| Message ID | 20200305142945.216465-8-david@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Ram blocks with resizeable anonymous allocations under POSIX | expand |
On Thursday, March 5, 2020 11:29:37 AM -03 David Hildenbrand wrote: > Let's factor out calculating the size of the guard page and rename the > variable to make it clearer that this pagesize only applies to the > guard page. > > Reviewed-by: Peter Xu <peterx@redhat.com> > Cc: "Michael S. Tsirkin" <mst@redhat.com> > Cc: Murilo Opsfelder Araujo <muriloo@linux.ibm.com> > Cc: Greg Kurz <groug@kaod.org> > Cc: Eduardo Habkost <ehabkost@redhat.com> > Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > Cc: Igor Mammedov <imammedo@redhat.com> > Signed-off-by: David Hildenbrand <david@redhat.com> > --- Acked-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com> > util/mmap-alloc.c | 31 ++++++++++++++++--------------- > 1 file changed, 16 insertions(+), 15 deletions(-) > > diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c > index 27dcccd8ec..f0277f9fad 100644 > --- a/util/mmap-alloc.c > +++ b/util/mmap-alloc.c > @@ -82,17 +82,27 @@ size_t qemu_mempath_getpagesize(const char *mem_path) > return qemu_real_host_page_size; > } > > +static inline size_t mmap_guard_pagesize(int fd) > +{ > +#if defined(__powerpc64__) && defined(__linux__) > + /* Mappings in the same segment must share the same page size */ > + return qemu_fd_getpagesize(fd); > +#else > + return qemu_real_host_page_size; > +#endif > +} > + > void *qemu_ram_mmap(int fd, > size_t size, > size_t align, > bool shared, > bool is_pmem) > { > + const size_t guard_pagesize = mmap_guard_pagesize(fd); > int flags; > int map_sync_flags = 0; > int guardfd; > size_t offset; > - size_t pagesize; > size_t total; > void *guardptr; > void *ptr; > @@ -113,8 +123,7 @@ void *qemu_ram_mmap(int fd, > * anonymous memory is OK. > */ > flags = MAP_PRIVATE; > - pagesize = qemu_fd_getpagesize(fd); > - if (fd == -1 || pagesize == qemu_real_host_page_size) { > + if (fd == -1 || guard_pagesize == qemu_real_host_page_size) { > guardfd = -1; > flags |= MAP_ANONYMOUS; > } else { > @@ -123,7 +132,6 @@ void *qemu_ram_mmap(int fd, > } > #else > guardfd = -1; > - pagesize = qemu_real_host_page_size; > flags = MAP_PRIVATE | MAP_ANONYMOUS; > #endif > > @@ -135,7 +143,7 @@ void *qemu_ram_mmap(int fd, > > assert(is_power_of_2(align)); > /* Always align to host page size */ > - assert(align >= pagesize); > + assert(align >= guard_pagesize); > > flags = MAP_FIXED; > flags |= fd == -1 ? MAP_ANONYMOUS : 0; > @@ -189,8 +197,8 @@ void *qemu_ram_mmap(int fd, > * a guard page guarding against potential buffer overflows. > */ > total -= offset; > - if (total > size + pagesize) { > - munmap(ptr + size + pagesize, total - size - pagesize); > + if (total > size + guard_pagesize) { > + munmap(ptr + size + guard_pagesize, total - size - guard_pagesize); > } > > return ptr; > @@ -198,15 +206,8 @@ void *qemu_ram_mmap(int fd, > > void qemu_ram_munmap(int fd, void *ptr, size_t size) > { > - size_t pagesize; > - > if (ptr) { > /* Unmap both the RAM block and the guard page */ > -#if defined(__powerpc64__) && defined(__linux__) > - pagesize = qemu_fd_getpagesize(fd); > -#else > - pagesize = qemu_real_host_page_size; > -#endif > - munmap(ptr, size + pagesize); > + munmap(ptr, size + mmap_guard_pagesize(fd)); > } > } -- Murilo
diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c index 27dcccd8ec..f0277f9fad 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -82,17 +82,27 @@ size_t qemu_mempath_getpagesize(const char *mem_path) return qemu_real_host_page_size; } +static inline size_t mmap_guard_pagesize(int fd) +{ +#if defined(__powerpc64__) && defined(__linux__) + /* Mappings in the same segment must share the same page size */ + return qemu_fd_getpagesize(fd); +#else + return qemu_real_host_page_size; +#endif +} + void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared, bool is_pmem) { + const size_t guard_pagesize = mmap_guard_pagesize(fd); int flags; int map_sync_flags = 0; int guardfd; size_t offset; - size_t pagesize; size_t total; void *guardptr; void *ptr; @@ -113,8 +123,7 @@ void *qemu_ram_mmap(int fd, * anonymous memory is OK. */ flags = MAP_PRIVATE; - pagesize = qemu_fd_getpagesize(fd); - if (fd == -1 || pagesize == qemu_real_host_page_size) { + if (fd == -1 || guard_pagesize == qemu_real_host_page_size) { guardfd = -1; flags |= MAP_ANONYMOUS; } else { @@ -123,7 +132,6 @@ void *qemu_ram_mmap(int fd, } #else guardfd = -1; - pagesize = qemu_real_host_page_size; flags = MAP_PRIVATE | MAP_ANONYMOUS; #endif @@ -135,7 +143,7 @@ void *qemu_ram_mmap(int fd, assert(is_power_of_2(align)); /* Always align to host page size */ - assert(align >= pagesize); + assert(align >= guard_pagesize); flags = MAP_FIXED; flags |= fd == -1 ? MAP_ANONYMOUS : 0; @@ -189,8 +197,8 @@ void *qemu_ram_mmap(int fd, * a guard page guarding against potential buffer overflows. */ total -= offset; - if (total > size + pagesize) { - munmap(ptr + size + pagesize, total - size - pagesize); + if (total > size + guard_pagesize) { + munmap(ptr + size + guard_pagesize, total - size - guard_pagesize); } return ptr; @@ -198,15 +206,8 @@ void *qemu_ram_mmap(int fd, void qemu_ram_munmap(int fd, void *ptr, size_t size) { - size_t pagesize; - if (ptr) { /* Unmap both the RAM block and the guard page */ -#if defined(__powerpc64__) && defined(__linux__) - pagesize = qemu_fd_getpagesize(fd); -#else - pagesize = qemu_real_host_page_size; -#endif - munmap(ptr, size + pagesize); + munmap(ptr, size + mmap_guard_pagesize(fd)); } }