio_put_device() in vfio_pci_put_device(). This is
>not for this series.
Good suggestion! I had ever been confused by this function too.
I can help if you have not done that yet.

Thanks
Zhenzhong
diff mbox series

Patch

diff --git a/hw/vfio/container.c b/hw/vfio/container.c
index 175cdbbdff..74556da0c7 100644
--- a/hw/vfio/container.c
+++ b/hw/vfio/container.c
@@ -1083,3 +1083,69 @@  int vfio_eeh_as_op(AddressSpace *as, uint32_t op)
     }
     return vfio_eeh_container_op(container, op);
 }
+
+static int vfio_device_groupid(VFIODevice *vbasedev, Error **errp)
+{
+    char *tmp, group_path[PATH_MAX], *group_name;
+    int ret, groupid;
+    ssize_t len;
+
+    tmp = g_strdup_printf("%s/iommu_group", vbasedev->sysfsdev);
+    len = readlink(tmp, group_path, sizeof(group_path));
+    g_free(tmp);
+
+    if (len <= 0 || len >= sizeof(group_path)) {
+        ret = len < 0 ? -errno : -ENAMETOOLONG;
+        error_setg_errno(errp, -ret, "no iommu_group found");
+        return ret;
+    }
+
+    group_path[len] = 0;
+
+    group_name = basename(group_path);
+    if (sscanf(group_name, "%d", &groupid) != 1) {
+        error_setg_errno(errp, errno, "failed to read %s", group_path);
+        return -errno;
+    }
+    return groupid;
+}
+
+int vfio_attach_device(char *name, VFIODevice *vbasedev,
+                       AddressSpace *as, Error **errp)
+{
+    int groupid = vfio_device_groupid(vbasedev, errp);
+    VFIODevice *vbasedev_iter;
+    VFIOGroup *group;
+    int ret;
+
+    if (groupid < 0) {
+        return groupid;
+    }
+
+    group = vfio_get_group(groupid, as, errp);
+    if (!group) {
+        return -ENOENT;
+    }
+
+    QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
+        if (strcmp(vbasedev_iter->name, vbasedev->name) == 0) {
+            error_setg(errp, "device is already attached");
+            vfio_put_group(group);
+            return -EBUSY;
+        }
+    }
+    ret = vfio_get_device(group, name, vbasedev, errp);
+    if (ret) {
+        vfio_put_group(group);
+    }
+
+    return ret;
+}
+
+void vfio_detach_device(VFIODevice *vbasedev)
+{
+    VFIOGroup *group = vbasedev->group;
+
+    vfio_put_base_device(vbasedev);
+    vfio_put_group(group);
+}
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index a205c6b113..34f65ecd17 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -2828,10 +2828,10 @@  static void vfio_populate_device(VFIOPCIDevice *vdev, Error **errp)
 
 static void vfio_put_device(VFIOPCIDevice *vdev)
 {
+    vfio_detach_device(&vdev->vbasedev);
+
     g_free(vdev->vbasedev.name);
     g_free(vdev->msix);
-
-    vfio_put_base_device(&vdev->vbasedev);
 }
 
 static void vfio_err_notifier_handler(void *opaque)
@@ -2978,13 +2978,9 @@  static void vfio_realize(PCIDevice *pdev, Error **errp)
 {
     VFIOPCIDevice *vdev = VFIO_PCI(pdev);
     VFIODevice *vbasedev = &vdev->vbasedev;
-    VFIODevice *vbasedev_iter;
-    VFIOGroup *group;
-    char *tmp, *subsys, group_path[PATH_MAX], *group_name;
+    char *tmp, *subsys;
     Error *err = NULL;
-    ssize_t len;
     struct stat st;
-    int groupid;
     int i, ret;
     bool is_mdev;
     char uuid[UUID_FMT_LEN];
@@ -3015,38 +3011,7 @@  static void vfio_realize(PCIDevice *pdev, Error **errp)
     vbasedev->type = VFIO_DEVICE_TYPE_PCI;
     vbasedev->dev = DEVICE(vdev);
 
