> From: Liu, Yi L <yi.l.liu@xxxxxxxxx>
> Sent: Thursday, May 11, 2023 10:51 PM
>
> 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(-)
>
> diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
> index 1c5e1d88862b..e818520f4068 100644
> --- a/drivers/iommu/intel/iommu.h
> +++ b/drivers/iommu/intel/iommu.h
> @@ -596,15 +596,38 @@ struct dmar_domain {
> spinlock_t lock; /* Protect device tracking lists */
> struct list_head devices; /* all devices' list */
>
> - struct dma_pte *pgd; /* virtual address */
> - int gaw; /* max guest address width */
> -
> - /* adjusted guest address width, 0 is level 2 30-bit */
> - int agaw;
> int iommu_superpage;/* Level of superpages supported:
> 0 == 4KiB (no superpages), 1 ==
> 2MiB,
> 2 == 1GiB, 3 == 512GiB, 4 == 1TiB */
> - u64 max_addr; /* maximum mapped address */
> + union {
> + /* DMA remapping domain */
> + struct {
> + /* virtual address */
> + struct dma_pte *pgd;
> + /* max guest address width */
> + int gaw;
> + /*
> + * adjusted guest address width:
> + * 0: level 2 30-bit
> + * 1: level 3 39-bit
> + * 2: level 4 48-bit
> + * 3: level 5 57-bit
> + */
> + int agaw;
> + /* maximum mapped address */
> + u64 max_addr;
> + };
what about 'nid'?
> +
> + /* Nested user domain */
> + struct {
> + /* 2-level page table the user domain nested */
/* parent page table which the user domain is nested on */
> + 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;
> + };
> + };
>
> struct iommu_domain domain; /* generic domain data structure for
> iommu core */
> --
> 2.34.1
