Thanks, Peter! That worked for me, Not sure if Virsh XML has some issue. for sake of other, this is the complete command I use.
/usr/bin/qemu-system-x86_64 -machine q35,kernel-irqchip=split,accel=kvm -smp 4 -m 2G -device intel-iommu,intremap=on,caching-mode=on -nographic os_image.qcow2 dmesg inside VM now shows [root@centos-8 ~]# dmesg | grep -e DMAR [ 0.013047] ACPI: DMAR 0x000000007FFE221F 000048 (v01 BOCHS BXPCDMAR 00000001 BXPC 00000001) [ 0.100861] DMAR: IOMMU enabled [ 0.258287] DMAR: Host address width 39 [ 0.259213] DMAR: DRHD base: 0x000000fed90000 flags: 0x1 [ 0.260470] DMAR: dmar0: reg_base_addr fed90000 ver 1:0 cap d2008c22260286 ecap f00f5a [ 0.262321] DMAR-IR: IOAPIC id 0 under DRHD base 0xfed90000 IOMMU 0 [ 0.263755] DMAR-IR: Queued invalidation will be enabled to support x2apic and Intr-remapping. [ 0.267498] DMAR-IR: Enabled IRQ remapping in x2apic mode [ 2.205498] DMAR: No RMRR found [ 2.207406] DMAR: No ATSR found [ 2.209495] DMAR: dmar0: Using Queued invalidation [ 2.212938] DMAR: Hardware identity mapping for device 0000:00:00.0 [ 2.216531] DMAR: Hardware identity mapping for device 0000:00:01.0 [ 2.219430] DMAR: Hardware identity mapping for device 0000:00:02.0 [ 2.222314] DMAR: Hardware identity mapping for device 0000:00:03.0 [ 2.224804] DMAR: Hardware identity mapping for device 0000:00:1f.0 [ 2.227289] DMAR: Hardware identity mapping for device 0000:00:1f.2 [ 2.229850] DMAR: Hardware identity mapping for device 0000:00:1f.3 [ 2.232185] DMAR: Setting RMRR: [ 2.233469] DMAR: Prepare 0-16MiB unity mapping for LPC [ 2.235443] DMAR: Ignoring identity map for HW passthrough device 0000:00:1f.0 [0x0 - 0xffffff] [ 2.238732] DMAR: Intel(R) Virtualization Technology for Directed I/O Thanks, Alok On Wed, Oct 7, 2020 at 1:53 AM Peter Xu <[email protected]> wrote: > On Tue, Oct 06, 2020 at 11:26:08PM +0530, Alok Prasad wrote: > > root@beta-hp-p70:/home/fastlinq/alok/KVM-VM# /usr/bin/qemu-system-x86_64 > > --version > > QEMU emulator version 4.2.1 > > Copyright (c) 2003-2019 Fabrice Bellard and the QEMU Project developers > > > > I am missing here something,? Is there seperate Branch for the same in > qemu. > > No, it should always be in mainline. > > I didn't see anything obviously wrong in your setup. A simplest QEMU > cmdline > to boot a guest with vIOMMU should be: > > $QEMU -machine q35,kernel-irqchip=split,accel=kvm -smp 4 -m 2G \ > -device intel-iommu ~/images/default.qcow2 > > May worth try this directly. Also feel free to compile the latest QEMU. > The > default configuration should work. > > -- > Peter Xu > >
