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

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Message-ID: <20190329181846.jjo2wijxkibfs35m@cantor>
Date:   Fri, 29 Mar 2019 11:18:46 -0700
From:   Jerry Snitselaar <jsnitsel@...hat.com>
To:     Joerg Roedel <joro@...tes.org>
Cc:     iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        Gary R Hook <ghook@....com>, Joerg Roedel <jroedel@...e.de>
Subject: Re: [PATCH v2] iommu/amd: Reserve exclusion range in iova-domain

On Fri Mar 29 19, 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.
>
>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
>-- 
>2.16.4
>

Reviewed-by: Jerry Snitselaar <jsnitsel@...hat.com>