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Tue, 06 Jan 2026 07:50:00 -0800 (PST) MIME-Version: 1.0 References: <20251211125928.3258905-1-smostafa@google.com> <20251211125928.3258905-2-smostafa@google.com> <341bbfd9-e6bb-4d1e-b9c0-9077dc3eaba3@linux.intel.com> In-Reply-To: <341bbfd9-e6bb-4d1e-b9c0-9077dc3eaba3@linux.intel.com> From: Mostafa Saleh Date: Tue, 6 Jan 2026 15:49:48 +0000 X-Gm-Features: AQt7F2oA1CBb4GrIbCitr-B-G-VTljeq1aZHCjWlK0-2EsS6hRvCfN68ucTwj3A Message-ID: Subject: Re: [PATCH v4 1/4] iommu: Add page_ext for IOMMU_DEBUG_PAGEALLOC To: Baolu Lu Cc: linux-mm@kvack.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, corbet@lwn.net, joro@8bytes.org, will@kernel.org, robin.murphy@arm.com, akpm@linux-foundation.org, vbabka@suse.cz, surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com, david@redhat.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, rppt@kernel.org, xiaqinxin@huawei.com, rdunlap@infradead.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: a4xesygc79gu6s69sgimba4hrimpxfpt X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 3F87940010 X-HE-Tag: 1767714601-440621 X-HE-Meta: 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 eyPpLVNp TkfIMTpc3hSQxvxg1mVPxJgiqRaEPJha8+5romuh9MKd4yOvvftnYn7l1PgvR2AjeXrmEyziuZWY2yssbtEOAM46HWgqYqioQScHIQ89d6tIV3ymJm1bIMMgvN3uq5iLJ5ZywFnoNlzdUs2TYQWdbiMB4RXjDMBQEXTdD8q2Mh9+Ry+dl8XUYud0WaA+adDXfzrcdSfRmPz4t82vj+zJKbgkHJebvE4uO1KSy3KqnsO3RdxZKAqXYDoJUdA+Px1IqZMunXcOkGXtGdphSrdaC3x0mDa9pPL3vCXE1Jfphyv6Ysq8zC8o7xgHpJ2Iy4XQFHRF+dtzb9hb0XaU= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Dec 12, 2025 at 2:22=E2=80=AFAM Baolu Lu = wrote: > > On 12/11/25 20:59, Mostafa Saleh wrote: > > Add a new config IOMMU_DEBUG_PAGEALLOC, which registers new data to > > page_ext. > > > > This config will be used by the IOMMU API to track pages mapped in > > the IOMMU to catch drivers trying to free kernel memory that they > > still map in their domains, causing all types of memory corruption. > > > > This behaviour is disabled by default and can be enabled using > > kernel cmdline iommu.debug_pagealloc. > > > > Signed-off-by: Mostafa Saleh > > --- > > .../admin-guide/kernel-parameters.txt | 9 ++++++ > > drivers/iommu/Kconfig | 19 +++++++++++ > > drivers/iommu/Makefile | 1 + > > drivers/iommu/iommu-debug-pagealloc.c | 32 ++++++++++++++++++= + > > include/linux/iommu-debug-pagealloc.h | 17 ++++++++++ > > mm/page_ext.c | 4 +++ > > 6 files changed, 82 insertions(+) > > create mode 100644 drivers/iommu/iommu-debug-pagealloc.c > > create mode 100644 include/linux/iommu-debug-pagealloc.h > > Do you need to update the MAINTAINERS file, since a new file (iommu- > debug-pagealloc.h) is being added? > Sorry I missed this last time, that should be under the path of "IOMMU SUBSYSTEM", I am happy to maintain it, but it's up to Joerg and Will. Thanks, Mostafa > > > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Document= ation/admin-guide/kernel-parameters.txt > > index a8d0afde7f85..d484d9d8d0a4 100644 > > --- a/Documentation/admin-guide/kernel-parameters.txt > > +++ b/Documentation/admin-guide/kernel-parameters.txt > > @@ -2675,6 +2675,15 @@ Kernel parameters > > 1 - Bypass the IOMMU for DMA. > > unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHR= OUGH. > > > > + iommu.debug_pagealloc=3D > > + [KNL,EARLY] When CONFIG_IOMMU_DEBUG_PAGEALLOC is = set, this > > + parameter enables the feature at boot time. By de= fault, it > > + is disabled and the system behaves the same way a= s a kernel > > + built without CONFIG_IOMMU_DEBUG_PAGEALLOC. > > + Format: { "0" | "1" } > > + 0 - Sanitizer disabled. > > + 1 - Sanitizer enabled, expect runtime overhead. > > "iommu.debug_pagealloc=3D0" has the same meaning as "unset". Would > "iommu=3Ddebug_pagealloc" look more appropriate? > > > + > > io7=3D [HW] IO7 for Marvel-based Alpha systems > > See comment before marvel_specify_io7 in > > arch/alpha/kernel/core_marvel.c. > > [ ... ] > > Other changes look good to me. > > Reviewed-by: Lu Baolu