[Qemu-devel] Re: [PATCH] pc: unbreak vhost

[Alex Williamson]

On Fri, 2010-07-16 at 14:00 +0300, Michael S. Tsirkin wrote:
> Commit 44ae28f3152138e71ccad66c201d730b93374bc2 breaks vhost
> on small guests as we get a zero-sized memory slot at >4G,
> which that code does not expect.
> The removal of if (above_4g_size > 0) seems unintentional
> (commit log only mentions allocation memory in a single chunk)
> so just put it back in.

Yep, I already submitted an identical patch too:

http://lists.nongnu.org/archive/html/qemu-devel/2010-07/msg00364.html

Alex

> Signed-off-by: Michael S. Tsirkin <address@hidden>
> ---
>  hw/pc.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/pc.c b/hw/pc.c
> index 89bd4af..77b1592 100644
> --- a/hw/pc.c
> +++ b/hw/pc.c
> @@ -920,8 +920,10 @@ void pc_memory_init(ram_addr_t ram_size,
>                   below_4g_mem_size - 0x100000,
>                   ram_addr + 0x100000);
>  #if TARGET_PHYS_ADDR_BITS > 32
> -    cpu_register_physical_memory(0x100000000ULL, above_4g_mem_size,
> -                                 ram_addr + below_4g_mem_size);
> +    if (above_4g_mem_size > 0) {
> +        cpu_register_physical_memory(0x100000000ULL, above_4g_mem_size,
> +                                     ram_addr + below_4g_mem_size);
> +    }
>  #endif
>  
>      /* BIOS load */