Re: [Xen-devel] [PATCH] xen/arm: flush dcache after memcpy'ing the kernel image

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2012-12-05 at 18:37 +0000, Stefano Stabellini wrote:
> After memcpy'ing the kernel in guest memory we need to flush the dcache
> to make sure that the data actually reaches the memory before we start
> executing guest code with caches disabled.
> 
> This fixes a boot time bug on the Cortex A15 Versatile Express that
> usually shows up as follow:
> 
> (XEN) Hypervisor Trap. HSR=0x80000006 EC=0x20 IL=0 Syndrome=6
> (XEN) Unexpected Trap: Hypervisor

That's a symptom of a thousand different problems though, since it's
just a generic Instruction Abort from guest mode caused by a translation
fault at stage 2. 

Anyhow this won't apply in top of "arm: support for initial modules
(e.g. dom0) and DTB supplied in RAM", could you rebase on that please?

> Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> ---
>  xen/arch/arm/kernel.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/xen/arch/arm/kernel.c b/xen/arch/arm/kernel.c
> index b4a823d..81818b1 100644
> --- a/xen/arch/arm/kernel.c
> +++ b/xen/arch/arm/kernel.c
> @@ -53,6 +53,7 @@ void copy_from_paddr(void *dst, paddr_t paddr, unsigned 
> long len, int attrindx)
>  
>          set_fixmap(FIXMAP_MISC, p, attrindx);
>          memcpy(dst, src + s, l);
> +        flush_xen_dcache_va_range(dst, l);
>  
>          paddr += l;
>          dst += l;
> @@ -82,6 +83,7 @@ static void kernel_zimage_load(struct kernel_info *info)
>  
>          set_fixmap(FIXMAP_MISC, (flash+offs) >> PAGE_SHIFT, DEV_SHARED);
>          memcpy(dst, src, PAGE_SIZE);
> +        flush_xen_dcache_va_range(dst, PAGE_SIZE);
>          clear_fixmap(FIXMAP_MISC);
>  
>          unmap_domain_page(dst);



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