diff mbox series

[v2,03/22] vfio: check VFIO_TYPE1_NESTING_IOMMU support

Message ID 1585542301-84087-4-git-send-email-yi.l.liu@intel.com
State New
Headers show
Series intel_iommu: expose Shared Virtual Addressing to VMs | expand

Commit Message

Liu, Yi L March 30, 2020, 4:24 a.m. UTC
VFIO needs to check VFIO_TYPE1_NESTING_IOMMU support with Kernel before
further using it. e.g. requires to check IOMMU UAPI version.

Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Yi Sun <yi.y.sun@linux.intel.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>
---
 hw/vfio/common.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

Comments

Auger Eric March 30, 2020, 9:36 a.m. UTC | #1
Yi,

On 3/30/20 6:24 AM, Liu Yi L wrote:
> VFIO needs to check VFIO_TYPE1_NESTING_IOMMU support with Kernel before
> further using it. e.g. requires to check IOMMU UAPI version.
> 
> Cc: Kevin Tian <kevin.tian@intel.com>
> Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Cc: Peter Xu <peterx@redhat.com>
> Cc: Eric Auger <eric.auger@redhat.com>
> Cc: Yi Sun <yi.y.sun@linux.intel.com>
> Cc: David Gibson <david@gibson.dropbear.id.au>
> Cc: Alex Williamson <alex.williamson@redhat.com>
> Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
> Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>
> ---
>  hw/vfio/common.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index 0b3593b..c276732 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -1157,12 +1157,21 @@ static void vfio_put_address_space(VFIOAddressSpace *space)
>  static int vfio_get_iommu_type(VFIOContainer *container,
>                                 Error **errp)
>  {
> -    int iommu_types[] = { VFIO_TYPE1v2_IOMMU, VFIO_TYPE1_IOMMU,
> +    int iommu_types[] = { VFIO_TYPE1_NESTING_IOMMU,
> +                          VFIO_TYPE1v2_IOMMU, VFIO_TYPE1_IOMMU,
>                            VFIO_SPAPR_TCE_v2_IOMMU, VFIO_SPAPR_TCE_IOMMU };
> -    int i;
> +    int i, version;
>  
>      for (i = 0; i < ARRAY_SIZE(iommu_types); i++) {
>          if (ioctl(container->fd, VFIO_CHECK_EXTENSION, iommu_types[i])) {
> +            if (iommu_types[i] == VFIO_TYPE1_NESTING_IOMMU) {
> +                version = ioctl(container->fd, VFIO_CHECK_EXTENSION,
> +                                VFIO_NESTING_IOMMU_UAPI);
> +                if (version < IOMMU_UAPI_VERSION) {
> +                    info_report("IOMMU UAPI incompatible for nesting");
> +                    continue;
> +                }
> +            }
This means that by default VFIO_TYPE1_NESTING_IOMMU wwould be chosen. I
don't think this what we want. On ARM this would mean that for a
standard VFIO assignment without vIOMMU, SL will be used instead of FL.
This may not be harmless.

For instance, in "[RFC v6 09/24] vfio: Force nested if iommu requires
it", I use nested only if I detect we have a vSMMU. Otherwise I keep the
legacy VFIO_TYPE1v2_IOMMU.

Thanks

Eric
>              return iommu_types[i];
>          }
>      }
> @@ -1278,6 +1287,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
>      }
>  
>      switch (container->iommu_type) {
> +    case VFIO_TYPE1_NESTING_IOMMU:
>      case VFIO_TYPE1v2_IOMMU:
>      case VFIO_TYPE1_IOMMU:
>      {
>
Liu, Yi L March 31, 2020, 6:08 a.m. UTC | #2
Eric,

