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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 30 Jan 2019 23:36:52 -0000 Received: from b03ledav005.gho.boulder.ibm.com (b03ledav005.gho.boulder.ibm.com [9.17.130.236]) by b03cxnp08028.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x0UNao2s24641602 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 30 Jan 2019 23:36:50 GMT Received: from b03ledav005.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C8B5CBE059; Wed, 30 Jan 2019 23:36:50 +0000 (GMT) Received: from b03ledav005.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 648D4BE04F; Wed, 30 Jan 2019 23:36:46 +0000 (GMT) Received: from kermit-br-ibm-com.ibmmodules.com (unknown [9.80.91.43]) by b03ledav005.gho.boulder.ibm.com (Postfix) with ESMTP; Wed, 30 Jan 2019 23:36:46 +0000 (GMT) From: Murilo Opsfelder Araujo To: qemu-devel@nongnu.org, qemu-ppc@nongnu.org Date: Wed, 30 Jan 2019 21:36:05 -0200 X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190130233605.22163-1-muriloo@linux.ibm.com> References: <20190130233605.22163-1-muriloo@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 x-cbid: 19013023-0012-0000-0000-000017025DEC X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00010506; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000277; SDB=6.01154131; UDB=6.00601769; IPR=6.00934507; MB=3.00025361; MTD=3.00000008; XFM=3.00000015; UTC=2019-01-30 23:36:55 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19013023-0013-0000-0000-000056051312 Message-Id: <20190130233605.22163-3-muriloo@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-01-30_18:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=2 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1901300168 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] [fuzzy] X-Received-From: 148.163.158.5 Subject: [Qemu-devel] [PATCH 2/2] mmap-alloc: fix hugetlbfs misaligned length in ppc64 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Crosthwaite , Fabiano Rosas , "Michael S . Tsirkin" , Greg Kurz , Cao jin , mopsfelder@gmail.com, Murilo Opsfelder Araujo , Paolo Bonzini , Richard Henderson , David Gibson Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP The commit 7197fb4058bcb68986bae2bb2c04d6370f3e7218 ("util/mmap-alloc: fix hugetlb support on ppc64") fixed Huge TLB mappings on ppc64. However, we still need to consider the underlying huge page size during munmap() because it requires that both address and length be a multiple of the underlying huge page size for Huge TLB mappings. Quote from "Huge page (Huge TLB) mappings" paragraph under NOTES section of the munmap(2) manual: "For munmap(), addr and length must both be a multiple of the underlying huge page size." On ppc64, the munmap() in qemu_ram_munmap() does not work for Huge TLB mappings because the mapped segment can be aligned with the underlying huge page size, not aligned with the native system page size, as returned by getpagesize(). This has the side effect of not releasing huge pages back to the pool after a hugetlbfs file-backed memory device is hot-unplugged. This patch fixes the situation in qemu_ram_mmap() and qemu_ram_munmap() by considering the underlying page size on ppc64. After this patch, memory hot-unplug releases huge pages back to the pool. Fixes: 7197fb4058bcb68986bae2bb2c04d6370f3e7218 Signed-off-by: Murilo Opsfelder Araujo Reviewed-by: Greg Kurz Reported-by: Balamuruhan S Tested-by: Balamuruhan S --- exec.c | 4 ++-- include/qemu/mmap-alloc.h | 2 +- util/mmap-alloc.c | 22 ++++++++++++++++------ util/oslib-posix.c | 2 +- 4 files changed, 20 insertions(+), 10 deletions(-) diff --git a/exec.c b/exec.c index da3e635f91..0db6d8bf34 100644 --- a/exec.c +++ b/exec.c @@ -1871,7 +1871,7 @@ static void *file_ram_alloc(RAMBlock *block, if (mem_prealloc) { os_mem_prealloc(fd, area, memory, smp_cpus, errp); if (errp && *errp) { - qemu_ram_munmap(area, memory); + qemu_ram_munmap(fd, area, memory); return NULL; } } @@ -2392,7 +2392,7 @@ static void reclaim_ramblock(RAMBlock *block) xen_invalidate_map_cache_entry(block->host); #ifndef _WIN32 } else if (block->fd >= 0) { - qemu_ram_munmap(block->host, block->max_length); + qemu_ram_munmap(block->fd, block->host, block->max_length); close(block->fd); #endif } else { diff --git a/include/qemu/mmap-alloc.h b/include/qemu/mmap-alloc.h index 50385e3f81..ef04f0ed5b 100644 --- a/include/qemu/mmap-alloc.h +++ b/include/qemu/mmap-alloc.h @@ -9,6 +9,6 @@ size_t qemu_mempath_getpagesize(const char *mem_path); void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared); -void qemu_ram_munmap(void *ptr, size_t size); +void qemu_ram_munmap(int fd, void *ptr, size_t size); #endif diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c index f71ea038c8..8565885420 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -80,6 +80,7 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) int flags; int guardfd; size_t offset; + size_t pagesize; size_t total; void *guardptr; void *ptr; @@ -100,7 +101,8 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) * anonymous memory is OK. */ flags = MAP_PRIVATE; - if (fd == -1 || qemu_fd_getpagesize(fd) == getpagesize()) { + pagesize = qemu_fd_getpagesize(fd); + if (fd == -1 || pagesize == getpagesize()) { guardfd = -1; flags |= MAP_ANONYMOUS; } else { @@ -109,6 +111,7 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) } #else guardfd = -1; + pagesize = getpagesize(); flags = MAP_PRIVATE | MAP_ANONYMOUS; #endif @@ -120,7 +123,7 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) assert(is_power_of_2(align)); /* Always align to host page size */ - assert(align >= getpagesize()); + assert(align >= pagesize); flags = MAP_FIXED; flags |= fd == -1 ? MAP_ANONYMOUS : 0; @@ -143,17 +146,24 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) * a guard page guarding against potential buffer overflows. */ total -= offset; - if (total > size + getpagesize()) { - munmap(ptr + size + getpagesize(), total - size - getpagesize()); + if (total > size + pagesize) { + munmap(ptr + size + pagesize, total - size - pagesize); } return ptr; } -void qemu_ram_munmap(void *ptr, size_t size) +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 */ - munmap(ptr, size + getpagesize()); +#if defined(__powerpc64__) && defined(__linux__) + pagesize = qemu_fd_getpagesize(fd); +#else + pagesize = getpagesize(); +#endif + munmap(ptr, size + pagesize); } } diff --git a/util/oslib-posix.c b/util/oslib-posix.c index 4ce1ba9ca4..37c5854b9c 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -226,7 +226,7 @@ void qemu_vfree(void *ptr) void qemu_anon_ram_free(void *ptr, size_t size) { trace_qemu_anon_ram_free(ptr, size); - qemu_ram_munmap(ptr, size); + qemu_ram_munmap(-1, ptr, size); } void qemu_set_block(int fd)