Re: [PATCH v2 2/4] libxc: print more error messages when failed

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 29/05/15 12:37, Wei Liu wrote:
> No functional changes introduced.
>
> Signed-off-by: Wei Liu <wei.liu2@citrix.com>
> Cc: Ian Campbell <ian.campbell@citrix.com>
> Cc: Ian Jackson <ian.jackson@eu.citrix.com>

This patch reminds me of a todo item I have wanted to do for a while
using setvcpucontext rather than mapping gfn 0 and manually inserting
`jmp $0x100000`

However, as for the change itself, a definite improvement.

> ---
>  tools/libxc/xc_hvm_build_x86.c | 30 +++++++++++++++++++++++++++---
>  1 file changed, 27 insertions(+), 3 deletions(-)
>
> diff --git a/tools/libxc/xc_hvm_build_x86.c b/tools/libxc/xc_hvm_build_x86.c
> index 92422bf..df4b7ed 100644
> --- a/tools/libxc/xc_hvm_build_x86.c
> +++ b/tools/libxc/xc_hvm_build_x86.c
> @@ -259,7 +259,10 @@ static int setup_guest(xc_interface *xch,
>  
>      memset(&elf, 0, sizeof(elf));
>      if ( elf_init(&elf, image, image_size) != 0 )
> +    {
> +        PERROR("Could not initialise ELF image");
>          goto error_out;
> +    }
>  
>      xc_elf_set_logfile(xch, &elf, 1);
>  
> @@ -522,15 +525,24 @@ static int setup_guest(xc_interface *xch,
>      DPRINTF("  1GB PAGES: 0x%016lx\n", stat_1gb_pages);
>      
>      if ( loadelfimage(xch, &elf, dom, page_array) != 0 )
> +    {
> +        PERROR("Could not load ELF image");
>          goto error_out;
> +    }
>  
>      if ( loadmodules(xch, args, m_start, m_end, dom, page_array) != 0 )
> -        goto error_out;    
> +    {
> +        PERROR("Could not load ACPI modules");
> +        goto error_out;
> +    }
>  
>      if ( (hvm_info_page = xc_map_foreign_range(
>                xch, dom, PAGE_SIZE, PROT_READ | PROT_WRITE,
>                HVM_INFO_PFN)) == NULL )
> +    {
> +        PERROR("Could not map hvm info page");
>          goto error_out;
> +    }
>      build_hvm_info(hvm_info_page, args);
>      munmap(hvm_info_page, PAGE_SIZE);
>  
> @@ -547,7 +559,10 @@ static int setup_guest(xc_interface *xch,
>      }
>  
>      if ( xc_clear_domain_pages(xch, dom, special_pfn(0), NR_SPECIAL_PAGES) )
> -            goto error_out;
> +    {
> +        PERROR("Could not clear special pages");
> +        goto error_out;
> +    }
>  
>      xc_hvm_param_set(xch, dom, HVM_PARAM_STORE_PFN,
>                       special_pfn(SPECIALPAGE_XENSTORE));
> @@ -580,7 +595,10 @@ static int setup_guest(xc_interface *xch,
>      }
>  
>      if ( xc_clear_domain_pages(xch, dom, ioreq_server_pfn(0), NR_IOREQ_SERVER_PAGES) )
> -            goto error_out;
> +    {
> +        PERROR("Could not clear ioreq page");
> +        goto error_out;
> +    }
>  
>      /* Tell the domain where the pages are and how many there are */
>      xc_hvm_param_set(xch, dom, HVM_PARAM_IOREQ_SERVER_PFN,
> @@ -595,7 +613,10 @@ static int setup_guest(xc_interface *xch,
>      if ( (ident_pt = xc_map_foreign_range(
>                xch, dom, PAGE_SIZE, PROT_READ | PROT_WRITE,
>                special_pfn(SPECIALPAGE_IDENT_PT))) == NULL )
> +    {
> +        PERROR("Could not map special page ident_pt");
>          goto error_out;
> +    }
>      for ( i = 0; i < PAGE_SIZE / sizeof(*ident_pt); i++ )
>          ident_pt[i] = ((i << 22) | _PAGE_PRESENT | _PAGE_RW | _PAGE_USER |
>                         _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_PSE);
> @@ -610,7 +631,10 @@ static int setup_guest(xc_interface *xch,
>          char *page0 = xc_map_foreign_range(
>              xch, dom, PAGE_SIZE, PROT_READ | PROT_WRITE, 0);
>          if ( page0 == NULL )
> +        {
> +            PERROR("Could not map page0");
>              goto error_out;
> +        }
>          page0[0] = 0xe9;
>          *(uint32_t *)&page0[1] = entry_eip - 5;
>          munmap(page0, PAGE_SIZE);