On 5/24/23 3:02 PM, Tian, Kevin wrote:
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'?
"nid" represents which NUMA node should we allocate pages from for this domain. It's updated every time when a domain is attached/detached to/from a device or pasid. Generally speaking, "nid" is common for all types of domain. But in this case, only a DMA remapping domain has a need to allocate pages. I intend to keep it as it for now. There's more cleanup rooms if we limit it only for DMA remapping domain. Best regards, baolu
