From: Vasant Hegde <vasant.hegde@amd.com>
To: iommu@lists.linux.dev, joro@8bytes.org
Cc: robin.murphy@arm.com, will@kernel.org, suravee.suthikulpanit@amd.com
Subject: Re: [PATCH 1/3] iommu: Attach device group to old domain in error path
Date: Wed, 1 Feb 2023 10:49:54 +0530 [thread overview]
Message-ID: <4750852f-53ea-719a-cc03-e2da34e5782d@amd.com> (raw)
In-Reply-To: <20230113135956.5788-1-vasant.hegde@amd.com>
Hi Joerg,
Did you get chance to look into this series?
-Vasant
On 1/13/2023 7:29 PM, Vasant Hegde wrote:
> iommu_attach_group() attaches all devices in a group to domain and then
> sets group domain (group->domain). Current code (__iommu_attach_group())
> does not handle error path. This creates problem as devices to domain
> attachment is in inconsistent state.
>
> To recover from this situation, we need force attaching all devices back
> to the old domain. This patch introduces `force` parameter to
> __iommu_group_set_domain() so that we can attach devices back to old
> domain.
>
> Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
> ---
> drivers/iommu/iommu.c | 24 +++++++++++++++++-------
> 1 file changed, 17 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index de91dd88705b..e58683cd3bf7 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -95,7 +95,8 @@ static int __iommu_attach_device(struct iommu_domain *domain,
> static int __iommu_attach_group(struct iommu_domain *domain,
> struct iommu_group *group);
> static int __iommu_group_set_domain(struct iommu_group *group,
> - struct iommu_domain *new_domain);
> + struct iommu_domain *new_domain,
> + bool force);
> static int iommu_create_device_direct_mappings(struct iommu_group *group,
> struct device *dev);
> static struct iommu_group *iommu_group_get_for_dev(struct device *dev);
> @@ -1974,7 +1975,7 @@ static void __iommu_group_set_core_domain(struct iommu_group *group)
> else
> new_domain = group->default_domain;
>
> - ret = __iommu_group_set_domain(group, new_domain);
> + ret = __iommu_group_set_domain(group, new_domain, false);
> WARN(ret, "iommu driver failed to attach the default/blocking domain");
> }
>
> @@ -2124,8 +2125,16 @@ static int __iommu_attach_group(struct iommu_domain *domain,
>
> ret = __iommu_group_for_each_dev(group, domain,
> iommu_group_do_attach_device);
> - if (ret == 0)
> + if (ret == 0) {
> group->domain = domain;
> + } else {
> + /*
> + * To recover from the case when certain device within the
> + * group fails to attach to the new domain, we need force
> + * attaching all devices back to the old domain.
> + */
> + __iommu_group_set_domain(group, group->domain, true);
> + }
>
> return ret;
> }
> @@ -2164,11 +2173,12 @@ static int iommu_group_do_detach_device(struct device *dev, void *data)
> }
>
> static int __iommu_group_set_domain(struct iommu_group *group,
> - struct iommu_domain *new_domain)
> + struct iommu_domain *new_domain,
> + bool force)
> {
> int ret;
>
> - if (group->domain == new_domain)
> + if (!force && group->domain == new_domain)
> return 0;
>
> /*
> @@ -3135,7 +3145,7 @@ static int __iommu_take_dma_ownership(struct iommu_group *group, void *owner)
> ret = __iommu_group_alloc_blocking_domain(group);
> if (ret)
> return ret;
> - ret = __iommu_group_set_domain(group, group->blocking_domain);
> + ret = __iommu_group_set_domain(group, group->blocking_domain, false);
> if (ret)
> return ret;
>
> @@ -3222,7 +3232,7 @@ static void __iommu_release_dma_ownership(struct iommu_group *group)
>
> group->owner_cnt = 0;
> group->owner = NULL;
> - ret = __iommu_group_set_domain(group, group->default_domain);
> + ret = __iommu_group_set_domain(group, group->default_domain, false);
> WARN(ret, "iommu driver failed to attach the default domain");
> }
>
prev parent reply other threads:[~2023-02-01 5:20 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-13 13:59 [PATCH 1/3] iommu: Attach device group to old domain in error path Vasant Hegde
2023-01-13 13:59 ` [PATCH 2/3] iommu/amd: Skip attach device domain is same as new domain Vasant Hegde
2023-01-13 13:59 ` [PATCH 3/3] iommu/amd: Call BUG_ON in page fault hanlder path if domain is NULL Vasant Hegde
2023-01-13 16:15 ` Robin Murphy
2023-01-17 4:56 ` Vasant Hegde
2023-02-03 9:36 ` Joerg Roedel
2023-02-03 10:40 ` Vasant Hegde
2023-02-03 11:12 ` Joerg Roedel
2023-02-03 16:52 ` Vasant Hegde
2023-02-01 5:19 ` Vasant Hegde [this message]
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