On Wed, Aug 07, 2024 at 02:41:39PM +0800, Baolu Lu wrote:
On 2024/8/7 1:12, Jason Gunthorpe wrote:I get it, but you can't have ATS turned on at all if you can push the
On Tue, Aug 06, 2024 at 10:39:38AM +0800, Lu Baolu wrote:Yes.
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.cThis seems really strange, maybe wrong..
index c019fb3b3e78..f37c8c3cba3c 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -1270,6 +1270,9 @@ void domain_update_iotlb(struct dmar_domain *domain)
bool has_iotlb_device = false;
unsigned long flags;
+ if (!domain)
+ return;
+
The only callers that could take advantage are
iommu_enable_pci_caps()/iommu_disable_pci_caps()
When the PCI ATS status changes, the domain attached to the device
should have its domain->has_iotlb_device flag updated.
The global static identity domain is a dummy domain without a
corresponding dmar_domain structure. Consequently, the device's
info->domain will be NULL. This is why a check is necessary.
invalidations. So it seems like something is missing to enforce that
with the identity domains.
Not any more, that was removed in commit 06792d067989 ("iommu/vt-d:So I looked at this and, uh, who even reads domain->has_iotlb_device ?The has_iotlb_device flag indicates whether a domain is attached to
devices with ATS enabled. If a domain lacks this flag, no device TBLs
need to be invalidated during unmap operations. This optimization avoids
unnecessary looping through all attached devices.
Cleanup use of iommu_flush_iotlb_psi()")
This compiles, so you should do this instead: