Re: [PATCH] iommu/virtio: Update to most recent specification

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Jul 22, 2019 at 03:40:07PM +0100, Jean-Philippe Brucker wrote:
> Following specification review a few things were changed in v8 of the
> virtio-iommu series [1], but have been omitted when merging the base
> driver. Add them now:
> 
> * Remove the EXEC flag.
> * Add feature bit for the MMIO flag.
> * Change domain_bits to domain_range.
> * Add NOMEM status flag.
> 
> [1] https://lore.kernel.org/linux-iommu/20190530170929.19366-1-jean-philippe.brucker@arm.com/
> 
> Fixes: edcd69ab9a32 ("iommu: Add virtio-iommu driver")
> Reported-by: Eric Auger <eric.auger@redhat.com>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>

I'm merging this for this release, unless someone objects.

> ---
>  drivers/iommu/virtio-iommu.c      | 40 ++++++++++++++++++++++---------
>  include/uapi/linux/virtio_iommu.h | 32 ++++++++++++++-----------
>  2 files changed, 47 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
> index 433f4d2ee956..80a740df0737 100644
> --- a/drivers/iommu/virtio-iommu.c
> +++ b/drivers/iommu/virtio-iommu.c
> @@ -2,7 +2,7 @@
>  /*
>   * Virtio driver for the paravirtualized IOMMU
>   *
> - * Copyright (C) 2018 Arm Limited
> + * Copyright (C) 2019 Arm Limited
>   */
>  
>  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> @@ -47,7 +47,10 @@ struct viommu_dev {
>  	/* Device configuration */
>  	struct iommu_domain_geometry	geometry;
>  	u64				pgsize_bitmap;
> -	u8				domain_bits;
> +	u32				first_domain;
> +	u32				last_domain;
> +	/* Supported MAP flags */
> +	u32				map_flags;
>  	u32				probe_size;
>  };
>  
> @@ -62,6 +65,7 @@ struct viommu_domain {
>  	struct viommu_dev		*viommu;
>  	struct mutex			mutex; /* protects viommu pointer */
>  	unsigned int			id;
> +	u32				map_flags;
>  
>  	spinlock_t			mappings_lock;
>  	struct rb_root_cached		mappings;
> @@ -113,6 +117,8 @@ static int viommu_get_req_errno(void *buf, size_t len)
>  		return -ENOENT;
>  	case VIRTIO_IOMMU_S_FAULT:
>  		return -EFAULT;
> +	case VIRTIO_IOMMU_S_NOMEM:
> +		return -ENOMEM;
>  	case VIRTIO_IOMMU_S_IOERR:
>  	case VIRTIO_IOMMU_S_DEVERR:
>  	default:
> @@ -607,15 +613,15 @@ static int viommu_domain_finalise(struct viommu_dev *viommu,
>  {
>  	int ret;
>  	struct viommu_domain *vdomain = to_viommu_domain(domain);
> -	unsigned int max_domain = viommu->domain_bits > 31 ? ~0 :
> -				  (1U << viommu->domain_bits) - 1;
>  
>  	vdomain->viommu		= viommu;
> +	vdomain->map_flags	= viommu->map_flags;
>  
>  	domain->pgsize_bitmap	= viommu->pgsize_bitmap;
>  	domain->geometry	= viommu->geometry;
>  
> -	ret = ida_alloc_max(&viommu->domain_ids, max_domain, GFP_KERNEL);
> +	ret = ida_alloc_range(&viommu->domain_ids, viommu->first_domain,
> +			      viommu->last_domain, GFP_KERNEL);
>  	if (ret >= 0)
>  		vdomain->id = (unsigned int)ret;
>  
> @@ -710,7 +716,7 @@ static int viommu_map(struct iommu_domain *domain, unsigned long iova,
>  		      phys_addr_t paddr, size_t size, int prot)
>  {
>  	int ret;
> -	int flags;
> +	u32 flags;
>  	struct virtio_iommu_req_map map;
>  	struct viommu_domain *vdomain = to_viommu_domain(domain);
>  
> @@ -718,6 +724,9 @@ static int viommu_map(struct iommu_domain *domain, unsigned long iova,
>  		(prot & IOMMU_WRITE ? VIRTIO_IOMMU_MAP_F_WRITE : 0) |
>  		(prot & IOMMU_MMIO ? VIRTIO_IOMMU_MAP_F_MMIO : 0);
>  
> +	if (flags & ~vdomain->map_flags)
> +		return -EINVAL;
> +
>  	ret = viommu_add_mapping(vdomain, iova, paddr, size, flags);
>  	if (ret)
>  		return ret;
> @@ -1027,7 +1036,8 @@ static int viommu_probe(struct virtio_device *vdev)
>  		goto err_free_vqs;
>  	}
>  
> -	viommu->domain_bits = 32;
> +	viommu->map_flags = VIRTIO_IOMMU_MAP_F_READ | VIRTIO_IOMMU_MAP_F_WRITE;
> +	viommu->last_domain = ~0U;
>  
>  	/* Optional features */
