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[2003:cb:c70f:6900:6c56:80f8:c14:6d2a]) by smtp.gmail.com with UTF8SMTPSA id ffacd0b85a97d-3a073c8ca72sm1597057f8f.4.2025.04.25.01.17.23 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 25 Apr 2025 01:17:25 -0700 (PDT) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, x86@kernel.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-trace-kernel@vger.kernel.org, David Hildenbrand , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , David Airlie , Simona Vetter , Andrew Morton , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , "Liam R. Howlett" , Lorenzo Stoakes , Vlastimil Babka , Jann Horn , Pedro Falcato , Peter Xu Subject: [PATCH v1 03/11] x86/mm/pat: introduce pfnmap_track() and pfnmap_untrack() Date: Fri, 25 Apr 2025 10:17:07 +0200 Message-ID: <20250425081715.1341199-4-david@redhat.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250425081715.1341199-1-david@redhat.com> References: <20250425081715.1341199-1-david@redhat.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 Content-Type: text/plain; charset="utf-8" Let's provide variants of track_pfn_remap() and untrack_pfn() that won't mess with VMAs, to replace the existing interface step-by-step. Add some documentation. Signed-off-by: David Hildenbrand Reviewed-by: Lorenzo Stoakes --- arch/x86/mm/pat/memtype.c | 14 ++++++++++++++ include/linux/pgtable.h | 33 +++++++++++++++++++++++++++++++++ 2 files changed, 47 insertions(+) diff --git a/arch/x86/mm/pat/memtype.c b/arch/x86/mm/pat/memtype.c index 193e33251b18f..c011d8dd8f441 100644 --- a/arch/x86/mm/pat/memtype.c +++ b/arch/x86/mm/pat/memtype.c @@ -1068,6 +1068,20 @@ int pfnmap_sanitize_pgprot(unsigned long pfn, unsign= ed long size, pgprot_t *prot return 0; } =20 +int pfnmap_track(unsigned long pfn, unsigned long size, pgprot_t *prot) +{ + const resource_size_t paddr =3D (resource_size_t)pfn << PAGE_SHIFT; + + return reserve_pfn_range(paddr, size, prot, 0); +} + +void pfnmap_untrack(unsigned long pfn, unsigned long size) +{ + const resource_size_t paddr =3D (resource_size_t)pfn << PAGE_SHIFT; + + free_pfn_range(paddr, size); +} + /* * untrack_pfn is called while unmapping a pfnmap for a region. * untrack can be called for a specific region indicated by pfn and size or diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 91aadfe2515a5..898a3ab195578 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -1506,6 +1506,16 @@ static inline int pfnmap_sanitize_pgprot(unsigned lo= ng pfn, unsigned long size, return 0; } =20 +static inline int pfnmap_track(unsigned long pfn, unsigned long size, + pgprot_t *prot) +{ + return 0; +} + +static inline void pfnmap_untrack(unsigned long pfn, unsigned long size) +{ +} + /* * track_pfn_copy is called when a VM_PFNMAP VMA is about to get the page * tables copied during copy_page_range(). Will store the pfn to be @@ -1570,6 +1580,29 @@ extern int track_pfn_remap(struct vm_area_struct *vm= a, pgprot_t *prot, */ int pfnmap_sanitize_pgprot(unsigned long pfn, unsigned long size, pgprot_t *prot); + +/** + * pfnmap_track - track a pfn range + * @pfn: the start of the pfn range + * @size: the size of the pfn range + * @prot: the pgprot to track + * + * Tracking a pfnmap range involves conditionally reserving a pfn range and + * sanitizing the pgprot -- see pfnmap_sanitize_pgprot(). + * + * Returns 0 on success and -EINVAL on error. + */ +int pfnmap_track(unsigned long pfn, unsigned long size, pgprot_t *prot); + +/** + * pfnmap_untrack - untrack a pfn range + * @pfn: the start of the pfn range + * @size: the size of the pfn range + * + * Untrack a pfn range previously tracked through pfnmap_track(), for exam= ple, + * un-doing any reservation. + */ +void pfnmap_untrack(unsigned long pfn, unsigned long size); extern int track_pfn_copy(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, unsigned long *pfn); extern void untrack_pfn_copy(struct vm_area_struct *dst_vma, --=20 2.49.0