Hello Robert,
On 24/03/2015 16:42, Robbie VanVossen wrote:
If multiple devices are being passed through to the same domain and they
share a single SMMU, then they only require a single iommu_domain.
In arm_smmu_assign_dev, before a new iommu_domain is created, the
xen_domain->contexts is checked for any iommu_domains that are already
assigned to device that uses the same SMMU as the current device. If one
is found, attach the device to that iommu_domain. If a new one isn't
found, create a new iommu_domain just like before.
The arm_smmu_deassign_dev function assumes that there is a single
device per iommu_domain. This meant that when the first device was
deassigned, the iommu_domain was freed and when another device was
deassigned a crash occured in xen.
To fix this, a reference counter was added to the iommu_domain struct.
When an arm_smmu_xen_device references an iommu_domain, the
iommu_domains ref is incremented. When that reference is removed, the
iommu_domains ref is decremented. The iommu_domain will only be freed
when the ref is 0.
Signed-off-by: Robbie VanVossen <robert.vanvos...@dornerworks.com>
---
Changed since v2:
* Fixed coding style
* Removed an unnecessary error message
* Added some helper functions to clean up the workflow in
arm_smmu_assign_dev a bit
Changed since v1:
* Fixed coding style for comments
* Move increment/decrement outside of attach/detach functions
* Expanded xen_domain->lock to protect more of the assign/deassign
functions
* Removed iommu_domain add/remove_device functions
---
xen/drivers/passthrough/arm/smmu.c | 99 ++++++++++++++++++++++++++----------
1 file changed, 71 insertions(+), 28 deletions(-)
diff --git a/xen/drivers/passthrough/arm/smmu.c
b/xen/drivers/passthrough/arm/smmu.c
index a7a7da9..be0ecdc 100644
--- a/xen/drivers/passthrough/arm/smmu.c
+++ b/xen/drivers/passthrough/arm/smmu.c
@@ -223,6 +223,7 @@ struct iommu_domain
/* Runtime SMMU configuration for this iommu_domain */
struct arm_smmu_domain *priv;
+ atomic_t ref;
/* Used to link iommu_domain contexts for a same domain.
* There is at least one per-SMMU to used by the domain.
* */
@@ -2564,12 +2565,45 @@ static void arm_smmu_iotlb_flush(struct domain *d,
unsigned long gfn,
arm_smmu_iotlb_flush_all(d);
}
+static struct iommu_domain *arm_smmu_get_domain(struct domain *d,
+ struct device
*dev)
The indentation is wrong here.
[..]
- spin_lock(&xen_domain->lock);
- /* Chain the new context to the domain */
- list_add(&domain->list, &xen_domain->contexts);
- spin_unlock(&xen_domain->lock);
+ /* Chain the new context to the domain */
+ list_add(&domain->list, &xen_domain->contexts);
+
This line contains trailing white-space.
Other than this 2 nits:
Reviewed-by: Julien Grall <julien.gr...@linaro.org>
Regards,
--
Julien Grall
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