[v5] Add Intel VT-d nested translation

[PATCH v5 07/11] iommufd: Add data structure for Intel VT-d stage-1 cache invalidation

Posted by Yi Liu 1 year, 11 months ago

This adds the data structure for flushing iotlb for the nested domain
allocated with IOMMU_HWPT_TYPE_VTD_S1 type.

This only supports invalidating IOTLB, but no for device-TLB as device-TLB
invalidation will be covered automatically in the IOTLB invalidation if the
underlying IOMMU driver has enabled ATS for the affected device.

Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
 include/uapi/linux/iommufd.h | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 18a502e206c3..3050efbceb57 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -510,6 +510,40 @@ struct iommu_hw_info {
 };
 #define IOMMU_GET_HW_INFO _IO(IOMMUFD_TYPE, IOMMUFD_CMD_GET_HW_INFO)
 
+/**
+ * enum iommu_hwpt_vtd_s1_invalidate_flags - Flags for Intel VT-d
+ *                                           stage-1 cache invalidation
+ * @IOMMU_VTD_QI_FLAGS_LEAF: The LEAF flag indicates whether only the
+ *                           leaf PTE caching needs to be invalidated
+ *                           and other paging structure caches can be
+ *                           preserved.
+ */
+enum iommu_hwpt_vtd_s1_invalidate_flags {
+	IOMMU_VTD_QI_FLAGS_LEAF = 1 << 0,
+};
+
+/**
+ * struct iommu_hwpt_vtd_s1_invalidate - Intel VT-d cache invalidation
+ *                                       (IOMMU_HWPT_TYPE_VTD_S1)
+ * @addr: The start address of the addresses to be invalidated.
+ * @npages: Number of contiguous 4K pages to be invalidated.
+ * @flags: Combination of enum iommu_hwpt_vtd_s1_invalidate_flags
+ * @__reserved: Must be 0
+ *
+ * The Intel VT-d specific invalidation data for user-managed stage-1 cache
+ * invalidation under nested translation. Userspace uses this structure to
+ * tell host about the impacted caches after modifying the stage-1 page table.
+ *
+ * Invalidating all the caches related to the page table by setting @addr
+ * to be 0 and @npages to be __aligned_u64(-1).
+ */
+struct iommu_hwpt_vtd_s1_invalidate {
+	__aligned_u64 addr;
+	__aligned_u64 npages;
+	__u32 flags;
+	__u32 __reserved;
+};
+
 /**
  * struct iommu_hwpt_invalidate - ioctl(IOMMU_HWPT_INVALIDATE)
  * @size: sizeof(struct iommu_hwpt_invalidate)
-- 
2.34.1

RE: [PATCH v5 07/11] iommufd: Add data structure for Intel VT-d stage-1 cache invalidation

Posted by Tian, Kevin 1 year, 11 months ago

> From: Liu, Yi L <yi.l.liu@intel.com>
> Sent: Thursday, September 21, 2023 3:54 PM
> 
> +/**
> + * enum iommu_hwpt_vtd_s1_invalidate_flags - Flags for Intel VT-d
> + *                                           stage-1 cache invalidation
> + * @IOMMU_VTD_QI_FLAGS_LEAF: The LEAF flag indicates whether only the
> + *                           leaf PTE caching needs to be invalidated
> + *                           and other paging structure caches can be
> + *                           preserved.
> + */
> +enum iommu_hwpt_vtd_s1_invalidate_flags {
> +	IOMMU_VTD_QI_FLAGS_LEAF = 1 << 0,
> +};

QI is iommu driver internal term.

let's use IOMMU_VTD_INV_FLAGS_LEAF here.

> +
> +/**
> + * struct iommu_hwpt_vtd_s1_invalidate - Intel VT-d cache invalidation
> + *                                       (IOMMU_HWPT_TYPE_VTD_S1)
> + * @addr: The start address of the addresses to be invalidated.
> + * @npages: Number of contiguous 4K pages to be invalidated.
> + * @flags: Combination of enum iommu_hwpt_vtd_s1_invalidate_flags
> + * @__reserved: Must be 0
> + *
> + * The Intel VT-d specific invalidation data for user-managed stage-1 cache
> + * invalidation under nested translation. Userspace uses this structure to

s/under/in/

> + * tell host about the impacted caches after modifying the stage-1 page
> table.

"to tell the impacted cache scope..."

> + *
> + * Invalidating all the caches related to the page table by setting @addr
> + * to be 0 and @npages to be __aligned_u64(-1).

This should also call out that device TLB is also invalidated by this request
if ATS is enabled on the device.

Re: [PATCH v5 07/11] iommufd: Add data structure for Intel VT-d stage-1 cache invalidation