-    tmp = g_strdup_printf("%s/iommu_group", vbasedev->sysfsdev);
-    len = readlink(tmp, group_path, sizeof(group_path));
-    g_free(tmp);
-
-    if (len <= 0 || len >= sizeof(group_path)) {
-        error_setg_errno(errp, len < 0 ? errno : ENAMETOOLONG,
-                         "no iommu_group found");
-        goto error;
-    }
-
-    group_path[len] = 0;
-
-    group_name = basename(group_path);
-    if (sscanf(group_name, "%d", &groupid) != 1) {
-        error_setg_errno(errp, errno, "failed to read %s", group_path);
-        goto error;
-    }
-
-    trace_vfio_realize(vbasedev->name, groupid);
-
-    group = vfio_get_group(groupid, pci_device_iommu_address_space(pdev), errp);
-    if (!group) {
-        goto error;
-    }
-
-    QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
-        if (strcmp(vbasedev_iter->name, vbasedev->name) == 0) {
-            error_setg(errp, "device is already attached");
-            vfio_put_group(group);
-            goto error;
-        }
-    }
+    trace_vfio_realize(vbasedev->name);
 
     /*
      * Mediated devices *might* operate compatibly with discarding of RAM, but
@@ -3065,7 +3030,6 @@  static void vfio_realize(PCIDevice *pdev, Error **errp)
     if (vbasedev->ram_block_discard_allowed && !is_mdev) {
         error_setg(errp, "x-balloon-allowed only potentially compatible "
                    "with mdev devices");
-        vfio_put_group(group);
         goto error;
     }
 
@@ -3076,10 +3040,10 @@  static void vfio_realize(PCIDevice *pdev, Error **errp)
         name = g_strdup(vbasedev->name);
     }
 
-    ret = vfio_get_device(group, name, vbasedev, errp);
+    ret = vfio_attach_device(name, vbasedev,
+                             pci_device_iommu_address_space(pdev), errp);
     g_free(name);
     if (ret) {
-        vfio_put_group(group);
         goto error;
     }
 
@@ -3318,7 +3282,6 @@  error:
 static void vfio_instance_finalize(Object *obj)
 {
     VFIOPCIDevice *vdev = VFIO_PCI(obj);
-    VFIOGroup *group = vdev->vbasedev.group;
 
     vfio_display_finalize(vdev);
     vfio_bars_finalize(vdev);
@@ -3332,7 +3295,6 @@  static void vfio_instance_finalize(Object *obj)
      * g_free(vdev->igd_opregion);
      */
     vfio_put_device(vdev);
-    vfio_put_group(group);
 }
 
 static void vfio_exitfn(PCIDevice *pdev)
diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
index ee7509e68e..8016d9f0d2 100644
--- a/hw/vfio/trace-events
+++ b/hw/vfio/trace-events
@@ -37,7 +37,7 @@  vfio_pci_hot_reset_dep_devices(int domain, int bus, int slot, int function, int
 vfio_pci_hot_reset_result(const char *name, const char *result) "%s hot reset: %s"
 vfio_populate_device_config(const char *name, unsigned long size, unsigned long offset, unsigned long flags) "Device %s config:\n  size: 0x%lx, offset: 0x%lx, flags: 0x%lx"
 vfio_populate_device_get_irq_info_failure(const char *errstr) "VFIO_DEVICE_GET_IRQ_INFO failure: %s"
-vfio_realize(const char *name, int group_id) " (%s) group %d"
+vfio_realize(const char *name) " (%s)"
 vfio_mdev(const char *name, bool is_mdev) " (%s) is_mdev %d"
 vfio_add_ext_cap_dropped(const char *name, uint16_t cap, uint16_t offset) "%s 0x%x@0x%x"
 vfio_pci_reset(const char *name) " (%s)"
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index bb7f9fe9c4..a29dfe7723 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -253,6 +253,9 @@  void vfio_put_group(VFIOGroup *group);
 struct vfio_device_info *vfio_get_device_info(int fd);
 int vfio_get_device(VFIOGroup *group, const char *name,
                     VFIODevice *vbasedev, Error **errp);
+int vfio_attach_device(char *name, VFIODevice *vbasedev,
+                       AddressSpace *as, Error **errp);
+void vfio_detach_device(VFIODevice *vbasedev);
 
 extern int vfio_kvm_device_fd;