| Message ID | 20190130233605.22163-2-muriloo@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mmap-alloc: fix hugetlbfs misaligned length in ppc64 | expand |
On Wed, 30 Jan 2019 21:36:04 -0200 Murilo Opsfelder Araujo <muriloo@linux.ibm.com> wrote: > Unfold parts of qemu_ram_mmap() for the sake of understanding, moving > declarations to the top, and keeping architecture-specifics in the > ifdef-else blocks. No changes in the function behaviour. > > Give ptr and ptr1 meaningful names: > ptr -> guardptr : pointer to the PROT_NONE guard region > ptr1 -> ptr : pointer to the mapped memory returned to caller > > Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com> > --- Reviewed-by: Greg Kurz <groug@kaod.org> > util/mmap-alloc.c | 53 ++++++++++++++++++++++++++++++----------------- > 1 file changed, 34 insertions(+), 19 deletions(-) > > diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c > index fd329eccd8..f71ea038c8 100644 > --- a/util/mmap-alloc.c > +++ b/util/mmap-alloc.c > @@ -77,11 +77,19 @@ size_t qemu_mempath_getpagesize(const char *mem_path) > > void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) > { > + int flags; > + int guardfd; > + size_t offset; > + size_t total; > + void *guardptr; > + void *ptr; > + > /* > * Note: this always allocates at least one extra page of virtual address > * space, even if size is already aligned. > */ > - size_t total = size + align; > + total = size + align; > + > #if defined(__powerpc64__) && defined(__linux__) > /* On ppc64 mappings in the same segment (aka slice) must share the same > * page size. Since we will be re-allocating part of this segment > @@ -91,16 +99,22 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) > * We do this unless we are using the system page size, in which case > * anonymous memory is OK. > */ > - int anonfd = fd == -1 || qemu_fd_getpagesize(fd) == getpagesize() ? -1 : fd; > - int flags = anonfd == -1 ? MAP_ANONYMOUS : MAP_NORESERVE; > - void *ptr = mmap(0, total, PROT_NONE, flags | MAP_PRIVATE, anonfd, 0); > + flags = MAP_PRIVATE; > + if (fd == -1 || qemu_fd_getpagesize(fd) == getpagesize()) { > + guardfd = -1; > + flags |= MAP_ANONYMOUS; > + } else { > + guardfd = fd; > + flags |= MAP_NORESERVE; > + } > #else > - void *ptr = mmap(0, total, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); > + guardfd = -1; > + flags = MAP_PRIVATE | MAP_ANONYMOUS; > #endif > - size_t offset; > - void *ptr1; > > - if (ptr == MAP_FAILED) { > + guardptr = mmap(0, total, PROT_NONE, flags, guardfd, 0); > + > + if (guardptr == MAP_FAILED) { > return MAP_FAILED; > } > > @@ -108,19 +122,20 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) > /* Always align to host page size */ > assert(align >= getpagesize()); > > - offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr; > - ptr1 = mmap(ptr + offset, size, PROT_READ | PROT_WRITE, > - MAP_FIXED | > - (fd == -1 ? MAP_ANONYMOUS : 0) | > - (shared ? MAP_SHARED : MAP_PRIVATE), > - fd, 0); > - if (ptr1 == MAP_FAILED) { > - munmap(ptr, total); > + flags = MAP_FIXED; > + flags |= fd == -1 ? MAP_ANONYMOUS : 0; > + flags |= shared ? MAP_SHARED : MAP_PRIVATE; > + offset = QEMU_ALIGN_UP((uintptr_t)guardptr, align) - (uintptr_t)guardptr; > + > + ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE, flags, fd, 0); > + > + if (ptr == MAP_FAILED) { > + munmap(guardptr, total); > return MAP_FAILED; > } > > if (offset > 0) { > - munmap(ptr, offset); > + munmap(guardptr, offset); > } > > /* > @@ -129,10 +144,10 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) > */ > total -= offset; > if (total > size + getpagesize()) { > - munmap(ptr1 + size + getpagesize(), total - size - getpagesize()); > + munmap(ptr + size + getpagesize(), total - size - getpagesize()); > } > > - return ptr1; > + return ptr; > } > > void qemu_ram_munmap(void *ptr, size_t size)
