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Fri, 04 Apr 2025 02:19:27 +0000 (GMT) Received: from pps.filterd (iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 5340dfDs017355; Fri, 4 Apr 2025 02:19:26 GMT Received: from pps.reinject (localhost [127.0.0.1]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 45t2pspjc8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 04 Apr 2025 02:19:26 +0000 Received: from iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 5342H8gq030074; Fri, 4 Apr 2025 02:19:25 GMT Received: from localhost.localdomain (ca-dev60.us.oracle.com [10.129.136.27]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTP id 45t2pspj73-9; Fri, 04 Apr 2025 02:19:25 +0000 From: Anthony Yznaga To: akpm@linux-foundation.org, willy@infradead.org, markhemm@googlemail.com, viro@zeniv.linux.org.uk, david@redhat.com, khalid@kernel.org Cc: anthony.yznaga@oracle.com, andreyknvl@gmail.com, dave.hansen@intel.com, luto@kernel.org, brauner@kernel.org, arnd@arndb.de, ebiederm@xmission.com, catalin.marinas@arm.com, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhiramat@kernel.org, rostedt@goodmis.org, vasily.averin@linux.dev, xhao@linux.alibaba.com, pcc@google.com, neilb@suse.de, maz@kernel.org Subject: [PATCH v2 08/20] mm/mshare: flush all TLBs when updating PTEs in an mshare range Date: Thu, 3 Apr 2025 19:18:50 -0700 Message-ID: <20250404021902.48863-9-anthony.yznaga@oracle.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20250404021902.48863-1-anthony.yznaga@oracle.com> References: <20250404021902.48863-1-anthony.yznaga@oracle.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1095,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-04-04_01,2025-04-03_03,2024-11-22_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 bulkscore=0 mlxscore=0 spamscore=0 adultscore=0 suspectscore=0 mlxlogscore=999 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2502280000 definitions=main-2504040014 X-Proofpoint-ORIG-GUID: x_lMRsGn6qiH95awEN80uSxpY_3-EKKe X-Proofpoint-GUID: x_lMRsGn6qiH95awEN80uSxpY_3-EKKe Content-Type: text/plain; charset="utf-8" Unlike the mm of a task, an mshare host mm is not updated on context switch. In particular this means that mm_cpumask is never updated which results in TLB flushes for updates to mshare PTEs only being done on the local CPU. To ensure entries are flushed for non-local TLBs, set up an mmu notifier on the mshare mm and use the .arch_invalidate_secondary_tlbs callback to flush all TLBs. arch_invalidate_secondary_tlbs guarantees that TLB entries will be flushed before pages are freed when unmapping pages in an mshare region. Signed-off-by: Anthony Yznaga --- mm/mshare.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/mm/mshare.c b/mm/mshare.c index 6bdbcfa8deea..792d86c61042 100644 --- a/mm/mshare.c +++ b/mm/mshare.c @@ -16,8 +16,10 @@ #include #include #include +#include #include #include +#include =20 const unsigned long mshare_align =3D P4D_SIZE; const unsigned long mshare_base =3D mshare_align; @@ -29,6 +31,17 @@ struct mshare_data { unsigned long start; unsigned long size; unsigned long flags; + struct mmu_notifier mn; +}; + +static void mshare_invalidate_tlbs(struct mmu_notifier *mn, struct mm_stru= ct *mm, + unsigned long start, unsigned long end) +{ + flush_tlb_all(); +} + +static const struct mmu_notifier_ops mshare_mmu_ops =3D { + .arch_invalidate_secondary_tlbs =3D mshare_invalidate_tlbs, }; =20 static int mshare_vm_op_split(struct vm_area_struct *vma, unsigned long ad= dr) @@ -237,6 +250,10 @@ msharefs_fill_mm(struct inode *inode) m_data->mm =3D mm; m_data->start =3D mshare_base; inode->i_private =3D m_data; + m_data->mn.ops =3D &mshare_mmu_ops; + ret =3D mmu_notifier_register(&m_data->mn, mm); + if (ret) + goto err_free; =20 return 0; =20 --=20 2.43.5