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b=E RCmo7GN3cJorQyZx7veOPX1uJX526B979gcoqD9YQPNg2IlhNVxWPFsMFg+QS/q3 L/wVNxo8mJlMHtkp/bEvKP7Hn+Gec2q7CNLyZt0EpSMka0FGzp5jCLM+/4Q4Yf9m bVnNe2Tm7A8+i74QMY7Y1jxU7K7i3ZBWXNk3nMdvTZsDVJlux0h/VG4Yw7pbmUSO RpLfSu4b6GZEIpe3sZKqyNWAaDHGBchXBCWQzjhHNdflPiUJAQ9O1DmlqkXQb9EW Uhe+iIn9Bv6pA0Z2aDaAYUqxTzRjd0IKO7k1GlUoiaatpmzPZUMKJctUANGLq63W fc7ujWT6qB0l70vnk9IVA== X-Virus-Scanned: by amavisd-new at lrz.de in lxmhs52.srv.lrz.de Received: from postout2.mail.lrz.de ([127.0.0.1]) by lxmhs52.srv.lrz.de (lxmhs52.srv.lrz.de [127.0.0.1]) (amavis, port 20024) with LMTP id bdh52MywZE5f; Wed, 24 Sep 2025 17:11:34 +0200 (CEST) Received: from spacestation.cable.virginm.net (oxfd-27-b2-v4wan-164230-cust474.vm42.cable.virginm.net [86.22.133.219]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (Client did not present a certificate) by postout2.mail.lrz.de (Postfix) with ESMTPSA id 4cX0g40m58zyXY; Wed, 24 Sep 2025 17:11:28 +0200 (CEST) From: Patrick Roy To: Cc: Patrick Roy , pbonzini@redhat.com, corbet@lwn.net, maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, luto@kernel.org, peterz@infradead.org, willy@infradead.org, akpm@linux-foundation.org, david@redhat.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, song@kernel.org, jolsa@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jgg@ziepe.ca, jhubbard@nvidia.com, peterx@redhat.com, jannh@google.com, pfalcato@suse.de, shuah@kernel.org, seanjc@google.com, kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, xmarcalx@amazon.co.uk, kalyazin@amazon.co.uk, jackabt@amazon.co.uk, derekmn@amazon.co.uk, tabba@google.com, ackerleytng@google.com, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org Subject: [PATCH v7 01/12] arch: export set_direct_map_valid_noflush to KVM module Date: Wed, 24 Sep 2025 16:10:41 +0100 Message-ID: <20250924151101.2225820-2-patrick.roy@campus.lmu.de> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250924151101.2225820-1-patrick.roy@campus.lmu.de> References: <20250924151101.2225820-1-patrick.roy@campus.lmu.de> MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Stat-Signature: 71doqgtwqgs51ds7zsrk7qq94wkg3yuz X-Rspam-User: X-Rspamd-Queue-Id: 930DF40011 X-Rspamd-Server: rspam04 X-HE-Tag: 1758726696-888744 X-HE-Meta: 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 sh8trKW/ cd+GqXfHtQqkHhKcYscV6oBqqnLGmfceDikKZL+5nrw6KTLBi4KfNTkbFgHJlCp+swTeogVDB3rmvKoXv9orrL8azKWtvEFi/pgBqlcJetXMl0EBBSsQA13CxlJ83Aa2OzcxHg6KgRiu8U+q1YPBl8em6REmTevO5FJh6g6AgMHdQ5EtGO7OuLjAumHc2sehs7Rw9drBa1rSH14hiDxPsp6PG594TfgCyF60RgF2y8jjOT944Iqs5IH8aGwIy2Iao0JZOh2hNQka2kSgAt5e4sDDkHqx69HnTnist6Zj7o9tvNPbgooBf1HWSQQUHWZvcGh/N5QWOFBsmTqYN65x16/Vk3yYZB8C500CgSXE3iXdS/om4Ut4iJylRVI97QINIkM1PvdvkbT7wuCX8VJ9uzeqHXA== 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: From: Patrick Roy Use the new per-module export functionality to allow KVM (and