[RFC PATCH v1 00/18] Provide a new two step DMA API mapping API

[Leon Romanovsky]

On Wed, Jul 03, 2024 at 04:35:30PM +0200, Christoph Hellwig wrote:
> On Wed, Jul 03, 2024 at 01:52:53PM +0300, Leon Romanovsky wrote:
> > On Wed, Jul 03, 2024 at 07:42:38AM +0200, Christoph Hellwig wrote:
> > > I just tried to boot this on my usual qemu test setup with emulated
> > > nvme devices, and it dead-loops with messages like this fairly late
> > > in the boot cycle:
> > > 
> > > [   43.826627] iommu: unaligned: iova 0xfff7e000 pa 0x000000010be33650 size 0x1000 min_pagesz 0x1000
> > > [   43.826982] dma_mapping_error -12
> > > 
> > > passing intel_iommu=off instead of intel_iommu=on (expectedly) makes
> > > it go away.
> > 
> > Can you please share your kernel command line and qemu?
> > On my and Chaitanya setups it works fine.
> 
> qemu-system-x86_64 \
>         -nographic \
> 	-enable-kvm \
> 	-m 6g \
> 	-smp 4 \
> 	-cpu host \
> 	-M q35,kernel-irqchip=split \
> 	-kernel arch/x86/boot/bzImage \
> 	-append "root=/dev/vda console=ttyS0,115200n8 intel_iommu=on" \
>         -device intel-iommu,intremap=on \
> 	-device ioh3420,multifunction=on,bus=pcie.0,id=port9-0,addr=9.0,chassis=0 \	
>         -blockdev driver=file,cache.direct=on,node-name=root,filename=/home/hch/images/bookworm.img \
> 	-blockdev driver=host_device,cache.direct=on,node-name=test,filename=/dev/nvme0n1p4 \
> 	-device virtio-blk,drive=root \
> 	-device nvme,drive=test,serial=1234

Thanks, Chaitanya will take a look.

If we put aside this issue, do you think that the proposed API is the right one?

BTW, I have more fancy command line, it is probably the root cause of working/not-working:
/opt/simx/bin/qemu-system-x86_64
        -append root=/dev/root rw ignore_loglevel rootfstype=9p
        rootflags="cache=loose,trans=virtio" earlyprintk=serial,ttyS0,115200
                console=hvc0 noibrs noibpb nopti nospectre_v2 nospectre_v1
                l1tf=off nospec_store_bypass_disable no_stf_barrier mds=off
                mitigations=off panic_on_warn=1
                intel_iommu=on iommu=nopt iommu.forcedac=true
                vfio_iommu_type1.allow_unsafe_interrupts=1
                systemd.hostname=mtl-leonro-l-vm
        -chardev stdio,id=stdio,mux=on,signal=off   
        -cpu host                                  
        -device virtio-rng-pci                    
        -device virtio-balloon-pci               
        -device isa-serial,chardev=stdio        
        -device virtio-serial-pci              
        -device virtconsole,chardev=stdio     
        -device virtio-9p-pci,fsdev=host_fs,mount_tag=/dev/root  
        -device virtio-9p-pci,fsdev=host_bind_fs0,mount_tag=bind0
        -device virtio-9p-pci,fsdev=host_bind_fs1,mount_tag=bind1
        -device virtio-9p-pci,fsdev=host_bind_fs2,mount_tag=bind2
        -device intel-iommu,intremap=on 
        -device connectx7              
        -device nvme,drive=drv0,serial=foo 
        -drive file=/home/leonro/.cache/mellanox/mkt/nvme-1g.raw,if=none,id=drv0,format=raw 
        -enable-kvm                                                                        
        -fsdev local,id=host_bind_fs1,security_model=none,path=/logs          
        -fsdev local,id=host_fs,security_model=none,path=/mnt/self           
        -fsdev local,id=host_bind_fs0,security_model=none,path=/plugins     
        -fsdev local,id=host_bind_fs2,security_model=none,path=/home/leonro
        -fw_cfg etc/sercon-port,string=2  
        -kernel /home/leonro/src/kernel/arch/x86/boot/bzImage 
        -m 5G -machine q35,kernel-irqchip=split              
        -mon chardev=stdio                                  
        -net nic,model=virtio,macaddr=52:54:01:d8:e5:f9    
        -net user,hostfwd=tcp:127.0.0.1:46645-:22  
        -no-reboot -nodefaults -nographic -smp 16 -vga none 

> 
>