From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 6 Aug 2019 10:42:59 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20190806094259.GC3066@work-vm> References: <5D4944CC.30100@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5D4944CC.30100@huawei.com> Subject: Re: [Virtio-fs] [QUESTION] Can not enable dax option List-Id: Development discussions about virtio-fs List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: piaojun Cc: virtio-fs@redhat.com * piaojun (piaojun@huawei.com) wrote: > Hi, > > Dax could not be enabled by run the following command: > > QEMU command: > qemu-system-x86_64 -M pc -cpu host --enable-kvm -smp 2 \ > -m 4G,maxmem=4G -object memory-backend-file,id=mem,size=4G,mem-path=/dev/shm,share=on -numa node,memdev=mem \ > -drive if=none,id=root,format=qcow2,file=centos_7.3_64.qcow2 -device virtio-scsi -device scsi-disk,drive=root,bootindex=1 -object iothread,id=io \ > -device virtio-scsi-pci,iothread=io -net nic,model=virtio -vnc 0.0.0.0:0 \ > -chardev socket,id=char0,path=/tmp/vhostqemu -device vhost-user-fs-pci,queue-size=1024,chardev=char0,tag=myfs,cache-size=2G > > Guest command: > # mount -t virtio_fs myfs /mnt/virtiofs -o rootmode=040000,user_id=0,group_id=0,dax > > When I rmmod/insmod again, the error message shows that something is > wrong with 'cache capability': > > virtio_pci_find_shm_cap: shm cap with bad size offset: 164 size: 24 > virtio_fs virtio2: virtio_fs_setup_dax: No cache capability That's odd; because '24' seems the right size for a 'struct virtio_pci_cap64' and is what I get on my machine. Can you add: diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c index fcdabe85d82d..34e89474a8b7 100644 --- a/drivers/virtio/virtio_pci_modern.c +++ b/drivers/virtio/virtio_pci_modern.c @@ -473,6 +473,7 @@ static int virtio_pci_find_shm_cap(struct pci_dev *dev, __func__, pos, cap_len); continue; } + printk(KERN_INFO "%s: cap_len should be: %d\n", __func__, sizeof(struct virtio_pci_cap64)); pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap, id), and tell us what it says? Just check that your kernel's include/uapi/linux/virtio_pci.h and daemon's include/standard-headers/linux/virtio_pci.h both match and show the same definition for virtio_pci_cap64 Dave > > Code url: > https://github.com/rhvgoyal/linux/commits/virtio-fs-dev-5.1 > https://gitlab.com/virtio-fs/qemu/tree/virtio-fs-dev > > Thanks, > Jun > > _______________________________________________ > Virtio-fs mailing list > Virtio-fs@redhat.com > https://www.redhat.com/mailman/listinfo/virtio-fs -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK