I am using linux 4.0 kernel on host side and 3.19 on guest side.
I have enabled the iommu and nested virtualization on host.
The DMAR is visible in the host side and when I start a VM using qemu-kvm, the same DMAR not visible on the guest side. But it says IOMMU is enabled when I look at dmesg.
sudo qemu-system-x86_64 -machine q35 -m 3G -enable-kvm -smp 4 \
-cpu kvm64,-kvm_pv_eoi,-kvm_steal_time,-kvm_asyncpf,-kvmclock,+vmx,+x2apic \
-net nic,macaddr=52:54:00:37:4d:10 \
-net tap,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown \
-drive file=ubuntu_15.qcow,id=disk,if=none \
-device ide-hd,drive=disk -serial stdio -serial vc \
-device intel-hda,addr=1b.0 -device hda-duplex
Please let me know am I missing something here? how can I resolve this.