On Wed, Jun 21, 2023 at 08:29:09AM +0000, Duan, Zhenzhong wrote:
-----Original Message----- From: Jason Gunthorpe jgg@nvidia.com Sent: Tuesday, June 20, 2023 8:47 PM Subject: Re: [PATCH v2 00/11] iommufd: Add nesting infrastructure
On Tue, Jun 20, 2023 at 01:43:42AM +0000, Tian, Kevin wrote:
I wonder whether we have argued passed each other.
This series adds reserved regions to S2. I challenged the necessity as S2 is not directly accessed by the device.
Then you replied that doing so still made sense to support identity S1.
I think I said/ment if we attach the "s2" iommu domain as a direct attach for identity - eg at boot time, then the IOAS must gain the reserved regions. This is our normal protocol.
There is code to fail the attaching for device with RMRR in intel iommu driver, do we plan to remove below check for IOMMUFD soon or later?
static int intel_iommu_attach_device(struct iommu_domain *domain, struct device *dev) { struct device_domain_info *info = dev_iommu_priv_get(dev); int ret;
if (domain->type == IOMMU_DOMAIN_UNMANAGED && device_is_rmrr_locked(dev)) { dev_warn(dev, "Device is ineligible for IOMMU domain attach due to platform RMRR requirement. Contact your platform vendor.\n"); return -EPERM; }
Not really, systems with RMRR cannot support VFIO at all. Baolu sent a series lifting this restriction up higher in the stack:
https://lore.kernel.org/all/20230607035145.343698-1-baolu.lu@linux.intel.com...
Jason