only KVM) access to set_direct_map_valid_noflush(). This allows guest_memfd to remove its memory from the direct map, even if KVM is built as a module. Direct map removal gives guest_memfd the same protection that memfd_secret enjoys, such as hardening against Spectre-like attacks through in-kernel gadgets. Cc: linux-arm-kernel@lists.infradead.org Cc: loongarch@lists.linux.dev Cc: linux-riscv@lists.infradead.org Cc: linux-s390@vger.kernel.org Reviewed-by: Fuad Tabba Signed-off-by: Patrick Roy --- arch/arm64/mm/pageattr.c | 1 + arch/loongarch/mm/pageattr.c | 1 + arch/riscv/mm/pageattr.c | 1 + arch/s390/mm/pageattr.c | 1 + arch/x86/mm/pat/set_memory.c | 1 + 5 files changed, 5 insertions(+) diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index 04d4a8f676db..4f3cddfab9b0 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -291,6 +291,7 @@ int set_direct_map_valid_noflush(struct page *page, unsigned nr, bool valid) return set_memory_valid(addr, nr, valid); } +EXPORT_SYMBOL_FOR_MODULES(set_direct_map_valid_noflush, "kvm"); #ifdef CONFIG_DEBUG_PAGEALLOC /* diff --git a/arch/loongarch/mm/pageattr.c b/arch/loongarch/mm/pageattr.c index f5e910b68229..458f5ae6a89b 100644 --- a/arch/loongarch/mm/pageattr.c +++ b/arch/loongarch/mm/pageattr.c @@ -236,3 +236,4 @@ int set_direct_map_valid_noflush(struct page *page, unsigned nr, bool valid) return __set_memory(addr, 1, set, clear); } +EXPORT_SYMBOL_FOR_MODULES(set_direct_map_valid_noflush, "kvm"); diff --git a/arch/riscv/mm/pageattr.c b/arch/riscv/mm/pageattr.c index 3f76db3d2769..6db31040cd66 100644 --- a/arch/riscv/mm/pageattr.c +++ b/arch/riscv/mm/pageattr.c @@ -400,6 +400,7 @@ int set_direct_map_valid_noflush(struct page *page, unsigned nr, bool valid) return __set_memory((unsigned long)page_address(page), nr, set, clear); } +EXPORT_SYMBOL_FOR_MODULES(set_direct_map_valid_noflush, "kvm"); #ifdef CONFIG_DEBUG_PAGEALLOC static int debug_pagealloc_set_page(pte_t *pte, unsigned long addr, void *data) diff --git a/arch/s390/mm/pageattr.c b/arch/s390/mm/pageattr.c index 348e759840e7..8ffd9ef09bc6 100644 --- a/arch/s390/mm/pageattr.c +++ b/arch/s390/mm/pageattr.c @@ -413,6 +413,7 @@ int set_direct_map_valid_noflush(struct page *page, unsigned nr, bool valid) return __set_memory((unsigned long)page_to_virt(page), nr, flags); } +EXPORT_SYMBOL_FOR_MODULES(set_direct_map_valid_noflush, "kvm"); bool kernel_page_present(struct page *page) { diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c index 8834c76f91c9..87e9c7d2dcdc 100644 --- a/arch/x86/mm/pat/set_memory.c +++ b/arch/x86/mm/pat/set_memory.c @@ -2661,6 +2661,7 @@ int set_direct_map_valid_noflush(struct page *page, unsigned nr, bool valid) return __set_pages_np(page, nr); } +EXPORT_SYMBOL_FOR_MODULES(set_direct_map_valid_noflush, "kvm"); #ifdef CONFIG_DEBUG_PAGEALLOC void __kernel_map_pages(struct page *page, int numpages, int enable) -- 2.51.0