Re: [PATCH 08/12] iommufd/selftest: Put iopf enablement in domain attach path
From: Baolu Lu
Date: Thu Feb 20 2025 - 20:35:35 EST
On 2/21/25 02:00, Jason Gunthorpe wrote:
On Thu, Feb 20, 2025 at 03:03:21PM +0800, Baolu Lu wrote:
On 2/20/25 09:02, Jason Gunthorpe wrote:
On Fri, Feb 14, 2025 at 02:11:00PM +0800, Lu Baolu wrote:
@@ -197,11 +201,19 @@ static int mock_domain_nop_attach(struct iommu_domain *domain,
if (domain->dirty_ops && (mdev->flags & MOCK_FLAGS_DEVICE_NO_DIRTY))
return -EINVAL;
+ return mock_dev_enable_iopf(dev, domain);
+}
This isn't going to work for a replace type operation? Maybe like:
if (old_domain->iopf_handler && !domain->iopf_handler)
return mock_dev_disable_iopf(dev, domain);
if (old_domain->iopf_handler && domain->iopf_handler)
return 0;
return mock_dev_enable_iopf(dev, domain);
?
The iommufd mock device driver appears not to support replacement.
That's not technically a choice the driver gets to have ..
Yes.
The
replacement operation on this driver is likely handled as follows:
- attach domain_a attach blocking_domain attach domain_b
Nothing actually does that though?
Ah! you are right.
This driver allows a new domain to be set even if a domain already
exists. This is different from what vt-d driver does, which removes the
old domain first. So perhaps we need to enhance it in two ways:
- Store the existing domain (a.k.a. old domain).
- Handle iopf enablement, taking the existing domain into account.
How about below change?
diff --git a/drivers/iommu/iommufd/selftest.c
b/drivers/iommu/iommufd/selftest.c
index a6b12cee7b00..5ffbd4e3f372 100644
--- a/drivers/iommu/iommufd/selftest.c
+++ b/drivers/iommu/iommufd/selftest.c
@@ -168,6 +168,7 @@ struct mock_dev {
int id;
u32 cache[MOCK_DEV_CACHE_NUM];
unsigned int iopf_refcount;
+ struct iommu_domain *domain;
};
static inline struct mock_dev *to_mock_dev(struct device *dev)
@@ -197,17 +198,28 @@ static int mock_domain_nop_attach(struct
iommu_domain *domain,
struct device *dev)
{
struct mock_dev *mdev = to_mock_dev(dev);
+ int ret;
if (domain->dirty_ops && (mdev->flags &
MOCK_FLAGS_DEVICE_NO_DIRTY))
return -EINVAL;
- return mock_dev_enable_iopf(dev, domain);
+ if (mdev->domain)
+ mock_dev_disable_iopf(dev, mdev->domain);
+
+ ret = mock_dev_enable_iopf(dev, domain);
+ if (ret)
+ return ret;
+
+ mdev->domain = domain;
+ return 0;
}
Thanks,
baolu