[Xen-devel] Re: [Xen-changelog] [xen-unstable] tboot: fix tboot memory mapping for 32b

[Mark Johnson <johnson.nh@xxxxxxxxx>]

On Tue, Sep 22, 2009 at 4:25 AM, Xen patchbot-unstable
<patchbot-unstable@xxxxxxxxxxxxxxxxxxx> wrote:
> # HG changeset patch
> # User Keir Fraser <keir.fraser@xxxxxxxxxx>
> # Date 1253605000 -3600
> # Node ID bcb6b95b30b13efa9635f8b8e1b7ff57c50dae3d
> # Parent  be747c582738035889d5f3f9d40051818e1af50e
> tboot: fix tboot memory mapping for 32b
>
> This patch used fixmap to get TXT heap base/size and SINIT base/size
> from TXT pub config registers (whose address starts from 0xfed20000),
> and get DMAR table copy from TXT heap (whose address may start from
> 0x7d520000) for tboot, instead of using map_pages_to_xen(), which will
> cause panic on x86_32.
>
> Signed-off-by: Shane Wang <shane.wang@xxxxxxxxx>
> ---
>  xen/arch/x86/tboot.c         |   94 
> ++++++++++++++++++++++++-------------------
>  xen/include/asm-x86/fixmap.h |    1
>  2 files changed, 54 insertions(+), 41 deletions(-)
>
> diff -r be747c582738 -r bcb6b95b30b1 xen/arch/x86/tboot.c
> --- a/xen/arch/x86/tboot.c      Tue Sep 22 08:28:26 2009 +0100
> +++ b/xen/arch/x86/tboot.c      Tue Sep 22 08:36:40 2009 +0100
> @@ -69,12 +69,29 @@ typedef struct __packed {
>     uint32_t     vtd_dmars_off;
>  } sinit_mle_data_t;
>
> +static void tboot_copy_memory(unsigned char *va, uint32_t size,
> +                              unsigned long pa)
> +{
> +    uint32_t map_base;
> +    unsigned long map_addr;
> +    int i;
> +
> +    map_base = 0;
> +    for (i = 0; i < size; i++) {
> +        if ( map_base != PFN_DOWN(pa + i) ) {
> +            map_base = PFN_DOWN(pa + i);
> +            set_fixmap(FIX_TBOOT_MAP_ADDRESS, map_base << PAGE_SHIFT);
> +            map_addr = (unsigned long)fix_to_virt(FIX_TBOOT_MAP_ADDRESS);
> +        }
> +        *(va + i) = *(unsigned char *)(map_addr + pa + i
> +                                       - (map_base << PAGE_SHIFT));
> +    }
> +}
> +

I see the following error with this change..

tboot.c: In function `tboot_copy_memory':
tboot.c:76: warning: 'map_addr' might be used uninitialized in this function
gmake[5]: *** [tboot.o] Error 1



MRJ

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