>  	virtio_cread_feature(vdev, VIRTIO_IOMMU_F_INPUT_RANGE,
> @@ -1038,9 +1048,13 @@ static int viommu_probe(struct virtio_device *vdev)
>  			     struct virtio_iommu_config, input_range.end,
>  			     &input_end);
>  
> -	virtio_cread_feature(vdev, VIRTIO_IOMMU_F_DOMAIN_BITS,
> -			     struct virtio_iommu_config, domain_bits,
> -			     &viommu->domain_bits);
> +	virtio_cread_feature(vdev, VIRTIO_IOMMU_F_DOMAIN_RANGE,
> +			     struct virtio_iommu_config, domain_range.start,
> +			     &viommu->first_domain);
> +
> +	virtio_cread_feature(vdev, VIRTIO_IOMMU_F_DOMAIN_RANGE,
> +			     struct virtio_iommu_config, domain_range.end,
> +			     &viommu->last_domain);
>  
>  	virtio_cread_feature(vdev, VIRTIO_IOMMU_F_PROBE,
>  			     struct virtio_iommu_config, probe_size,
> @@ -1052,6 +1066,9 @@ static int viommu_probe(struct virtio_device *vdev)
>  		.force_aperture	= true,
>  	};
>  
> +	if (virtio_has_feature(vdev, VIRTIO_IOMMU_F_MMIO))
> +		viommu->map_flags |= VIRTIO_IOMMU_MAP_F_MMIO;
> +
>  	viommu_ops.pgsize_bitmap = viommu->pgsize_bitmap;
>  
>  	virtio_device_ready(vdev);
> @@ -1130,9 +1147,10 @@ static void viommu_config_changed(struct virtio_device *vdev)
>  
>  static unsigned int features[] = {
>  	VIRTIO_IOMMU_F_MAP_UNMAP,
> -	VIRTIO_IOMMU_F_DOMAIN_BITS,
>  	VIRTIO_IOMMU_F_INPUT_RANGE,
> +	VIRTIO_IOMMU_F_DOMAIN_RANGE,
>  	VIRTIO_IOMMU_F_PROBE,
> +	VIRTIO_IOMMU_F_MMIO,
>  };
>  
>  static struct virtio_device_id id_table[] = {
> diff --git a/include/uapi/linux/virtio_iommu.h b/include/uapi/linux/virtio_iommu.h
> index ba1b460c9944..237e36a280cb 100644
> --- a/include/uapi/linux/virtio_iommu.h
> +++ b/include/uapi/linux/virtio_iommu.h
> @@ -1,8 +1,8 @@
>  /* SPDX-License-Identifier: BSD-3-Clause */
>  /*
> - * Virtio-iommu definition v0.9
> + * Virtio-iommu definition v0.12
>   *
> - * Copyright (C) 2018 Arm Ltd.
> + * Copyright (C) 2019 Arm Ltd.
>   */
>  #ifndef _UAPI_LINUX_VIRTIO_IOMMU_H
>  #define _UAPI_LINUX_VIRTIO_IOMMU_H
> @@ -11,26 +11,31 @@
>  
>  /* Feature bits */
>  #define VIRTIO_IOMMU_F_INPUT_RANGE		0
> -#define VIRTIO_IOMMU_F_DOMAIN_BITS		1
> +#define VIRTIO_IOMMU_F_DOMAIN_RANGE		1
>  #define VIRTIO_IOMMU_F_MAP_UNMAP		2
>  #define VIRTIO_IOMMU_F_BYPASS			3
>  #define VIRTIO_IOMMU_F_PROBE			4
> +#define VIRTIO_IOMMU_F_MMIO			5
>  
> -struct virtio_iommu_range {
> -	__u64					start;
> -	__u64					end;
> +struct virtio_iommu_range_64 {
> +	__le64					start;
> +	__le64					end;
> +};
> +
> +struct virtio_iommu_range_32 {
> +	__le32					start;
> +	__le32					end;
>  };
>  
>  struct virtio_iommu_config {
>  	/* Supported page sizes */
> -	__u64					page_size_mask;
> +	__le64					page_size_mask;
>  	/* Supported IOVA range */
> -	struct virtio_iommu_range		input_range;
> +	struct virtio_iommu_range_64		input_range;
>  	/* Max domain ID size */
> -	__u8					domain_bits;
> -	__u8					padding[3];
> +	struct virtio_iommu_range_32		domain_range;
>  	/* Probe buffer size */
> -	__u32					probe_size;
> +	__le32					probe_size;
>  };
>  
>  /* Request types */
> @@ -49,6 +54,7 @@ struct virtio_iommu_config {
>  #define VIRTIO_IOMMU_S_RANGE			0x05
>  #define VIRTIO_IOMMU_S_NOENT			0x06
>  #define VIRTIO_IOMMU_S_FAULT			0x07
> +#define VIRTIO_IOMMU_S_NOMEM			0x08
>  
>  struct virtio_iommu_req_head {
>  	__u8					type;
> @@ -78,12 +84,10 @@ struct virtio_iommu_req_detach {
>  
>  #define VIRTIO_IOMMU_MAP_F_READ			(1 << 0)
>  #define VIRTIO_IOMMU_MAP_F_WRITE		(1 << 1)
> -#define VIRTIO_IOMMU_MAP_F_EXEC			(1 << 2)
> -#define VIRTIO_IOMMU_MAP_F_MMIO			(1 << 3)
> +#define VIRTIO_IOMMU_MAP_F_MMIO			(1 << 2)
>  
>  #define VIRTIO_IOMMU_MAP_F_MASK			(VIRTIO_IOMMU_MAP_F_READ |	\
>  						 VIRTIO_IOMMU_MAP_F_WRITE |	\
> -						 VIRTIO_IOMMU_MAP_F_EXEC |	\
>  						 VIRTIO_IOMMU_MAP_F_MMIO)
>  
>  struct virtio_iommu_req_map {
> -- 
> 2.22.0
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