On Wed, Jan 30, 2019 at 09:36:04PM -0200, Murilo Opsfelder Araujo wrote: > Unfold parts of qemu_ram_mmap() for the sake of understanding, moving > declarations to the top, and keeping architecture-specifics in the > ifdef-else blocks. No changes in the function behaviour. > > Give ptr and ptr1 meaningful names: > ptr -> guardptr : pointer to the PROT_NONE guard region > ptr1 -> ptr : pointer to the mapped memory returned to caller > > Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com> Reported-by: Balamuruhan S <bala24@linux.vnet.ibm.com> Tested-by: Balamuruhan S <bala24@linux.vnet.ibm.com> > --- > util/mmap-alloc.c | 53 ++++++++++++++++++++++++++++++----------------- > 1 file changed, 34 insertions(+), 19 deletions(-) > > diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c > index fd329eccd8..f71ea038c8 100644 > --- a/util/mmap-alloc.c > +++ b/util/mmap-alloc.c > @@ -77,11 +77,19 @@ size_t qemu_mempath_getpagesize(const char *mem_path) > > void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) > { > + int flags; > + int guardfd; > + size_t offset; > + size_t total; > + void *guardptr; > + void *ptr; > + > /* > * Note: this always allocates at least one extra page of virtual address > * space, even if size is already aligned. > */ > - size_t total = size + align; > + total = size + align; > + > #if defined(__powerpc64__) && defined(__linux__) > /* On ppc64 mappings in the same segment (aka slice) must share the same > * page size. Since we will be re-allocating part of this segment > @@ -91,16 +99,22 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) > * We do this unless we are using the system page size, in which case > * anonymous memory is OK. > */ > - int anonfd = fd == -1 || qemu_fd_getpagesize(fd) == getpagesize() ? -1 : fd; > - int flags = anonfd == -1 ? MAP_ANONYMOUS : MAP_NORESERVE; > - void *ptr = mmap(0, total, PROT_NONE, flags | MAP_PRIVATE, anonfd, 0); > + flags = MAP_PRIVATE; > + if (fd == -1 || qemu_fd_getpagesize(fd) == getpagesize()) { > + guardfd = -1; > + flags |= MAP_ANONYMOUS; > + } else { > + guardfd = fd; > + flags |= MAP_NORESERVE; > + } > #else > - void *ptr = mmap(0, total, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); > + guardfd = -1; > + flags = MAP_PRIVATE | MAP_ANONYMOUS; > #endif > - size_t offset; > - void *ptr1; > > - if (ptr == MAP_FAILED) { > + guardptr = mmap(0, total, PROT_NONE, flags, guardfd, 0); > + > + if (guardptr == MAP_FAILED) { > return MAP_FAILED; > } > > @@ -108,19 +122,20 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) > /* Always align to host page size */ > assert(align >= getpagesize()); > > - offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr; > - ptr1 = mmap(ptr + offset, size, PROT_READ | PROT_WRITE, > - MAP_FIXED | > - (fd == -1 ? MAP_ANONYMOUS : 0) | > - (shared ? MAP_SHARED : MAP_PRIVATE), > - fd, 0); > - if (ptr1 == MAP_FAILED) { > - munmap(ptr, total); > + flags = MAP_FIXED; > + flags |= fd == -1 ? MAP_ANONYMOUS : 0; > + flags |= shared ? MAP_SHARED : MAP_PRIVATE; > + offset = QEMU_ALIGN_UP((uintptr_t)guardptr, align) - (uintptr_t)guardptr; > + > + ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE, flags, fd, 0); > + > + if (ptr == MAP_FAILED) { > + munmap(guardptr, total); > return MAP_FAILED; > } > > if (offset > 0) { > - munmap(ptr, offset); > + munmap(guardptr, offset); > } > > /* > @@ -129,10 +144,10 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) > */ > total -= offset; > if (total > size + getpagesize()) { > - munmap(ptr1 + size + getpagesize(), total - size - getpagesize()); > + munmap(ptr + size + getpagesize(), total - size - getpagesize()); > } > > - return ptr1; > + return ptr; > } > > void qemu_ram_munmap(void *ptr, size_t size) > -- > 2.20.1 > >
diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c index fd329eccd8..f71ea038c8 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -77,11 +77,19 @@ size_t qemu_mempath_getpagesize(const char *mem_path) void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) { + int flags; + int guardfd; + size_t offset; + size_t total; + void *guardptr; + void *ptr; + /* * Note: this always allocates at least one extra page of virtual address * space, even if size is already aligned. */ - size_t total = size + align; + total = size + align; + #if defined(__powerpc64__) && defined(__linux__) /* On ppc64 mappings in the same segment (aka slice) must share the same * page size. Since we will be re-allocating part of this segment @@ -91,16 +99,22 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) * We do this unless we are using the system page size, in which case * anonymous memory is OK. */ - int anonfd = fd == -1 || qemu_fd_getpagesize(fd) == getpagesize() ? -1 : fd; - int flags = anonfd == -1 ? MAP_ANONYMOUS : MAP_NORESERVE; - void *ptr = mmap(0, total, PROT_NONE, flags | MAP_PRIVATE, anonfd, 0); + flags = MAP_PRIVATE; + if (fd == -1 || qemu_fd_getpagesize(fd) == getpagesize()) { + guardfd = -1; + flags |= MAP_ANONYMOUS; + } else { + guardfd = fd; + flags |= MAP_NORESERVE; + } #else - void *ptr = mmap(0, total, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + guardfd = -1; + flags = MAP_PRIVATE | MAP_ANONYMOUS; #endif - size_t offset; - void *ptr1; - if (ptr == MAP_FAILED) { + guardptr = mmap(0, total, PROT_NONE, flags, guardfd, 0); + + if (guardptr == MAP_FAILED) { return MAP_FAILED; } @@ -108,19 +122,20 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) /* Always align to host page size */ assert(align >= getpagesize()); - offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr; - ptr1 = mmap(ptr + offset, size, PROT_READ | PROT_WRITE, - MAP_FIXED | - (fd == -1 ? MAP_ANONYMOUS : 0) | - (shared ? MAP_SHARED : MAP_PRIVATE), - fd, 0); - if (ptr1 == MAP_FAILED) { - munmap(ptr, total); + flags = MAP_FIXED; + flags |= fd == -1 ? MAP_ANONYMOUS : 0; + flags |= shared ? MAP_SHARED : MAP_PRIVATE; + offset = QEMU_ALIGN_UP((uintptr_t)guardptr, align) - (uintptr_t)guardptr; + + ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE, flags, fd, 0); + + if (ptr == MAP_FAILED) { + munmap(guardptr, total); return MAP_FAILED; } if (offset > 0) { - munmap(ptr, offset); + munmap(guardptr, offset); } /* @@ -129,10 +144,10 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) */ total -= offset; if (total > size + getpagesize()) { - munmap(ptr1 + size + getpagesize(), total - size - getpagesize()); + munmap(ptr + size + getpagesize(), total - size - getpagesize()); } - return ptr1; + return ptr; } void qemu_ram_munmap(void *ptr, size_t size)
Unfold parts of qemu_ram_mmap() for the sake of understanding, moving declarations to the top, and keeping architecture-specifics in the ifdef-else blocks. No changes in the function behaviour. Give ptr and ptr1 meaningful names: ptr -> guardptr : pointer to the PROT_NONE guard region ptr1 -> ptr : pointer to the mapped memory returned to caller Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com> --- util/mmap-alloc.c | 53 ++++++++++++++++++++++++++++++----------------- 1 file changed, 34 insertions(+), 19 deletions(-)