Re: [PATCH] Use Little Endian for Dirty Bitmap
On Mon, 2009-07-27 at 12:38 +0200, 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 ag...@suse.de --- 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); } } I don't think I've ever exercised the dirty bitmap code, and I don't really have an opinion. Avi? -- Hollis Blanchard IBM Linux Technology Center -- To unsubscribe from this list: send the line unsubscribe kvm-ppc in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] Use Little Endian for Dirty Bitmap
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 ag...@suse.de --- 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 majord...@vger.kernel.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 majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH] Use Little Endian for Dirty Bitmap
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 ag...@suse.de --- 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-ppc in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
