Hi, Does QEMU support MIPS smp 2 malta board?
$ qemu-system-mipsel -M malta -kernel vmlinux -initrd ramfs.cpio.gz \ -append "console=ttyS0 root=/dev/ram0 maxcpus=2" -nographic -s \ -smp 2 Linux version 3.11.0-rc6 (yrtan@localhost.localdomain) (gcc version 4.7.2 (Sourcery CodeBench Lite 2012.09-99) ) #4 SMP Thu Oct 31 09:21:01 CST 2013 bootconsole [early0] enabled CPU revision is: 00019300 (MIPS 24Kc) FPU revision is: 00739300 Software DMA cache coherency enabled Determined physical RAM map: memory: 00001000 @ 00000000 (reserved) memory: 000ef000 @ 00001000 (ROM data) memory: 004cf000 @ 000f0000 (reserved) memory: 07a41000 @ 005bf000 (usable) Wasting 47072 bytes for tracking 1471 unused pages Initial ramdisk at: 0x805bf000 (2614602 bytes) Zone ranges: DMA [mem 0x00000000-0x00ffffff] Normal [mem 0x01000000-0x07ffffff] Movable zone start for each node Early memory node ranges node 0: [mem 0x00000000-0x07ffffff] Primary instruction cache 2kB, VIPT, 2-way, linesize 16 bytes. Primary data cache 2kB, 2-way, VIPT, no aliases, linesize 16 bytes PERCPU: Embedded 7 pages/cpu @81103000 s6656 r8192 d13824 u32768 Built 1 zonelists in Zone order, mobility grouping on. Total pages: 32512 Kernel command line: rd_start=0xffffffff805bf000 rd_size=2614602 console=ttyS0 root=/dev/ram0 PID hash table entries: 512 (order: -1, 2048 bytes) Dentry cache hash table entries: 16384 (order: 4, 65536 bytes) Inode-cache hash table entries: 8192 (order: 3, 32768 bytes) Writing ErrCtl register=00000000 Readback ErrCtl register=00000000 Memory: 121464K/131072K available (3668K kernel code, 201K rwdata, 648K rodata, 208K init, 122K bss, 9608K reserved) Hierarchical RCU implementation. RCU restricting CPUs from NR_CPUS=2 to nr_cpu_ids=1. NR_IRQS:256 Linux version 3.11.0-rc6 (yrtan@localhost.localdomain) (gcc version 4.7.2 (Sourcery CodeBench Lite 2012.09-99) ) #4 SMP Thu Oct 31 09:21:01 CST 2013 bootconsole [early0] enabled CPU revision is: 00019300 (MIPS 24Kc) FPU revision is: 00739300 Skipping PCI bus scan due to resource conflict Software DMA cache coherency enabled Determined physical RAM map: memory: 00001000 @ 00000000 (reserved) memory: 000ef000 @ 00001000 (ROM data) memory: 004cf000 @ 000f0000 (reserved) memory: 07a41000 @ 005bf000 (usable) Wasting 47072 bytes for tracking 1471 unused pages Initrd not found or empty - disabling initrd Zone ranges: DMA [mem 0x00000000-0x00ffffff] Normal [mem 0x01000000-0x07ffffff] Movable zone start for each node Early memory node ranges node 0: [mem 0x00000000-0x07ffffff] ------------[ cut here ]------------ WARNING: CPU: 0 PID: 0 at mm/page_alloc.c:4796 free_area_init_node+0x38c/0x3c0() Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.11.0-rc6 #4 Stack : 00000006 00000004 00000000 00000000 00000000 00000000 805ae5b6 00000037 805b0000 00000000 8057783c 80551280 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 8053bd00 8053bd14 804eee0c 80550fa7 8016c714 805b0000 804eee0c 00000000 00000000 80551280 805a3f1c 80550f66 8053bc90 ... Call Trace: [<801093a8>] show_stack+0x64/0x7c [<8048f840>] dump_stack+0x64/0x84 [<8012d374>] warn_slowpath_common+0x84/0xb4 [<8012d3bc>] warn_slowpath_null+0x18/0x24 [<8057783c>] free_area_init_node+0x38c/0x3c0 [<80577d9c>] free_area_init_nodes+0x518/0x554 [<805732a4>] paging_init+0x2c/0x38 [<805715f8>] setup_arch+0x488/0x60c [<8056c63c>] start_kernel+0x84/0x3d4 [<8048bf70>] kernel_entry+0x0/0xa8 ---[ end trace 4eaa2a86a8e2da22 ]--- Primary instruction cache 2kB, VIPT, 2-way, linesize 16 bytes. Primary data cache 2kB, 2-way, VIPT, no aliases, linesize 16 bytes There's no problem while I removing "-smp 2" option. (plus the kernel MIPS configure file " malta_defconfig" support smp 2 ) -- Best Regards, Yu Rong Tan