On 3/20/23 9:54 PM, Jason Gunthorpe wrote:
On Thu, Mar 09, 2023 at 12:22:05AM -0800, Yi Liu wrote:
From: Lu Baolu baolu.lu@linux.intel.com
The nested domain fields are exclusive to those that used for a DMA remapping domain. Use union to avoid memory waste.
Signed-off-by: Lu Baolu baolu.lu@linux.intel.com Signed-off-by: Yi Liu yi.l.liu@intel.com
drivers/iommu/intel/iommu.h | 35 +++++++++++++++++++++++++++++------ 1 file changed, 29 insertions(+), 6 deletions(-)
Using unions like this often devolves into a mess.
You'd be better to have more structures
struct intel_iommu_domain { struct iommu_domain domain; [general fields about attachment] };
struct intel_iopte_domain { struct intel_iommu_domain domain; [stuff describing the io page table data, pgd, format, etc] };
strut intel_s1_domain { struct intel_iommu_domain domain; struct dmar_domain *s2_domain; /* user page table pointer (in GPA) */ unsigned long s1_pgtbl; /* page table attributes */ struct iommu_hwpt_intel_vtd s1_cfg; }; static_assert(offset_of(struct intel_s1_domain, domain.domain) == offset_of(struct intel_iommu_domain, domain));
The per-domain ops allow to make this work sensibly
Yes. This will make the data structures clearer.
However, this will lead to significant code changes. I think it would be more appropriate to put it in a separate refactoring series later.
Best regards, baolu