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bh=W2xadBhOlctA+eFTSVDngodlBQX81CnvqOgmN6nNNlI=; b=EBmj0Iro/Rc4yihIO50ELRl+eI53qfgTqqov5i2AfQgR8kh+D8qdAUcPWAFJjichH24ues DY79yn2hpHA+V4P8IM5S7f4oyk9yyV4KXoJp4Md1+qbzTSKeiCnLUsokLsNl87rTaBjpQi wvCUBi4k5snlec3ZpPKumsQo8MsfJZA= X-MC-Unique: B8fbtWZVOSeq5oiOymVNqA-1 From: David Hildenbrand To: qemu-devel@nongnu.org Subject: [PATCH v2 2/9] util/mmap-alloc: Factor out calculation of the pagesize for the guard page Date: Fri, 5 Mar 2021 11:16:27 +0100 Message-Id: <20210305101634.10745-3-david@redhat.com> In-Reply-To: <20210305101634.10745-1-david@redhat.com> References: <20210305101634.10745-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=david@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=216.205.24.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juan Quintela , Murilo Opsfelder Araujo , Cornelia Huck , Eduardo Habkost , "Michael S. Tsirkin" , Stefan Weil , David Hildenbrand , Richard Henderson , "Dr. David Alan Gilbert" , Peter Xu , Greg Kurz , Halil Pasic , Christian Borntraeger , Stefan Hajnoczi , Igor Mammedov , Thomas Huth , Paolo Bonzini , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Igor Kotrasinski Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" 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 Acked-by: Murilo Opsfelder Araujo Cc: Igor Kotrasinski Signed-off-by: David Hildenbrand --- 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 e6fa8b598b..24854064b4 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -82,6 +82,16 @@ size_t qemu_mempath_getpagesize(const char *mem_path) return qemu_real_host_page_size; } =20 +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, @@ -90,12 +100,12 @@ void *qemu_ram_mmap(int fd, bool is_pmem, off_t map_offset) { + const size_t guard_pagesize =3D mmap_guard_pagesize(fd); int prot; int flags; int map_sync_flags =3D 0; int guardfd; size_t offset; - size_t pagesize; size_t total; void *guardptr; void *ptr; @@ -116,8 +126,7 @@ void *qemu_ram_mmap(int fd, * anonymous memory is OK. */ flags =3D MAP_PRIVATE; - pagesize =3D qemu_fd_getpagesize(fd); - if (fd =3D=3D -1 || pagesize =3D=3D qemu_real_host_page_size) { + if (fd =3D=3D -1 || guard_pagesize =3D=3D qemu_real_host_page_size) { guardfd =3D -1; flags |=3D MAP_ANONYMOUS; } else { @@ -126,7 +135,6 @@ void *qemu_ram_mmap(int fd, } #else guardfd =3D -1; - pagesize =3D qemu_real_host_page_size; flags =3D MAP_PRIVATE | MAP_ANONYMOUS; #endif =20 @@ -138,7 +146,7 @@ void *qemu_ram_mmap(int fd, =20 assert(is_power_of_2(align)); /* Always align to host page size */ - assert(align >=3D pagesize); + assert(align >=3D guard_pagesize); =20 flags =3D MAP_FIXED; flags |=3D fd =3D=3D -1 ? MAP_ANONYMOUS : 0; @@ -193,8 +201,8 @@ void *qemu_ram_mmap(int fd, * a guard page guarding against potential buffer overflows. */ total -=3D 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); } =20 return ptr; @@ -202,15 +210,8 @@ void *qemu_ram_mmap(int fd, =20 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 =3D qemu_fd_getpagesize(fd); -#else - pagesize =3D qemu_real_host_page_size; -#endif - munmap(ptr, size + pagesize); + munmap(ptr, size + mmap_guard_pagesize(fd)); } } --=20 2.29.2