Re: pvgrub "Error 9: Unknown boot failure" booting Debian Jessie kernel (Was: Re: [PATCH v5 6/9] libxc: create unmapped initrd in domain builder if supported)

[Wei Liu <wei.liu2@citrix.com>]

On Tue, Dec 01, 2015 at 10:04:38AM +0000, Ian Campbell wrote:
> On Tue, 2015-12-01 at 10:01 +0000, Ian Campbell wrote:
> > 
> > > > I'll try that and your suggested patch below as well once I get to the
> > > > office this morning.
> > > 
> > > Thanks.
> > 
> > The BUG_ON doesn't seem to be triggering. I'm not seeing pfn==0x4d80 going
> > anywhere near kexec_allocate, the highest is 0x4c0f.
> > 
> > Maybe the issue is that the ->allocate hook (==kexec_allocate) isn't called
> > from xc_dom_alloc_pad?
> 
> That seems like it might be the answer, this patchlet fixes it for me:
> 
> diff --git a/tools/libxc/xc_dom_core.c b/tools/libxc/xc_dom_core.c
> index 5d6c3ba..6d3f97a 100644
> --- a/tools/libxc/xc_dom_core.c
> +++ b/tools/libxc/xc_dom_core.c
> @@ -579,7 +579,13 @@ static int xc_dom_alloc_pad(struct xc_dom_image *dom, xen_vaddr_t boundary)
>      }
>      pages = (boundary - dom->virt_alloc_end) / page_size;
>  
> -    return xc_dom_chk_alloc_pages(dom, "padding", pages);
> +    if ( xc_dom_chk_alloc_pages(dom, "padding", pages) )
> +        return -1;
> +
> +    if (dom->allocate)
> +        dom->allocate(dom);
> +
> +    return 0;
>  }
>  
>  int xc_dom_alloc_segment(struct xc_dom_image *dom,

Currently there are three places that call dom->allocate (if we include
the call in the proposed diff). I think it would be better if we push
dom->allocate down to xc_dom_chk_alloc_pages, then refactor
xc_dom_alloc_page to use xc_dom_chk_alloc_pages.

Just some thought after a quick look at the code. I will see what I can
do after confirming this is the culprit.

Wei.