Re: [Qemu-devel] [PATCH for 2.1] ppc: fix -mem-path failure

[Alexander Graf <agraf@suse.de>]

On 07/21/2014 11:30 AM, Hu Tao wrote:
> commit e938ba0c tried to enable -mem-path for ppc but breaked some ppc
> boards.
>
> The problems are:
>
> 1. it fails when allocating memory for rom, sram whose sizes are less
>     than huge page size:
>
>     ./ppc-softmmu/qemu-system-ppc  -m 512 -mem-path /hugepages/ \
>     -kernel /home/hutao/Downloads/vmlinux-ppc -initrd \
>     /home/hutao/Downloads/initrd-ppc.gz
>     qemu-system-ppc: /mnt/data/projects/qemu/exec.c:1184: qemu_ram_set_idstr: Assertion `new_block' failed.
>
> 2. if there is a numa node backed by memory backend object, qemu fails
>     with message:
>
>     ./ppc-softmmu/qemu-system-ppc  -m 512 \
>     -object memory-backend-file,size=512M,mem-path=/hugepages,id=f0 \
>     -numa node,nodeid=0,memdev=f0 \
>     -kernel /home/hutao/Downloads/vmlinux-ppc \
>     -initrd /home/hutao/Downloads/initrd-ppc.gz
>     qemu-system-ppc: memory backend f0 is used multiple times. Each -numa option must use a different memdev value.
>
> This patch does following:
>
> 1. replaces memory_region_allocate_system_memory() with
>     memory_region_init_ram() for rom, sram. Then only system memory
>     is backed by hugepages when specifying mem-path.
>
> 2. for memory banks, allocates all ram with
>     one memory_region_allocate_system_memory(), and use
>     memory_region_init_alias() to initialize memory banks.
>
> Tested machines: default(g3beige), mac99, taihu, bamboo, ref405ep.
>
> Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>

Thanks, this makes a lot of sense.

I've applied this to ppc-next (for 2.1) and kicked off an autotest run. 
If that's successful, I'll send a pull request to Peter ASAP.


Alex