On 4/15/24 7:54 PM, Jason Gunthorpe wrote:
On Mon, Apr 15, 2024 at 01:32:03PM +0800, Baolu Lu wrote:
On 4/12/24 4:15 PM, Yi Liu wrote:
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 40dd439307e8..1e5e9249c93f 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -631,7 +631,7 @@ struct iommu_ops {
struct iommu_domain_ops {
int (*attach_dev)(struct iommu_domain *domain, struct device *dev);
int (*set_dev_pasid)(struct iommu_domain *domain, struct device *dev,
- ioasid_t pasid);
+ ioasid_t pasid, struct iommu_domain *old);
Is it possible to add another op to replace a domain for pasid? For
example,
int (*replace_dev_pasid)(domain, dev, pasid, old_domain)
We haven't needed that in the normal case, what would motivate it
here?
My understanding of the difference between set_dev_pasid and
replace_dev_pasid is that the former assumes that there is no domain
attached to the pasid yet, so it sets the passed domain to it. For the
latter, it simply replaces the existing domain with a new one.
The set_dev_pasid doesn't need an old domain because it's assumed that
the existing domain is NULL. The replace_dev_pasid could have an
existing domain as its input.
Replace also implies an atomic switch between different domains. This
makes it subtly different from a set operation.
Best regards,
baolu
