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b=D s3tHqp43ssNDXomgsZBIvc4eGGgChOsGKqbB8qjdKMv2lHKagMLmabwzb4Spn3RE 8UddA5FG7r2qcfUPf4G5tP8KUJYLZHqeVXljFu6VvMXApZbymhc0YPnqs/PsM0QS 4Fnxf1X7QSNNc5XguswqkqWhMpjTO0axQxglgsgeTEf4Gx1J4t0rqWZJeQw6g2+H AF+2u3P0wFYeJK3k4oRR0a0AMEjmlhkfvKOwlYEI7nM/9Dv7/I0Wwo+taajRFHDB iePy1P7pfoaz1x/To3Yks5rBkethnWV4Fr0dFuVz+y77Ct+PM3h+DVhu5MXb7iTR gGGXfxoGKznCXx+o6b43g== 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 icm6tp2oYbWr; 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 4cX0g74qG5zyY6; Wed, 24 Sep 2025 17:11:31 +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 Subject: [PATCH v7 02/12] x86/tlb: export flush_tlb_kernel_range to KVM module Date: Wed, 24 Sep 2025 16:10:42 +0100 Message-ID: <20250924151101.2225820-3-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: itc9ne6f7ynipoiymcpoik6wnubjt4a8 X-Rspam-User: X-Rspamd-Queue-Id: 06D114000B X-Rspamd-Server: rspam10 X-HE-Tag: 1758726696-542243 X-HE-Meta: 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 IjIWh1jR 0Lb4ctG0ppQSss6tWAJHZkoRxs2oGens9bOBLoo1aZv5JmuER26GVHqE0l1O8LahihVmc1G/11EntWL3RQb/OIiW7EZEKCRSqEsyv9SS35QvJ8W8fsMMOWUUk9pFWgNoE0Bgxy/dEUcL+/pcPEdjqNGaTqojvirK5zX/2M4M0noQK02Z/1zaehkPGTObExBoo3rAsga5y5YzHI674tTplhhqDg25guS4P75KjspjGvPHJWvVRQbTOachkZq0DA1ITr9WK9//AVTr8D/EWQK/kIR+COJtEkX0FcNaY87ZuPOBoGSM= 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 After direct map removal, a TLB flush can be done to ensure that the just-unmapped memory cannot be accessed through stale TLB entries. This is particularly useful on modern hardware, where one can not rely on timely TLB-eviction to ensure these entries go away. This export is only needed on x86, as arm64 (the only other architecture supporting guest_memfd currently) does not allow building KVM as a module. Cc: Thomas Gleixner Signed-off-by: Patrick Roy --- arch/x86/include/asm/tlbflush.h | 3 ++- arch/x86/mm/tlb.c | 1 + 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index 00daedfefc1b..6f57f7eb621b 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -317,7 +317,6 @@ extern void flush_tlb_all(void); extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start, unsigned long end, unsigned int stride_shift, bool freed_tables); -extern void flush_tlb_kernel_range(unsigned long start, unsigned long end); static inline void flush_tlb_page(struct vm_area_struct *vma, unsigned long a) { @@ -483,6 +482,8 @@ static inline void cpu_tlbstate_update_lam(unsigned long lam, u64 untag_mask) #endif #endif /* !MODULE */ +extern void flush_tlb_kernel_range(unsigned long start, unsigned long end); + static inline void __native_tlb_flush_global(unsigned long cr4) { native_write_cr4(cr4 ^ X86_CR4_PGE); diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 39f80111e6f1..dee5018bceeb 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -1541,6 +1541,7 @@ void flush_tlb_kernel_range(unsigned long start, unsigned long end) put_flush_tlb_info(); } +EXPORT_SYMBOL_FOR_MODULES(flush_tlb_kernel_range, "kvm"); /* * This can be used from process context to figure out what the value of -- 2.51.0