On Wed, May 28, 2025 at 08:12:41AM +0000, Tian, Kevin wrote:

quoted

From: Nicolin Chen <redacted>
Sent: Saturday, May 24, 2025 5:46 AM

On Fri, May 23, 2025 at 07:55:18AM +0000, Tian, Kevin wrote:

quoted

quoted

From: Nicolin Chen <redacted>
Sent: Sunday, May 18, 2025 11:22 AM

+
+enum iommufd_viommu_flags {
+	/*
+	 * The HW does not go through an address translation table but
reads the
+	 * physical address space directly: iommufd core should pin the
physical
+	 * pages backing the queue memory that's allocated for the HW
QUEUE, and
+	 * ensure those physical pages are contiguous in the physical space.
+	 */
+	IOMMUFD_VIOMMU_FLAG_HW_QUEUE_READS_PA = 1 << 0,
+};

The queue itself doesn't read an address.

What about 'QUEUE_BASE_PA'?

But the HW queue object represents the HW feature, not the guest
queue memory. So, it is accurate to say that it reads an address?

We have this in doc:
- IOMMUFD_OBJ_HW_QUEUE, representing a hardware accelerated queue,
as a subset
  of IOMMU's virtualization features, for the IOMMU HW to directly read or
write
  the virtual queue memory owned by a guest OS. This HW-acceleration
feature can
  ...

Okay. Then ACCESS_PA means both read/write?

OK. IOMMUFD_VIOMMU_FLAG_HW_QUEUE_ACCESS_PA