Re: [PATCH] Use Little Endian for Dirty Bitmap

[Alexander Graf <agraf-l3A5Bk7waGM@public.gmane.org>]

bump

On 27.07.2009, at 12:38, Alexander Graf wrote:

> We currently use host endian long types to store information
> in the dirty bitmap.
>
> This works reasonably well on Little Endian targets, because the
> u32 after the first contains the next 32 bits. On Big Endian this
> breaks completely though, forcing us to be inventive here.
>
> So Ben suggested to always use Little Endian, which looks reasonable.
>
> We only have dirty bitmap implemented in Little Endian targets so far
> and since PowerPC would be the first Big Endian platform, we can just
> as well switch to Little Endian always with little effort without
> breaking existing targets.
>
> Signed-off-by: Alexander Graf <agraf-l3A5Bk7waGM@public.gmane.org>
> ---
> virt/kvm/kvm_main.c |    5 +++--
> 1 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 17d8688..3482ad1 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -48,6 +48,7 @@
> #include <asm/io.h>
> #include <asm/uaccess.h>
> #include <asm/pgtable.h>
> +#include <asm-generic/bitops/le.h>
>
> #ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
> #include "coalesced_mmio.h"
> @@ -1656,8 +1657,8 @@ void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
> 		unsigned long rel_gfn = gfn - memslot->base_gfn;
>
> 		/* avoid RMW */
> -		if (!test_bit(rel_gfn, memslot->dirty_bitmap))
> -			set_bit(rel_gfn, memslot->dirty_bitmap);
> +		if (!generic_test_le_bit(rel_gfn, memslot->dirty_bitmap))
> +			generic___set_le_bit(rel_gfn, memslot->dirty_bitmap);
> 	}
> }
>
> -- 
> 1.6.0.2
>
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

--
To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html