On Fri, Oct 15, 2021 at 4:52 PM limingwang (A) <limingw...@huawei.com> wrote: > > > On Wed, Oct 13, 2021 at 22:41 PM Bin Meng <bin.m...@windriver.com> wrote: > > > > On Tue, Oct 12, 2021 at 9:46 AM MingWang Li <limingw...@huawei.com> wrote: > > > > > > From: Mingwang Li <limingw...@huawei.com> > > > > > > When I start the VM with the following command: > > > $ ./qemu-system-riscv64 -M virt,accel=kvm -m 4096M -cpu host -nographic \ > > > -name guest=riscv-guset \ > > > -smp 2 \ > > > -bios none \ > > > -kernel ./Image \ > > > -drive file=./guest.img,format=raw,id=hd0 \ > > > -device virtio-blk-device,drive=hd0 \ > > > -append "root=/dev/vda rw console=ttyS0 earlycon=sbi" \ > > > -object > > memory-backend-file,id=mem,size=4096M,mem-path=/dev/hugepages,share=on \ > > > -numa node,memdev=mem -mem-prealloc \ > > > -chardev socket,id=char0,path=/mnt/vhost-net0 \ > > > -netdev type=vhost-user,id=mynet1,chardev=char0,vhostforce \ > > > -device > > > virtio-net-pci,mac=52:54:00:00:00:01,netdev=mynet1,mrg_rxbuf=on,csum=o > > > n,guest_csum=on,guest_ecn=on \ > > > > > > Then, QEMU displays the following error information: > > > qemu-system-riscv64: Failed initializing vhost-user memory map, > > > consider using -object memory-backend-file share=on > > > > I see your command line parameters already contain "-object > > memory-backend-file > > share=on", so this error message is not accurate. > > QEMU uses this command to alloc fd in the "memory_region_init_ram_from_file" > function > and assigns the value of fd to mr->ram_block-fd. If the QEMU uses the default > memory to > initialize the system, the QEMU cannot obtain the fd in the > "vhost_user_mem_section_filter" > function when initializing the vhost-user. As a result, an error is reported > in the "vhost_user_fill_set_mem_table_msg" > function. > > Because of the above bug, even if "-object memory-backend-file share=on" is > added to the command line, > the QEMU still reports an error.
Yes, what I meant is that QEMU should not report such inaccurate messages because of some random codes elsewhere. With current message, it suggested user use "-object memory-backend-file share=on" in the command line, but it is already used. So this is a false alarm. The "bug" is somewhere else. > This patch can solve this bug. > > > Should this message be altered to mention things like what this patch does? > > Thanks, I will rewrite the message in next version. > > > > > qemu-system-riscv64: vhost_set_mem_table failed: Interrupted system > > > call (4) > > > qemu-system-riscv64: unable to start vhost net: 4: falling back on > > > userspace virtio > > > > > > Note that, before starting the kvm-acceled QEMU VM, following > > > temporarily unaccepted QEMU patches should be used: > > > https://lists.gnu.org/archive/html/qemu-devel/2021-08/msg02516.html > > > > > > This error was made bacause default main_mem is used to be registered > > > > typo: because > > > Thanks. > > > > as the system memory, other memory cannot be initialized. Therefore, > > > the system memory should be initialized to the machine->ram, which > > > consists of the default main_mem and other possible memory required by > > > applications, such as shared hugepage memory in DPDK. > > > Also, the mc->defaul_ram_id should be set to the default main_mem, > > > such as "riscv_virt_board.ram" for the virt machine. > > > > > > > How about changing the commit title to: "Use machine->ram as the system > > memory" ?? > > > > I think it is just a bugfix. > But the current codes run perfectly okay so far. This patch adds an additional use case for the KVM scenario where current codes cannot handle. Regards, Bin
