Re: [PATCH 1/2] iommu: Report domain nesting info for arm-smmu-v3
From: Auger Eric <eric.auger@redhat.com>
Date: 2021-02-12 18:15:33
Also in:
linux-iommu, lkml, virtualization
Hi Vivek, On 2/12/21 11:58 AM, Vivek Gautam wrote:
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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 <redacted> --- 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
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+ + __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; };
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