Re: [PATCH RFC v1 06/15] iommu/virtio: Add headers for table format probing - Jean-Philippe Brucker

From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: Vivek Gautam <vivek.gautam@arm.com>
Cc: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	iommu@lists.linux-foundation.org,
	virtualization@lists.linux-foundation.org, joro@8bytes.org,
	will.deacon@arm.com, mst@redhat.com, robin.murphy@arm.com,
	eric.auger@redhat.com, alex.williamson@redhat.com,
	kevin.tian@intel.com, jacob.jun.pan@linux.intel.com,
	yi.l.liu@intel.com, lorenzo.pieralisi@arm.com,
	shameerali.kolothum.thodi@huawei.com
Subject: Re: [PATCH RFC v1 06/15] iommu/virtio: Add headers for table format probing
Date: Wed, 3 Mar 2021 18:17:58 +0100	[thread overview]
Message-ID: <YD/ExjIwG/as52CI@myrica> (raw)
In-Reply-To: <20210115121342.15093-7-vivek.gautam@arm.com>

On Fri, Jan 15, 2021 at 05:43:33PM +0530, Vivek Gautam wrote:
> From: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
> 
> Add required UAPI defines for probing table format for underlying
> iommu hardware. The device may provide information about hardware
> tables and additional capabilities for each device.
> This allows guest to correctly fabricate stage-1 page tables.
> 
> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
> [Vivek: Use a single "struct virtio_iommu_probe_table_format" rather
>         than separate structures for page table and pasid table format.

Makes sense. I've integrated that into the spec draft, added more precise
documentation and modified some of the definitions.

The current draft is here:
https://jpbrucker.net/virtio-iommu/spec/virtio-iommu-v0.13.pdf
Posted on the list here
https://lists.oasis-open.org/archives/virtio-dev/202102/msg00012.html

> 	Also update commit message.]
> Signed-off-by: Vivek Gautam <vivek.gautam@arm.com>
> Cc: Joerg Roedel <joro@8bytes.org>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Robin Murphy <robin.murphy@arm.com>
> Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
> Cc: Eric Auger <eric.auger@redhat.com>
> Cc: Alex Williamson <alex.williamson@redhat.com>
> Cc: Kevin Tian <kevin.tian@intel.com>
> Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Cc: Liu Yi L <yi.l.liu@intel.com>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Cc: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
> ---
>  include/uapi/linux/virtio_iommu.h | 44 ++++++++++++++++++++++++++++++-
>  1 file changed, 43 insertions(+), 1 deletion(-)
> 
> diff --git a/include/uapi/linux/virtio_iommu.h b/include/uapi/linux/virtio_iommu.h
> index 237e36a280cb..43821e33e7af 100644
> --- a/include/uapi/linux/virtio_iommu.h
> +++ b/include/uapi/linux/virtio_iommu.h
> @@ -2,7 +2,7 @@
>  /*
>   * Virtio-iommu definition v0.12
>   *
> - * Copyright (C) 2019 Arm Ltd.
> + * Copyright (C) 2019-2021 Arm Ltd.

Not strictly necessary. But if you're modifying this comment please also
remove the "v0.12" above

>   */
>  #ifndef _UAPI_LINUX_VIRTIO_IOMMU_H
>  #define _UAPI_LINUX_VIRTIO_IOMMU_H
> @@ -111,6 +111,12 @@ struct virtio_iommu_req_unmap {
>  
>  #define VIRTIO_IOMMU_PROBE_T_NONE		0
>  #define VIRTIO_IOMMU_PROBE_T_RESV_MEM		1
> +#define VIRTIO_IOMMU_PROBE_T_PAGE_SIZE_MASK	2
> +#define VIRTIO_IOMMU_PROBE_T_INPUT_RANGE	3
> +#define VIRTIO_IOMMU_PROBE_T_OUTPUT_SIZE	4
> +#define VIRTIO_IOMMU_PROBE_T_PASID_SIZE		5
> +#define VIRTIO_IOMMU_PROBE_T_PAGE_TABLE_FMT	6
> +#define VIRTIO_IOMMU_PROBE_T_PASID_TABLE_FMT	7

Since there is a single struct we can have a single
VIRTIO_IOMMU_PROBE_T_TABLE_FORMAT.

>  
>  #define VIRTIO_IOMMU_PROBE_T_MASK		0xfff
>  
> @@ -130,6 +136,42 @@ struct virtio_iommu_probe_resv_mem {
>  	__le64					end;
>  };
>  
> +struct virtio_iommu_probe_page_size_mask {
> +	struct virtio_iommu_probe_property	head;
> +	__u8					reserved[4];
> +	__le64					mask;
> +};
> +
> +struct virtio_iommu_probe_input_range {
> +	struct virtio_iommu_probe_property	head;
> +	__u8					reserved[4];
> +	__le64					start;
> +	__le64					end;
> +};
> +
> +struct virtio_iommu_probe_output_size {
> +	struct virtio_iommu_probe_property	head;
> +	__u8					bits;
> +	__u8					reserved[3];
> +};
> +
> +struct virtio_iommu_probe_pasid_size {
> +	struct virtio_iommu_probe_property	head;
> +	__u8					bits;
> +	__u8					reserved[3];
> +};
> +
> +/* Arm LPAE page table format */
> +#define VIRTIO_IOMMU_FOMRAT_PGTF_ARM_LPAE	1

s/FOMRAT/FORMAT

> +/* Arm smmu-v3 type PASID table format */
> +#define VIRTIO_IOMMU_FORMAT_PSTF_ARM_SMMU_V3	2

These should be with the Arm-specific definitions patches 11 and 14

Thanks,
Jean

> +
> +struct virtio_iommu_probe_table_format {
> +	struct virtio_iommu_probe_property	head;
> +	__le16					format;
> +	__u8					reserved[2];
> +};
> +
>  struct virtio_iommu_req_probe {
>  	struct virtio_iommu_req_head		head;
>  	__le32					endpoint;
> -- 
> 2.17.1
> 

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