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b=X4R3k1LZHzpGoa3CGNOP1VANnxZgqbYFTh3O1uI0UOUZI6egZH7DS9iXzCNanfPj6 5l4hRVdl8kug78iGi503BMwTf4nOfB4vvPqzfQblO8bANCTR0IepYFAi8pg4PmXcJl v5mRsMXje08tODxTmyA5OIz0MV0Bp+hR52IAzNGX/P+svL+EdB5DLwEoWOUND+O6Kf YuSG4fNpL6qP9OxqgNyTvU+dffpgHu93yEHMZLAsR25uNDeEeJ6nise1nSkPELIGCx VGgNLmvwA2eaX+H2UuCy8fUgkQfgvKdAEN9XvtoacZlIyOarhWxcIvseAbwa+xrPpj rWlSnFWp2aHtA== Date: Mon, 13 Oct 2025 10:17:55 +0300 From: Mike Rapoport To: Lu Baolu Cc: Joerg Roedel , Will Deacon , Robin Murphy , Kevin Tian , Jason Gunthorpe , Jann Horn , Vasant Hegde , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Alistair Popple , Peter Zijlstra , Uladzislau Rezki , Jean-Philippe Brucker , Andy Lutomirski , Yi Lai , iommu@lists.linux.dev, security@kernel.org, x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Dave Hansen Subject: Re: [PATCH v5 2/8] mm: Actually mark kernel page table pages Message-ID: References: <20250919054007.472493-1-baolu.lu@linux.intel.com> <20250919054007.472493-3-baolu.lu@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250919054007.472493-3-baolu.lu@linux.intel.com> X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 69DD11C0006 X-Stat-Signature: ogqqxmyrhbdx68zgxj715tf8rxwy1kw8 X-Rspam-User: X-HE-Tag: 1760339889-651354 X-HE-Meta: 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 CR+zkoKW PKBlCb+oZJn7Ho3ZBAPecAVvYSIc3NERjyYgDtFeP/oFPmDGSiKgLGaASx4vKROVS4ruxPGl4CEBnbjQ1+cdmnCVyQIjC+YRwpPKriU52R63ZlZt1Jqpy3mxNdNDC0/ulMypGXHlG/wEPY/quqAYlQAHhQu7+zfT2JdWQzm5fSkvwr8wiWHJUDByuzFYP9EbW5QRoWWPiER4Z9Krx6aevWfEtYhYoLFc3Ec2yinSfrmcpQ8HiGV/hDzDZAUhiPfx+66xCfOFfMZCw12rNY/7Z5yJJI1pGmEdlRIEBkADfo+mO8DJ4llf5FGS33fDjsleTIKIzbPVDvGOFCMsYcckfDSIm11heUOqtAM8sA1oDdD/FVX4= 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, Sep 19, 2025 at 01:40:00PM +0800, Lu Baolu wrote: > From: Dave Hansen > > Now that the API is in place, mark kernel page table pages just > after they are allocated. Unmark them just before they are freed. > > Note: Unconditionally clearing the 'kernel' marking (via > ptdesc_clear_kernel()) would be functionally identical to what > is here. But having the if() makes it logically clear that this > function can be used for kernel and non-kernel page tables. > > Signed-off-by: Dave Hansen > Signed-off-by: Lu Baolu > Reviewed-by: Jason Gunthorpe > Reviewed-by: Kevin Tian Acked-by: Mike Rapoport (Microsoft) > --- > include/asm-generic/pgalloc.h | 18 ++++++++++++++++++ > include/linux/mm.h | 3 +++ > 2 files changed, 21 insertions(+) > > diff --git a/include/asm-generic/pgalloc.h b/include/asm-generic/pgalloc.h > index 3c8ec3bfea44..b9d2a7c79b93 100644 > --- a/include/asm-generic/pgalloc.h > +++ b/include/asm-generic/pgalloc.h > @@ -28,6 +28,8 @@ static inline pte_t *__pte_alloc_one_kernel_noprof(struct mm_struct *mm) > return NULL; > } > > + ptdesc_set_kernel(ptdesc); > + > return ptdesc_address(ptdesc); > } > #define __pte_alloc_one_kernel(...) alloc_hooks(__pte_alloc_one_kernel_noprof(__VA_ARGS__)) > @@ -146,6 +148,10 @@ static inline pmd_t *pmd_alloc_one_noprof(struct mm_struct *mm, unsigned long ad > pagetable_free(ptdesc); > return NULL; > } > + > + if (mm == &init_mm) > + ptdesc_set_kernel(ptdesc); > + > return ptdesc_address(ptdesc); > } > #define pmd_alloc_one(...) alloc_hooks(pmd_alloc_one_noprof(__VA_ARGS__)) > @@ -179,6 +185,10 @@ static inline pud_t *__pud_alloc_one_noprof(struct mm_struct *mm, unsigned long > return NULL; > > pagetable_pud_ctor(ptdesc); > + > + if (mm == &init_mm) > + ptdesc_set_kernel(ptdesc); > + > return ptdesc_address(ptdesc); > } > #define __pud_alloc_one(...) alloc_hooks(__pud_alloc_one_noprof(__VA_ARGS__)) > @@ -233,6 +243,10 @@ static inline p4d_t *__p4d_alloc_one_noprof(struct mm_struct *mm, unsigned long > return NULL; > > pagetable_p4d_ctor(ptdesc); > + > + if (mm == &init_mm) > + ptdesc_set_kernel(ptdesc); > + > return ptdesc_address(ptdesc); > } > #define __p4d_alloc_one(...) alloc_hooks(__p4d_alloc_one_noprof(__VA_ARGS__)) > @@ -277,6 +291,10 @@ static inline pgd_t *__pgd_alloc_noprof(struct mm_struct *mm, unsigned int order > return NULL; > > pagetable_pgd_ctor(ptdesc); > + > + if (mm == &init_mm) > + ptdesc_set_kernel(ptdesc); > + > return ptdesc_address(ptdesc); > } > #define __pgd_alloc(...) alloc_hooks(__pgd_alloc_noprof(__VA_ARGS__)) > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 1ae97a0b8ec7..f3db3a5ebefe 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -2895,6 +2895,9 @@ static inline void pagetable_free(struct ptdesc *pt) > { > struct page *page = ptdesc_page(pt); > > + if (ptdesc_test_kernel(pt)) > + ptdesc_clear_kernel(pt); > + > __free_pages(page, compound_order(page)); > } > > -- > 2.43.0 > -- Sincerely yours, Mike.