From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:32793) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h3Die-0006Xr-LS for qemu-devel@nongnu.org; Mon, 11 Mar 2019 01:43:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1h3Dib-0004hy-J1 for qemu-devel@nongnu.org; Mon, 11 Mar 2019 01:43:24 -0400 Received: from mga07.intel.com ([134.134.136.100]:33679) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1h3Dib-0004gU-7T for qemu-devel@nongnu.org; Mon, 11 Mar 2019 01:43:21 -0400 From: Wei Yang Date: Mon, 11 Mar 2019 13:42:52 +0800 Message-Id: <20190311054252.6094-1-richardw.yang@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [Qemu-devel] [PATCH v3] exec.c: refactor function flatview_add_to_dispatch() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: rth@twiddle.net, pbonzini@redhat.com, Wei Yang 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 --- v3: * pass int128_make64() instead of 0 to int128_gt() 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..79cd561b3b 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_index); } +/* + * 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 = *section, remain = *section; + MemoryRegionSection now, remain = *section; Int128 page_size = int128_make64(TARGET_PAGE_SIZE); - if (now.offset_within_address_space & ~TARGET_PAGE_MASK) { - uint64_t left = TARGET_PAGE_ALIGN(now.offset_within_address_space) - - now.offset_within_address_space; + /* register first subpage */ + if (remain.offset_within_address_space & ~TARGET_PAGE_MASK) { + uint64_t left = TARGET_PAGE_ALIGN(remain.offset_within_address_space) + - remain.offset_within_address_space; + now = remain; now.size = int128_min(int128_make64(left), now.size); + remain.size = int128_sub(remain.size, now.size); + remain.offset_within_address_space += int128_get64(now.size); + remain.offset_within_region += int128_get64(now.size); register_subpage(fv, &now); - } else { - now.size = int128_zero(); } - while (int128_ne(remain.size, now.size)) { + + /* register page */ + if (int128_ge(remain.size, page_size)) { + now = remain; + now.size = int128_and(now.size, int128_neg(page_size)); remain.size = int128_sub(remain.size, now.size); remain.offset_within_address_space += int128_get64(now.size); remain.offset_within_region += int128_get64(now.size); - now = remain; - if (int128_lt(remain.size, page_size)) { - register_subpage(fv, &now); - } else if (remain.offset_within_address_space & ~TARGET_PAGE_MASK) { - now.size = page_size; - register_subpage(fv, &now); - } else { - now.size = int128_and(now.size, int128_neg(page_size)); - register_multipage(fv, &now); - } + register_multipage(fv, &now); + } + + /* register last subpage */ + if (int128_gt(remain.size, int128_make64(0))) { + register_subpage(fv, &remain); } } -- 2.19.1