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X-Received-From: 134.134.136.126 Subject: [Qemu-devel] [PATCH v2] exec.c: refactor function flatview_add_to_dispatch() X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: pbonzini@redhat.com, Wei Yang , rth@twiddle.net Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" flatview_add_to_dispatch() registers page based on the condition of *section*, which may looks like this: |s|PPPPPPP|s| where s stands for subpage and P for page. The procedure of this function could be described as: - register first subpage - register page - register last subpage This means the procedure could be simplified into these three steps instead of a loop iteration. This patch refactors the function into three corresponding steps and adds some comment to clarify it. Signed-off-by: Wei Yang --- v2: * removes the loop iteration as suggested by Paolo --- exec.c | 50 +++++++++++++++++++++++++++++++++----------------- 1 file changed, 33 insertions(+), 17 deletions(-) diff --git a/exec.c b/exec.c index 0959b00c06..160b8587d4 100644 --- a/exec.c +++ b/exec.c @@ -1598,34 +1598,50 @@ static void register_multipage(FlatView *fv, phys_page_set(d, start_addr >> TARGET_PAGE_BITS, num_pages, section_in= dex); } =20 +/* + * The range in *section* may look like this: + * + * |s|PPPPPPP|s| + * + * where s stands for subpage and P for page. + * + * The procedure in following function could be described as: + * + * - register first subpage + * - register page + * - register last subpage + */ void flatview_add_to_dispatch(FlatView *fv, MemoryRegionSection *section) { - MemoryRegionSection now =3D *section, remain =3D *section; + MemoryRegionSection now, remain =3D *section; Int128 page_size =3D int128_make64(TARGET_PAGE_SIZE); =20 - if (now.offset_within_address_space & ~TARGET_PAGE_MASK) { - uint64_t left =3D TARGET_PAGE_ALIGN(now.offset_within_address_spac= e) - - now.offset_within_address_space; + /* register first subpage */ + if (remain.offset_within_address_space & ~TARGET_PAGE_MASK) { + uint64_t left =3D TARGET_PAGE_ALIGN(remain.offset_within_address_s= pace) + - remain.offset_within_address_space; =20 + now =3D remain; now.size =3D int128_min(int128_make64(left), now.size); + remain.size =3D int128_sub(remain.size, now.size); + remain.offset_within_address_space +=3D int128_get64(now.size); + remain.offset_within_region +=3D int128_get64(now.size); register_subpage(fv, &now); - } else { - now.size =3D int128_zero(); } - while (int128_ne(remain.size, now.size)) { + + /* register page */ + if (int128_ge(remain.size, page_size)) { + now =3D remain; + now.size =3D int128_and(now.size, int128_neg(page_size)); remain.size =3D int128_sub(remain.size, now.size); remain.offset_within_address_space +=3D int128_get64(now.size); remain.offset_within_region +=3D int128_get64(now.size); - now =3D remain; - if (int128_lt(remain.size, page_size)) { - register_subpage(fv, &now); - } else if (remain.offset_within_address_space & ~TARGET_PAGE_MASK)= { - now.size =3D page_size; - register_subpage(fv, &now); - } else { - now.size =3D int128_and(now.size, int128_neg(page_size)); - register_multipage(fv, &now); - } + register_multipage(fv, &now); + } + + /* register last subpage */ + if (int128_gt(remain.size, 0)) { + register_subpage(fv, &remain); } } =20 --=20 2.19.1