From: Lu Baolu <baolu.lu@linux.intel.com>
To: Robin Murphy <robin.murphy@arm.com>, joro@8bytes.org, will@kernel.org
Cc: baolu.lu@linux.intel.com, iommu@lists.linux-foundation.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, suravee.suthikulpanit@amd.com,
john.garry@huawei.com, dianders@chromium.org
Subject: Re: [PATCH v2 22/24] iommu: Allow enabling non-strict mode dynamically
Date: Fri, 30 Jul 2021 14:11:44 +0800 [thread overview]
Message-ID: <94645a8e-471d-2daa-d385-95a337025721@linux.intel.com> (raw)
In-Reply-To: <de75b36b3b31cd328de3811c0725f3d0af448abc.1627468310.git.robin.murphy@arm.com>
On 7/28/21 11:58 PM, Robin Murphy wrote:
> Allocating and enabling a flush queue is in fact something we can
> reasonably do while a DMA domain is active, without having to rebuild it
> from scratch. Thus we can allow a strict -> non-strict transition from
> sysfs without requiring to unbind the device's driver, which is of
> particular interest to users who want to make selective relaxations to
> critical devices like the one serving their root filesystem.
>
> Disabling and draining a queue also seems technically possible to
> achieve without rebuilding the whole domain, but would certainly be more
> involved. Furthermore there's not such a clear use-case for tightening
> up security *after* the device may already have done whatever it is that
> you don't trust it not to do, so we only consider the relaxation case.
>
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> ---
> drivers/iommu/iommu.c | 16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 25c1adc1ec67..be399d630953 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -3200,6 +3200,13 @@ static int iommu_change_dev_def_domain(struct iommu_group *group,
> goto out;
> }
>
> + /* We can bring up a flush queue without tearing down the domain */
> + if (type == IOMMU_DOMAIN_DMA_FQ && prev_dom->type == IOMMU_DOMAIN_DMA) {
> + prev_dom->type = IOMMU_DOMAIN_DMA_FQ;
> + ret = iommu_dma_init_fq(prev_dom);
> + goto out;
> + }
> +
> /* Sets group->default_domain to the newly allocated domain */
> ret = iommu_group_alloc_default_domain(dev->bus, group, type);
> if (ret)
> @@ -3240,9 +3247,9 @@ static int iommu_change_dev_def_domain(struct iommu_group *group,
> }
>
> /*
> - * Changing the default domain through sysfs requires the users to ubind the
> - * drivers from the devices in the iommu group. Return failure if this doesn't
> - * meet.
> + * Changing the default domain through sysfs requires the users to unbind the
> + * drivers from the devices in the iommu group, except for a DMA -> DMA-FQ
> + * transition. Return failure if this isn't met.
> *
> * We need to consider the race between this and the device release path.
> * device_lock(dev) is used here to guarantee that the device release path
> @@ -3318,7 +3325,8 @@ static ssize_t iommu_group_store_type(struct iommu_group *group,
>
> /* Check if the device in the group still has a driver bound to it */
> device_lock(dev);
> - if (device_is_bound(dev)) {
> + if (device_is_bound(dev) && !(req_type == IOMMU_DOMAIN_DMA_FQ &&
> + group->default_domain->type == IOMMU_DOMAIN_DMA)) {
> pr_err_ratelimited("Device is still bound to driver\n");
> ret = -EBUSY;
> goto out;
>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Best regards,
baolu
next prev parent reply other threads:[~2021-07-30 6:14 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-28 15:58 [PATCH v2 00/24] iommu: Refactor DMA domain strictness Robin Murphy
