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From: Kenneth Lee <nek.in.cn@gmail.com>
To: Jonathan Corbet <corbet@lwn.net>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	"David S . Miller" <davem@davemloft.net>,
	Joerg Roedel <joro@8bytes.org>,
	Alex Williamson <alex.williamson@redhat.com>,
	Kenneth Lee <liguozhu@hisilicon.com>,
	Hao Fang <fanghao11@huawei.com>,
	Zhou Wang <wangzhou1@hisilicon.com>,
	Zaibo Xu <xuzaibo@huawei.com>,
	Philippe Ombredanne <pombredanne@nexb.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-crypto@vger.kernel.org, iommu@lists.linux-foundation.org,
	kvm@vger.kernel.org, linux-accelerators@lists.ozlabs.org,
	Lu Baolu <baolu.lu@linux.intel.com>,
	Sanjay Kumar <sanjay.k.kumar@intel.com>
Cc: linuxarm@huawei.com
Subject: [RFC PATCH 2/7] iommu: Add share domain interface in iommu for spimdev
Date: Wed,  1 Aug 2018 18:22:16 +0800
Message-ID: <20180801102221.5308-3-nek.in.cn@gmail.com> (raw)
In-Reply-To: <20180801102221.5308-1-nek.in.cn@gmail.com>

From: Kenneth Lee <liguozhu@hisilicon.com>

This patch add sharing interface for a iommu_group. The new interface:

	iommu_group_share_domain()
	iommu_group_unshare_domain()

can be used by some virtual iommu_group (such as iommu_group for spimdev)
to share their parent's iommu_group.

When the domain of the group is shared, it cannot be changed before
unshared.  In the future, notification can be added if update is required.

Signed-off-by: Kenneth Lee <liguozhu@hisilicon.com>
---
 drivers/iommu/iommu.c | 28 +++++++++++++++++++++++++++-
 include/linux/iommu.h |  2 ++
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 63b37563db7e..a832aafe660d 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -54,6 +54,9 @@ struct iommu_group {
 	int id;
 	struct iommu_domain *default_domain;
 	struct iommu_domain *domain;
+	atomic_t domain_shared_ref; /* Number of user of current domain.
+				     * The domain cannot be modified if ref > 0
+				     */
 };
 
 struct group_device {
@@ -353,6 +356,7 @@ struct iommu_group *iommu_group_alloc(void)
 		return ERR_PTR(ret);
 	}
 	group->id = ret;
+	atomic_set(&group->domain_shared_ref, 0);
 
 	ret = kobject_init_and_add(&group->kobj, &iommu_group_ktype,
 				   NULL, "%d", group->id);
@@ -482,6 +486,25 @@ int iommu_group_set_name(struct iommu_group *group, const char *name)
 }
 EXPORT_SYMBOL_GPL(iommu_group_set_name);
 
+struct iommu_domain *iommu_group_share_domain(struct iommu_group *group)
+{
+	/* the domain can be shared only when the default domain is used */
+	/* todo: more shareable check */
+	if (group->domain != group->default_domain)
+		return ERR_PTR(-EINVAL);
+
+	atomic_inc(&group->domain_shared_ref);
+	return group->domain;
+}
+EXPORT_SYMBOL_GPL(iommu_group_share_domain);
+
+void iommu_group_unshare_domain(struct iommu_group *group)
+{
+	atomic_dec(&group->domain_shared_ref);
+	WARN_ON(atomic_read(&group->domain_shared_ref) < 0);
+}
+EXPORT_SYMBOL_GPL(iommu_group_unshare_domain);
+
 static int iommu_group_create_direct_mappings(struct iommu_group *group,
 					      struct device *dev)
 {
@@ -1401,7 +1424,8 @@ static int __iommu_attach_group(struct iommu_domain *domain,
 {
 	int ret;
 
-	if (group->default_domain && group->domain != group->default_domain)
+	if ((group->default_domain && group->domain != group->default_domain) ||
+	     atomic_read(&group->domain_shared_ref) > 0)
 		return -EBUSY;
 
 	ret = __iommu_group_for_each_dev(group, domain,
@@ -1438,6 +1462,8 @@ static void __iommu_detach_group(struct iommu_domain *domain,
 {
 	int ret;
 
+	WARN_ON(atomic_read(&group->domain_shared_ref) > 0);
+
 	if (!group->default_domain) {
 		__iommu_group_for_each_dev(group, domain,
 					   iommu_group_do_detach_device);
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 19938ee6eb31..278d60e3ec39 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -349,6 +349,8 @@ extern int iommu_domain_get_attr(struct iommu_domain *domain, enum iommu_attr,
 				 void *data);
 extern int iommu_domain_set_attr(struct iommu_domain *domain, enum iommu_attr,
 				 void *data);
+extern struct iommu_domain *iommu_group_share_domain(struct iommu_group *group);
+extern void iommu_group_unshare_domain(struct iommu_group *group);
 
