I’m writing a custom NVMe device model and I need to test ATS functionality. For that, I need to enable the IOMMU.
I start QEMU with the following command line, using a stock Ubuntu 16.04 image: % emu-system-x86_64 -M q35,accel=kvm,kernel_irqchip=off -m 8K -device intel-iommu,intremap=on,device-iotlb=on -device myNVMe,addr=10.0 It boots just fine and I see the /dev/nvme* device files, but the addresses provided for DMA transfers are the same as without a IOMMU. I see there are no iommu groups defined, and thus my device is obviously not assigned to any one of them. DMAR-related syslog messages: ACPI: DMAR 0x000000007FFE20C5 000050 (v01 BOCHS. BXPCDMAR 00000001 BXPC 00000001) DMAR: Host address width 39 DMAR: DRHD base: 0x000000fed90000 flags: 0x1 DMAR: dmar0: reg_base_addr fed90000 ver 1.0 cap 12008c22260206 cap f00f4e DMAR: ATSR flash: 0x1 DMAR-IR: IOAPIC id 0 under DRHD base. 0xfed90000 IOMMU 0 DMAR-IR: Enabled IRQ remapping in Salic mode How can I get the DMA buffers use virtual addresses?
