> -----Original Message----- > From: Alex Williamson [mailto:alex.williamson@xxxxxxxxxx] > Sent: 09 January 2019 15:37 > To: Pierre Morel <pmorel@xxxxxxxxxxxxx> > Cc: kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > walling@xxxxxxxxxxxxx; cohuck@xxxxxxxxxx; david@xxxxxxxxxx; > pasic@xxxxxxxxxxxxx; thuth@xxxxxxxxxx; Shameerali Kolothum Thodi > <shameerali.kolothum.thodi@xxxxxxxxxx> > Subject: Re: [PATCH v1 1/2] vfio:iommu: Use capabilities do report IOMMU > informations > > On Wed, 9 Jan 2019 13:41:53 +0100 > Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote: > > > We add a new flag, VFIO_IOMMU_INFO_CAPABILITIES, inside the > > vfio_iommu_type1_info to specify the support for capabilities. > > > > We add a new capability, with id VFIO_IOMMU_INFO_CAP_DMA > > in the capability list of the VFIO_IOMMU_GET_INFO ioctl. > > > > Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx> > > --- > > include/uapi/linux/vfio.h | 9 +++++++++ > > 1 file changed, 9 insertions(+) > > > > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h > > index 8131028..54c4fcb 100644 > > --- a/include/uapi/linux/vfio.h > > +++ b/include/uapi/linux/vfio.h > > @@ -669,6 +669,15 @@ struct vfio_iommu_type1_info { > > __u32 flags; > > #define VFIO_IOMMU_INFO_PGSIZES (1 << 0) /* supported page sizes > info */ > > __u64 iova_pgsizes; /* Bitmap of supported page sizes */ > > +#define VFIO_IOMMU_INFO_CAPABILITIES (1 << 1) /* support capabilities > info */ > > + __u64 cap_offset; /* Offset within info struct of first cap */ > > +}; > > + > > +#define VFIO_IOMMU_INFO_CAP_DMA 1 > > +struct vfio_iommu_cap_dma { > > + struct vfio_info_cap_header header; > > + __u64 dma_start; > > + __u64 dma_end; > > }; > > > > #define VFIO_IOMMU_GET_INFO _IO(VFIO_TYPE, VFIO_BASE + 12) > > Unfortunately for most systems, a simple start and end is not really > sufficient to describe the available IOVA space, there are often > reserved regions intermixed, so this is not really a complete > solution. Shameer tried to solve this last year[1] but we ran into a > road block that Intel IGD devices impose a reserved range of IOVA > spaces reported to the user that conflict with existing assignment of > this device and we haven't figured out yet how to be more selective of > the enforcement of those reserved ranges. Thanks, Right. I had further discussions to unblock this at KVM forum/off-list with Intel folks and was promised some help. IIRC the discussion was at, Kevin/Ashok will take another look on your proposed approach to exclude the RMRR[1] and see whether that is good enough or not. Kevin/Ashok, Please update if you had a chance to look into it. Thanks, Shameer [1]. https://lkml.org/lkml/2018/6/5/897 > Alex > > [1] https://lkml.org/lkml/2018/4/18/293
