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@xxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx>
Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
---
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
