From: John Garry <john.garry@huawei.com>
To: <joro@8bytes.org>, <will@kernel.org>, <dwmw2@infradead.org>,
<baolu.lu@linux.intel.com>, <robin.murphy@arm.com>
Cc: <linux-kernel@vger.kernel.org>,
<iommu@lists.linux-foundation.org>, <linuxarm@huawei.com>,
<thunder.leizhen@huawei.com>, <chenxiang66@hisilicon.com>,
John Garry <john.garry@huawei.com>
Subject: [PATCH v10 1/3] iommu: Enhance IOMMU default DMA mode build options
Date: Thu, 3 Jun 2021 21:58:33 +0800 [thread overview]
Message-ID: <1622728715-209296-2-git-send-email-john.garry@huawei.com> (raw)
In-Reply-To: <1622728715-209296-1-git-send-email-john.garry@huawei.com>
From: Zhen Lei <thunder.leizhen@huawei.com>
First, add build options IOMMU_DEFAULT_{LAZY|STRICT}, so that we have the
opportunity to set {lazy|strict} mode as default at build time. Then put
the two config options in an choice, as they are mutually-exclusive.
[jpg: Make choice between strict and lazy only (and not passthrough)]
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: John Garry <john.garry@huawei.com>
---
drivers/iommu/Kconfig | 34 ++++++++++++++++++++++++++++++++++
drivers/iommu/iommu.c | 3 ++-
2 files changed, 36 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 1f111b399bca..12ef90256df8 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -90,6 +90,40 @@ config IOMMU_DEFAULT_PASSTHROUGH
If unsure, say N here.
+choice
+ prompt "IOMMU default DMA mode"
+ depends on IOMMU_API
+
+ default IOMMU_DEFAULT_STRICT
+ help
+ This option allows an IOMMU DMA mode to be chosen at build time, to
+ override the default DMA mode of each ARCH, removing the need to
+ pass in kernel parameters through command line. It is still possible
+ to provide ARCH-specific or common boot options to override this
+ option.
+
+ If unsure, keep the default.
+
+config IOMMU_DEFAULT_LAZY
+ bool "lazy"
+ help
+ Support lazy mode, where for every IOMMU DMA unmap operation, the
+ flush operation of IOTLB and the free operation of IOVA are deferred.
+ They are only guaranteed to be done before the related IOVA will be
+ reused.
+
+config IOMMU_DEFAULT_STRICT
+ bool "strict"
+ help
+ For every IOMMU DMA unmap operation, the flush operation of IOTLB and
+ the free operation of IOVA are guaranteed to be done in the unmap
+ function.
+
+ This mode is safer than the two above, but it maybe slower in some
+ high performace scenarios.
+
+endchoice
+
config OF_IOMMU
def_bool y
depends on OF && IOMMU_API
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 966426a96520..177b0dafc535 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -29,7 +29,8 @@ static struct kset *iommu_group_kset;
static DEFINE_IDA(iommu_group_ida);
static unsigned int iommu_def_domain_type __read_mostly;
-static bool iommu_dma_strict __read_mostly = true;
+static bool iommu_dma_strict __read_mostly =
+ IS_ENABLED(CONFIG_IOMMU_DEFAULT_STRICT);
static u32 iommu_cmd_line __read_mostly;
struct iommu_group {
--
2.26.2
next prev parent reply other threads:[~2021-06-03 14:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-03 13:58 [PATCH v10 0/3] Enhance IOMMU default DMA mode build options John Garry
2021-06-03 13:58 ` John Garry [this message]
2021-06-03 17:00 ` [PATCH v10 1/3] iommu: " Randy Dunlap
2021-06-03 17:04 ` John Garry
2021-06-04 2:54 ` Leizhen (ThunderTown)
2021-06-04 8:19 ` John Garry
2021-06-03 13:58 ` [PATCH v10 2/3] iommu/vt-d: Add support for " John Garry
2021-06-03 13:58 ` [PATCH v10 3/3] iommu/amd: " John Garry
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