> > When dmar_readq or devmem2 read the DW of IQA always 0UL because > > "& VTD_IQA_QS". So, try to fix it. > > > > case: > > after vtd_mem_write > > IQA val: 0x100206801 > > > > after vtd_mem_read > > IQA val: 0x100206001 > > > > Signed-off-by: yeeli <seven.yi....@gmail.com> > > > how was this tested?
If VT-D hardware supports scalable mode, Linux will set the IQA DW (bit 11). In qemu, the vtd_mem_write and vtd_update_iq_dw set DW well, however, vtd_mem_read the DW wrong because "& VTD_IQA_QS" dropped the value of DW (bit 11). So testing the patch is easy, config the "x-scalable-mode" option as below: "-device intel-iommu,caching-mode=on,x-scalable-mode=on,aw-bits=48" after Linux OS boot, check the IQA_REG DW (bit 11) as below: IOMMU_DEBUGFS: "cat /sys/kernel/debug/iommu/intel |grep IQA" "IQA 0x90 0x00000001001da801" or devmem2 read the reg: "devmem2 0xfed90090" "/dev/mem opened." "Memory mapped at address 0x7f983014f000." "Value at address 0xFED90090 (0x7f983014f000): 0x0"
