On Mon, Mar 11, 2019 at 02:42:58PM +0100, Paolo Bonzini wrote:
>On 11/03/19 06:42, Wei Yang wrote:
>> 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 <richardw.y...@linux.intel.com>
>>
>> ---
>> 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
>
>The last paragraph is a duplicate of the comments in the function, so it
>can be deleted. I did that and queued the patch.
>
Thanks :-)
>Paolo
>
>> + */
>> 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);
>> }
>> }
>>
>>
--
Wei Yang
Help you, Help me
