linux-kernel - Re: [PATCH v2] iommu/amd: Reserve exclusion range in iova-domain

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Date:   Fri, 29 Mar 2019 16:00:43 +0000
From:   Gary R Hook <ghook@....com>
To:     Joerg Roedel <joro@...tes.org>,
        "iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Joerg Roedel <jroedel@...e.de>
Subject: Re: [PATCH v2] iommu/amd: Reserve exclusion range in iova-domain

On 3/29/19 10:10 AM, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@...e.de>
> 
> If a device has an exclusion range specified in the IVRS
> table, this region needs to be reserved in the iova-domain
> of that device. This hasn't happened until now and can cause
> data corruption on data transfered with these devices.
> 
> Treat exclusion ranges as reserved regions in the iommu-core
> to fix the problem.

Reviewed-by: Gary R Hook <gary.hook@....com>

> 
> Fixes: be2a022c0dd0 ('x86, AMD IOMMU: add functions to parse IOMMU memory mapping requirements for devices')
> Signed-off-by: Joerg Roedel <jroedel@...e.de>
> ---
>   drivers/iommu/amd_iommu.c       | 9 ++++++---
>   drivers/iommu/amd_iommu_init.c  | 7 ++++---
>   drivers/iommu/amd_iommu_types.h | 2 ++
>   3 files changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> index 21cb088d6687..f7cdd2ab7f11 100644
> --- a/drivers/iommu/amd_iommu.c
> +++ b/drivers/iommu/amd_iommu.c
> @@ -3169,21 +3169,24 @@ static void amd_iommu_get_resv_regions(struct device *dev,
>   		return;
>   
>   	list_for_each_entry(entry, &amd_iommu_unity_map, list) {
> +		int type, prot = 0;
>   		size_t length;
> -		int prot = 0;
>   
>   		if (devid < entry->devid_start || devid > entry->devid_end)
>   			continue;
>   
> +		type   = IOMMU_RESV_DIRECT;
>   		length = entry->address_end - entry->address_start;
>   		if (entry->prot & IOMMU_PROT_IR)
>   			prot |= IOMMU_READ;
>   		if (entry->prot & IOMMU_PROT_IW)
>   			prot |= IOMMU_WRITE;
> +		if (entry->prot & IOMMU_UNITY_MAP_FLAG_EXCL_RANGE)
> +			/* Exclusion range */
> +			type = IOMMU_RESV_RESERVED;
>   
>   		region = iommu_alloc_resv_region(entry->address_start,
> -						 length, prot,
> -						 IOMMU_RESV_DIRECT);
> +						 length, prot, type);
>   		if (!region) {
>   			dev_err(dev, "Out of memory allocating dm-regions\n");
>   			return;
> diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
> index f773792d77fd..1b1378619fc9 100644
> --- a/drivers/iommu/amd_iommu_init.c
> +++ b/drivers/iommu/amd_iommu_init.c
> @@ -2013,6 +2013,9 @@ static int __init init_unity_map_range(struct ivmd_header *m)
>   	if (e == NULL)
>   		return -ENOMEM;
>   
> +	if (m->flags & IVMD_FLAG_EXCL_RANGE)
> +		init_exclusion_range(m);
> +
>   	switch (m->type) {
>   	default:
>   		kfree(e);
> @@ -2059,9 +2062,7 @@ static int __init init_memory_definitions(struct acpi_table_header *table)
>   
>   	while (p < end) {
>   		m = (struct ivmd_header *)p;
> -		if (m->flags & IVMD_FLAG_EXCL_RANGE)
> -			init_exclusion_range(m);
> -		else if (m->flags & IVMD_FLAG_UNITY_MAP)
> +		if (m->flags & (IVMD_FLAG_UNITY_MAP | IVMD_FLAG_EXCL_RANGE))
>   			init_unity_map_range(m);
>   
>   		p += m->length;
> diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
> index eae0741f72dc..87965e4d9647 100644
> --- a/drivers/iommu/amd_iommu_types.h
> +++ b/drivers/iommu/amd_iommu_types.h
> @@ -374,6 +374,8 @@
>   #define IOMMU_PROT_IR 0x01
>   #define IOMMU_PROT_IW 0x02
>   
> +#define IOMMU_UNITY_MAP_FLAG_EXCL_RANGE	(1 << 2)
> +
>   /* IOMMU capabilities */
>   #define IOMMU_CAP_IOTLB   24
>   #define IOMMU_CAP_NPCACHE 26
>