 /* Window handling function prototypes */
 extern int iommu_domain_window_enable(struct iommu_domain *domain, u32 wnd_nr,
-- 
2.17.1


  parent reply index

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-01 10:22 [RFC PATCH 0/7] A General Accelerator Framework, WarpDrive Kenneth Lee
2018-08-01 10:22 ` [RFC PATCH 1/7] vfio/spimdev: Add documents for WarpDrive framework Kenneth Lee
2018-08-02  3:14   ` Tian, Kevin
2018-08-02  4:22     ` Kenneth Lee
2018-08-02  4:41       ` Tian, Kevin
2018-08-06 12:27   ` Pavel Machek
2018-08-08  1:43     ` Kenneth Lee
2018-08-01 10:22 ` Kenneth Lee [this message]
2018-08-02  3:17   ` [RFC PATCH 2/7] iommu: Add share domain interface in iommu for spimdev Tian, Kevin
2018-08-02  4:15     ` Kenneth Lee
2018-08-02  4:39       ` Tian, Kevin
2018-08-08  9:13   ` Joerg Roedel
2018-08-09  1:09     ` Kenneth Lee
2018-08-01 10:22 ` [RFC PATCH 3/7] vfio: add spimdev support Kenneth Lee
2018-08-01 16:23   ` Randy Dunlap
2018-08-02  3:07     ` Kenneth Lee
2018-08-02  3:21   ` Tian, Kevin
2018-08-02  3:47     ` Kenneth Lee
2018-08-02  4:24       ` Tian, Kevin
2018-08-02  7:34         ` Kenneth Lee
     [not found]           ` <20180802103528.0b863030.cohuck@redhat.com>
     [not found]             ` <20180802124327.403b10ab@t450s.home>
2018-08-06  1:40               ` Kenneth Lee
2018-08-06 15:49                 ` Alex Williamson
2018-08-06 16:34                   ` Raj, Ashok
2018-08-06 17:05                     ` Alex Williamson
2018-08-08  1:32                       ` Kenneth Lee
2018-08-01 10:22 ` [RFC PATCH 4/7] crypto: add hisilicon Queue Manager driver Kenneth Lee
2018-08-01 10:22 ` [RFC PATCH 5/7] crypto: Add Hisilicon Zip driver Kenneth Lee
2018-08-01 10:22 ` [RFC PATCH 6/7] crypto: add spimdev support to Hisilicon QM Kenneth Lee
2018-08-01 10:22 ` [RFC PATCH 7/7] vfio/spimdev: add user sample for spimdev Kenneth Lee
2018-08-01 16:56 ` [RFC PATCH 0/7] A General Accelerator Framework, WarpDrive Jerome Glisse
2018-08-02  2:33   ` Tian, Kevin
2018-08-02  4:05     ` Kenneth Lee
2018-08-02 14:22       ` Jerome Glisse
2018-08-03  3:47         ` Kenneth Lee
2018-08-03 14:39           ` Jerome Glisse
2018-08-06  3:12             ` Kenneth Lee
2018-08-06 15:32               ` Jerome Glisse
2018-08-08  1:08                 ` Kenneth Lee
2018-08-08 15:18                   ` Jerome Glisse
2018-08-09  8:03                     ` Kenneth Lee
2018-08-09  8:31                       ` Tian, Kevin
2018-08-10  1:37                         ` Kenneth Lee
2018-08-09 14:46                       ` Jerome Glisse
2018-08-10  3:39                         ` Kenneth Lee
2018-08-10 13:12                           ` Jean-Philippe Brucker
2018-08-11 15:26                             ` Kenneth Lee
2018-08-13  9:29                               ` Kenneth Lee
2018-08-13 19:23                                 ` Jerome Glisse
2018-08-14  3:46                                   ` Kenneth Lee
2018-08-10 14:32                           ` Jerome Glisse
2018-08-11 14:44                             ` Kenneth Lee
2018-08-02 10:10     ` Alan Cox
2018-08-02 12:24       ` Xu Zaibo
2018-08-02 14:46       ` Jerome Glisse
2018-08-03 14:20         ` Alan Cox
2018-08-03 14:55           ` Jerome Glisse
2018-08-06  1:26           ` Kenneth Lee
2018-08-02  2:59 ` Tian, Kevin
2018-08-02  3:40   ` Kenneth Lee
2018-08-02  4:36     ` Tian, Kevin
2018-08-02  5:35       ` Kenneth Lee

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