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authorTyler Hall <tylerwhall@gmail.com>2012-07-25 18:45:04 -0400
committerStefan Hajnoczi <stefanha@linux.vnet.ibm.com>2012-08-03 14:25:22 +0100
commit69b67646bc7ae7f3d28b278e6ae4435a767450ec (patch)
treeac2df7357c0800679fc631de83fc6dffd6e4069a /exec.c
parentadb2a9b5d4d5170f0b58b9f92f816048f6b8932b (diff)
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exec.c: Use subpages for large unaligned mappings
Registering a multi-page memory region that is non-page-aligned results in a subpage from the start to the page boundary, some number of full pages, and possibly another subpage from the last page boundary to the end. The full pages will have a value for offset_within_region that is not a multiple of TARGET_PAGE_SIZE. Accesses through softmmu are unable to handle this and will segfault. Handling full pages through subpages is not optimal, but only non-page-aligned mappings take the penalty. Signed-off-by: Tyler Hall <tylerwhall@gmail.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Avi Kivity <avi@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Diffstat (limited to 'exec.c')
-rw-r--r--exec.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/exec.c b/exec.c
index 27b100c..e6ac3e7 100644
--- a/exec.c
+++ b/exec.c
@@ -2305,10 +2305,15 @@ void cpu_register_physical_memory_log(MemoryRegionSection *section,
remain.offset_within_address_space += now.size;
remain.offset_within_region += now.size;
}
- now = remain;
- now.size &= TARGET_PAGE_MASK;
- if (now.size) {
- register_multipage(&now);
+ while (remain.size >= TARGET_PAGE_SIZE) {
+ now = remain;
+ if (remain.offset_within_region & ~TARGET_PAGE_MASK) {
+ now.size = TARGET_PAGE_SIZE;
+ register_subpage(&now);
+ } else {
+ now.size &= TARGET_PAGE_MASK;
+ register_multipage(&now);
+ }
remain.size -= now.size;
remain.offset_within_address_space += now.size;
remain.offset_within_region += now.size;