2021-07-28 15:58 ` [PATCH v2 01/24] iommu: Pull IOVA cookie management into the core Robin Murphy
2021-07-30 6:06 ` Lu Baolu
2021-07-30 9:32 ` Jean-Philippe Brucker
2021-07-28 15:58 ` [PATCH v2 02/24] iommu/amd: Drop IOVA cookie management Robin Murphy
2021-07-28 15:58 ` [PATCH v2 03/24] iommu/arm-smmu: " Robin Murphy
2021-07-28 15:58 ` [PATCH v2 04/24] iommu/vt-d: " Robin Murphy
2021-07-30 6:07 ` Lu Baolu
2021-07-28 15:58 ` [PATCH v2 05/24] iommu/exynos: " Robin Murphy
2021-07-28 15:58 ` [PATCH v2 06/24] iommu/ipmmu-vmsa: " Robin Murphy
2021-07-28 15:58 ` [PATCH v2 07/24] iommu/mtk: " Robin Murphy
2021-07-28 15:58 ` [PATCH v2 08/24] iommu/rockchip: " Robin Murphy
2021-07-28 15:58 ` [PATCH v2 09/24] iommu/sprd: " Robin Murphy
2021-07-28 15:58 ` [PATCH v2 10/24] iommu/sun50i: " Robin Murphy
2021-07-28 15:58 ` [PATCH v2 11/24] iommu/virtio: " Robin Murphy
2021-07-30 9:20 ` Jean-Philippe Brucker
2021-07-28 15:58 ` [PATCH v2 12/24] iommu/dma: Unexport " Robin Murphy
2021-07-30 6:07 ` Lu Baolu
2021-07-30 9:21 ` Jean-Philippe Brucker
2021-07-28 15:58 ` [PATCH v2 13/24] iommu/dma: Remove redundant "!dev" checks Robin Murphy
2021-07-30 6:08 ` Lu Baolu
2021-07-28 15:58 ` [PATCH v2 14/24] iommu: Introduce explicit type for non-strict DMA domains Robin Murphy
2021-07-30 6:08 ` Lu Baolu
2021-07-30 9:23 ` Jean-Philippe Brucker
2021-07-28 15:58 ` [PATCH v2 15/24] iommu/amd: Prepare for multiple DMA domain types Robin Murphy
2021-07-28 15:58 ` [PATCH v2 16/24] iommu/arm-smmu: " Robin Murphy
2021-07-28 15:58 ` [PATCH v2 17/24] iommu/vt-d: " Robin Murphy
2021-07-30 6:09 ` Lu Baolu
2021-07-28 15:58 ` [PATCH v2 18/24] iommu: Express DMA strictness via the domain type Robin Murphy
2021-07-29 7:13 ` Lu Baolu
2021-07-29 9:36 ` Robin Murphy
2021-07-29 12:42 ` Lu Baolu
2021-07-30 6:09 ` Lu Baolu
2021-07-28 15:58 ` [PATCH v2 19/24] iommu: Expose DMA domain strictness via sysfs Robin Murphy
2021-07-30 6:10 ` Lu Baolu
2021-07-30 9:28 ` Jean-Philippe Brucker
2021-07-30 10:20 ` John Garry
2021-07-28 15:58 ` [PATCH v2 20/24] iommu: Merge strictness and domain type configs Robin Murphy
2021-07-30 6:10 ` Lu Baolu
2021-07-30 9:29 ` Jean-Philippe Brucker
2021-07-30 9:33 ` John Garry
2021-07-28 15:58 ` [PATCH v2 21/24] iommu/dma: Factor out flush queue init Robin Murphy
2021-07-30 6:11 ` Lu Baolu
2021-07-30 9:20 ` John Garry
2021-07-28 15:58 ` [PATCH v2 22/24] iommu: Allow enabling non-strict mode dynamically Robin Murphy
2021-07-30 6:11 ` Lu Baolu [this message]
2021-07-30 9:24 ` John Garry
2021-07-28 15:58 ` [PATCH v2 23/24] iommu/arm-smmu: Allow non-strict in pgtable_quirks interface Robin Murphy
2021-08-02 13:04 ` Will Deacon
2021-08-02 14:15 ` Robin Murphy
2021-08-03 10:36 ` Will Deacon
2021-08-03 12:13 ` Robin Murphy
2021-08-03 12:35 ` Will Deacon
2021-07-28 15:58 ` [PATCH v2 24/24] iommu: Only log strictness for DMA domains Robin Murphy
2021-07-29 9:04 ` John Garry
2021-07-30 6:12 ` Lu Baolu
2021-07-29 2:55 ` [PATCH v2 00/24] iommu: Refactor DMA domain strictness chenxiang (M)
2021-07-29 10:59 ` Robin Murphy
2021-07-30 1:21 ` chenxiang (M)
2021-07-29 15:04 ` Heiko Stübner
2021-07-29 15:43 ` Robin Murphy
2021-07-29 15:53 ` Heiko Stübner
2021-07-29 16:29 ` Robin Murphy
2021-07-29 22:33 ` Doug Anderson
2021-07-30 0:06 ` Doug Anderson
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