> From: Auger Eric <eric.auger@redhat.com>
> Sent: Monday, March 30, 2020 5:36 PM
> To: Liu, Yi L <yi.l.liu@intel.com>; qemu-devel@nongnu.org;
> Subject: Re: [PATCH v2 03/22] vfio: check VFIO_TYPE1_NESTING_IOMMU support
> 
> Yi,
> 
> On 3/30/20 6:24 AM, Liu Yi L wrote:
> > VFIO needs to check VFIO_TYPE1_NESTING_IOMMU support with Kernel before
> > further using it. e.g. requires to check IOMMU UAPI version.
> >
> > Cc: Kevin Tian <kevin.tian@intel.com>
> > Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
> > Cc: Peter Xu <peterx@redhat.com>
> > Cc: Eric Auger <eric.auger@redhat.com>
> > Cc: Yi Sun <yi.y.sun@linux.intel.com>
> > Cc: David Gibson <david@gibson.dropbear.id.au>
> > Cc: Alex Williamson <alex.williamson@redhat.com>
> > Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
> > Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>
> > ---
> >  hw/vfio/common.c | 14 ++++++++++++--
> >  1 file changed, 12 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> > index 0b3593b..c276732 100644
> > --- a/hw/vfio/common.c
> > +++ b/hw/vfio/common.c
> > @@ -1157,12 +1157,21 @@ static void
> vfio_put_address_space(VFIOAddressSpace *space)
> >  static int vfio_get_iommu_type(VFIOContainer *container,
> >                                 Error **errp)
> >  {
> > -    int iommu_types[] = { VFIO_TYPE1v2_IOMMU, VFIO_TYPE1_IOMMU,
> > +    int iommu_types[] = { VFIO_TYPE1_NESTING_IOMMU,
> > +                          VFIO_TYPE1v2_IOMMU, VFIO_TYPE1_IOMMU,
> >                            VFIO_SPAPR_TCE_v2_IOMMU, VFIO_SPAPR_TCE_IOMMU };
> > -    int i;
> > +    int i, version;
> >
> >      for (i = 0; i < ARRAY_SIZE(iommu_types); i++) {
> >          if (ioctl(container->fd, VFIO_CHECK_EXTENSION, iommu_types[i])) {
> > +            if (iommu_types[i] == VFIO_TYPE1_NESTING_IOMMU) {
> > +                version = ioctl(container->fd, VFIO_CHECK_EXTENSION,
> > +                                VFIO_NESTING_IOMMU_UAPI);
> > +                if (version < IOMMU_UAPI_VERSION) {
> > +                    info_report("IOMMU UAPI incompatible for nesting");
> > +                    continue;
> > +                }
> > +            }
> This means that by default VFIO_TYPE1_NESTING_IOMMU wwould be chosen. I
> don't think this what we want. On ARM this would mean that for a
> standard VFIO assignment without vIOMMU, SL will be used instead of FL.
> This may not be harmless.
> 
> For instance, in "[RFC v6 09/24] vfio: Force nested if iommu requires
> it", I use nested only if I detect we have a vSMMU. Otherwise I keep the
> legacy VFIO_TYPE1v2_IOMMU.
> 
Good point. I also replied in your patch.

Regards,
Yi Liu
diff mbox series

Patch

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 0b3593b..c276732 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -1157,12 +1157,21 @@  static void vfio_put_address_space(VFIOAddressSpace *space)
 static int vfio_get_iommu_type(VFIOContainer *container,
                                Error **errp)
 {
-    int iommu_types[] = { VFIO_TYPE1v2_IOMMU, VFIO_TYPE1_IOMMU,
+    int iommu_types[] = { VFIO_TYPE1_NESTING_IOMMU,
+                          VFIO_TYPE1v2_IOMMU, VFIO_TYPE1_IOMMU,
                           VFIO_SPAPR_TCE_v2_IOMMU, VFIO_SPAPR_TCE_IOMMU };
-    int i;
+    int i, version;
 
     for (i = 0; i < ARRAY_SIZE(iommu_types); i++) {
         if (ioctl(container->fd, VFIO_CHECK_EXTENSION, iommu_types[i])) {
+            if (iommu_types[i] == VFIO_TYPE1_NESTING_IOMMU) {
+                version = ioctl(container->fd, VFIO_CHECK_EXTENSION,
+                                VFIO_NESTING_IOMMU_UAPI);
+                if (version < IOMMU_UAPI_VERSION) {
+                    info_report("IOMMU UAPI incompatible for nesting");
+                    continue;
+                }
+            }
             return iommu_types[i];
         }
     }
@@ -1278,6 +1287,7 @@  static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
     }
 
     switch (container->iommu_type) {
+    case VFIO_TYPE1_NESTING_IOMMU:
     case VFIO_TYPE1v2_IOMMU:
     case VFIO_TYPE1_IOMMU:
     {