Posted by Baolu Lu 1 year, 11 months ago

On 2023/9/21 15:54, Yi Liu wrote:
> This adds the data structure for flushing iotlb for the nested domain
> allocated with IOMMU_HWPT_TYPE_VTD_S1 type.
> 
> This only supports invalidating IOTLB, but no for device-TLB as device-TLB
> invalidation will be covered automatically in the IOTLB invalidation if the
> underlying IOMMU driver has enabled ATS for the affected device.
> 
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> ---
>   include/uapi/linux/iommufd.h | 34 ++++++++++++++++++++++++++++++++++
>   1 file changed, 34 insertions(+)
> 
> diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
> index 18a502e206c3..3050efbceb57 100644
> --- a/include/uapi/linux/iommufd.h
> +++ b/include/uapi/linux/iommufd.h
> @@ -510,6 +510,40 @@ struct iommu_hw_info {
>   };
>   #define IOMMU_GET_HW_INFO _IO(IOMMUFD_TYPE, IOMMUFD_CMD_GET_HW_INFO)
>   
> +/**
> + * enum iommu_hwpt_vtd_s1_invalidate_flags - Flags for Intel VT-d
> + *                                           stage-1 cache invalidation
> + * @IOMMU_VTD_QI_FLAGS_LEAF: The LEAF flag indicates whether only the
> + *                           leaf PTE caching needs to be invalidated
> + *                           and other paging structure caches can be
> + *                           preserved.
> + */
> +enum iommu_hwpt_vtd_s1_invalidate_flags {
> +	IOMMU_VTD_QI_FLAGS_LEAF = 1 << 0,
> +};
> +
> +/**
> + * struct iommu_hwpt_vtd_s1_invalidate - Intel VT-d cache invalidation
> + *                                       (IOMMU_HWPT_TYPE_VTD_S1)
> + * @addr: The start address of the addresses to be invalidated.

Is there an alignment requirement for @addr? If so, is 4K alignment
sufficient? Perhaps we need to document it here so that user space can
calculate the @addr correctly.

> + * @npages: Number of contiguous 4K pages to be invalidated.
> + * @flags: Combination of enum iommu_hwpt_vtd_s1_invalidate_flags
> + * @__reserved: Must be 0
> + *
> + * The Intel VT-d specific invalidation data for user-managed stage-1 cache
> + * invalidation under nested translation. Userspace uses this structure to
> + * tell host about the impacted caches after modifying the stage-1 page table.
> + *
> + * Invalidating all the caches related to the page table by setting @addr
> + * to be 0 and @npages to be __aligned_u64(-1).
> + */
> +struct iommu_hwpt_vtd_s1_invalidate {
> +	__aligned_u64 addr;
> +	__aligned_u64 npages;
> +	__u32 flags;
> +	__u32 __reserved;
> +};
> +
>   /**
>    * struct iommu_hwpt_invalidate - ioctl(IOMMU_HWPT_INVALIDATE)
>    * @size: sizeof(struct iommu_hwpt_invalidate)

Best regards,
baolu

Re: [PATCH v5 07/11] iommufd: Add data structure for Intel VT-d stage-1 cache invalidation

Posted by Yi Liu 1 year, 11 months ago

On 2023/9/21 21:33, Baolu Lu wrote:
> On 2023/9/21 15:54, Yi Liu wrote:
>> This adds the data structure for flushing iotlb for the nested domain
>> allocated with IOMMU_HWPT_TYPE_VTD_S1 type.
>>
>> This only supports invalidating IOTLB, but no for device-TLB as device-TLB
>> invalidation will be covered automatically in the IOTLB invalidation if the
>> underlying IOMMU driver has enabled ATS for the affected device.
>>
>> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
>> ---
>>   include/uapi/linux/iommufd.h | 34 ++++++++++++++++++++++++++++++++++
>>   1 file changed, 34 insertions(+)
>>
>> diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
>> index 18a502e206c3..3050efbceb57 100644
>> --- a/include/uapi/linux/iommufd.h
>> +++ b/include/uapi/linux/iommufd.h
>> @@ -510,6 +510,40 @@ struct iommu_hw_info {
>>   };
>>   #define IOMMU_GET_HW_INFO _IO(IOMMUFD_TYPE, IOMMUFD_CMD_GET_HW_INFO)
>> +/**
>> + * enum iommu_hwpt_vtd_s1_invalidate_flags - Flags for Intel VT-d
>> + *                                           stage-1 cache invalidation
>> + * @IOMMU_VTD_QI_FLAGS_LEAF: The LEAF flag indicates whether only the
>> + *                           leaf PTE caching needs to be invalidated
>> + *                           and other paging structure caches can be
>> + *                           preserved.
>> + */
>> +enum iommu_hwpt_vtd_s1_invalidate_flags {
>> +    IOMMU_VTD_QI_FLAGS_LEAF = 1 << 0,
>> +};
>> +
>> +/**
>> + * struct iommu_hwpt_vtd_s1_invalidate - Intel VT-d cache invalidation
>> + *                                       (IOMMU_HWPT_TYPE_VTD_S1)
>> + * @addr: The start address of the addresses to be invalidated.
> 
> Is there an alignment requirement for @addr? If so, is 4K alignment
> sufficient? Perhaps we need to document it here so that user space can
> calculate the @addr correctly.

yes, it should be aligned. let's document it in the kdoc.

> 
>> + * @npages: Number of contiguous 4K pages to be invalidated.
>> + * @flags: Combination of enum iommu_hwpt_vtd_s1_invalidate_flags
>> + * @__reserved: Must be 0
>> + *
>> + * The Intel VT-d specific invalidation data for user-managed stage-1 cache
>> + * invalidation under nested translation. Userspace uses this structure to
>> + * tell host about the impacted caches after modifying the stage-1 page 
>> table.
>> + *
>> + * Invalidating all the caches related to the page table by setting @addr
>> + * to be 0 and @npages to be __aligned_u64(-1).
>> + */
>> +struct iommu_hwpt_vtd_s1_invalidate {
>> +    __aligned_u64 addr;
>> +    __aligned_u64 npages;
>> +    __u32 flags;
>> +    __u32 __reserved;
>> +};
>> +
>>   /**
>>    * struct iommu_hwpt_invalidate - ioctl(IOMMU_HWPT_INVALIDATE)
>>    * @size: sizeof(struct iommu_hwpt_invalidate)
> 
> Best regards,
> baolu

-- 
Regards,
Yi Liu