Hi Vivek,
On 2/12/21 11:58 AM, Vivek Gautam wrote:
> Add a vendor specific structure for domain nesting info for
> arm smmu-v3, and necessary info fields required to populate
> stage1 page tables.
>
> Signed-off-by: Vivek Gautam <[email protected]>
> ---
> include/uapi/linux/iommu.h | 31 +++++++++++++++++++++++++------
> 1 file changed, 25 insertions(+), 6 deletions(-)
>
> diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
> index 4d3d988fa353..5f059bcf7720 100644
> --- a/include/uapi/linux/iommu.h
> +++ b/include/uapi/linux/iommu.h
> @@ -323,7 +323,8 @@ struct iommu_gpasid_bind_data {
> #define IOMMU_GPASID_BIND_VERSION_1 1
> __u32 version;
> #define IOMMU_PASID_FORMAT_INTEL_VTD 1
> -#define IOMMU_PASID_FORMAT_LAST 2
> +#define IOMMU_PASID_FORMAT_ARM_SMMU_V3 2
> +#define IOMMU_PASID_FORMAT_LAST 3
> __u32 format;
> __u32 addr_width;
> #define IOMMU_SVA_GPASID_VAL (1 << 0) /* guest PASID valid */
> @@ -409,6 +410,21 @@ struct iommu_nesting_info_vtd {
> __u64 ecap_reg;
> };
>
> +/*
> + * struct iommu_nesting_info_arm_smmuv3 - Arm SMMU-v3 nesting info.
> + */
> +struct iommu_nesting_info_arm_smmuv3 {
> + __u32 flags;
> + __u16 asid_bits;
> +
> + /* Arm LPAE page table format as per kernel */
> +#define ARM_PGTBL_32_LPAE_S1 (0x0)
> +#define ARM_PGTBL_64_LPAE_S1 (0x2)
Shouldn't it be a bitfield instead as both can be supported (the actual
driver only supports 64b table format though). Does it match matches
IDR0.TTF?
> + __u8 pgtbl_fmt;
So I understand this API is supposed to allow VFIO to expose those info
early enough to the userspace to help configuring the viommu and avoid
errors later on. I wonder how far we want to go on this path. What about
those other caps that impact the STE/CD validity. There may be others...
SMMU_IDR0.CD2L (support of 2 stage CD)
SMMU_IDR0.TTENDIAN (endianness)
SMMU_IDR0.HTTU (if 0 forbids HA/HD setting in the CD)
SMMU_IDR3.STT (impacts T0SZ)
Thanks
Eric
> +
> + __u8 padding[9];
> +};
> +
> /*
> * struct iommu_nesting_info - Information for nesting-capable IOMMU.
> * userspace should check it before using
> @@ -445,11 +461,13 @@ struct iommu_nesting_info_vtd {
> * +---------------+------------------------------------------------------+
> *
> * data struct types defined for @format:
> - * +================================+=====================================+
> - * | @format | data struct |
> - * +================================+=====================================+
> - * | IOMMU_PASID_FORMAT_INTEL_VTD | struct iommu_nesting_info_vtd |
> - * +--------------------------------+-------------------------------------+
> + * +================================+======================================+
> + * | @format | data struct |
> + * +================================+======================================+
> + * | IOMMU_PASID_FORMAT_INTEL_VTD | struct iommu_nesting_info_vtd |
> + * +---------------+-------------------------------------------------------+
> + * | IOMMU_PASID_FORMAT_ARM_SMMU_V3 | struct iommu_nesting_info_arm_smmuv3 |
> + * +--------------------------------+--------------------------------------+
> *
> */
> struct iommu_nesting_info {
> @@ -466,6 +484,7 @@ struct iommu_nesting_info {
> /* Vendor specific data */
> union {
> struct iommu_nesting_info_vtd vtd;
> + struct iommu_nesting_info_arm_smmuv3 smmuv3;
> } vendor;
> };
>
>