x86: 0.956 device: 0.945 peripherals: 0.914 graphic: 0.910 architecture: 0.874 network: 0.865 hypervisor: 0.861 kernel: 0.813 PID: 0.801 performance: 0.796 socket: 0.766 ppc: 0.759 virtual: 0.748 permissions: 0.700 register: 0.679 semantic: 0.655 vnc: 0.647 debug: 0.575 assembly: 0.569 risc-v: 0.533 VMM: 0.507 arm: 0.454 TCG: 0.440 KVM: 0.409 boot: 0.403 i386: 0.399 user-level: 0.383 files: 0.341 mistranslation: 0.287 vsock device fails with "qemu-system-x86_64: vhost_set_features failed: Operation not supported (95)" when queue_reset=true Description of problem: Immediately after guest vsock driver initialize, qemu prints error messages. I'm not able to connect to the guest with vsock: ``` [ 0.654463] Run /init as init process [ 0.679778] NET: Registered PF_VSOCK protocol family qemu-system-x86_64: vhost_set_features failed: Operation not supported (95) qemu-system-x86_64: Error starting vhost: 95 ssh-keygen: generating new host keys: RSA DSA ECDSA ED25519 # ``` Steps to reproduce: 1. Clone `git://passt.top/passt` 2. In `passt/test`, run `make mbuto.img` 3. Run `qemu-system-x86_64 -enable-kvm -m 2048 -kernel KERNEL -initrd mbuto.img -nographic -serial stdio -nodefaults -append "console=ttyS0" -device vhost-vsock-pci,guest-cid=31415,queue_reset=true` replacing KERNEL with the host kernel image. Additional information: - Problem goes away if `queue_reset=false`, which means it goes away with default options prior to `69e1c14aa222` ("virtio: core: vq reset feature negotation support") - Occurs both with and without KVM