From patchwork Fri Apr 11 05:37:38 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Changyuan Lyu X-Patchwork-Id: 14047592 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BBEECC369A2 for ; Fri, 11 Apr 2025 05:51:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:Cc:To:From: Subject:Message-ID:References:Mime-Version:In-Reply-To:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=NQ4ycF7gsLT06FnekoMeMnv8oicyD3TdT/CesWgek8A=; b=WlcOAGS5+MRjZN14IofF5ZqmJc iZWmI62mj5d5cathkstcmQvPujyKe2zVuzl12RosbOhYcFPTNzqGbLCTpZ/EkdEZZUmi5z31a9w7a EKMU4Qz44KB7XSCRPuZWWhdURAF11I42SaVt0HDHKMV21dAGyqk59gmtu89UWSX/9ZyWZfPePBzPd J3BT1dTQbwJ6RlRuxlR9HgTowzoong7EnWjXFsisyZjkdfzi/VT3kXZzMVTJHIic0rltCHQ3D0OY2 SufL9Koh8aArFD6xGCLyyE/eC0mOoJFtP5pYlUALv/iU/4LjseYcCwKE7U7NUz5RQE87TONMgKi6F RwI5eOUQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u37IP-0000000CcDy-1RBj; Fri, 11 Apr 2025 05:51:21 +0000 Received: from mail-pg1-x54a.google.com ([2607:f8b0:4864:20::54a]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1u3760-0000000CYUr-2nU9 for linux-arm-kernel@lists.infradead.org; Fri, 11 Apr 2025 05:38:35 +0000 Received: by mail-pg1-x54a.google.com with SMTP id 41be03b00d2f7-af423fb4f0eso1095490a12.0 for ; Thu, 10 Apr 2025 22:38:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1744349911; x=1744954711; darn=lists.infradead.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=NQ4ycF7gsLT06FnekoMeMnv8oicyD3TdT/CesWgek8A=; b=VNAqYjndcx/J6VxyZlGgR4rBtWC0ohiK2NtQmsAci9n1mg2GDF7b8ydg4mIyz94Hla pDoPrA+vKCvcXh5CAk4O7VWie9rdwwwk+wEaomIgt2lMKHTn2HmhBYLup9ONPTYDSCIf vOTuz0ifehPxNMavge1qXwEI1P5AOvmeoTSEy/nyiWxw3M5+cfjKODtq44zYbIzK+UCT S69ywvVoxKoB4ollpkSXFr++HL3Flgu4zMEq5+82YSX+XhGAAzlL/ypfEMzGaVFt4vOS eUyhsd73yt1CUni2JT1NVL0myhLk5UDqNj47HrspcjU7BhKpel/OfhDOu2+C8G7cmKuv MJ5g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1744349911; x=1744954711; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=NQ4ycF7gsLT06FnekoMeMnv8oicyD3TdT/CesWgek8A=; b=qzjti4ug0o1f6pDuw85ZRlxVdko8hft/qD5SYmkYKXHJCmaCWSeTXLZvwUlVabsT+F 25hesrXu26LBKTZ9b0TPjwOMJhLuatA8o3dREEFeqY9zzdlNrrrX+yaQu8DmcHw9PHO+ VzN/BK3UrFWC9Pahi7IoRzamEB2DiZO09GXhZsTvkxu4Qc/27cVfbqS+++IOT6DYzREp wiyWABjENfwVzk0skRu4gKWKwIpIGjJ3DsYT9/Aayvl4lf1GWRnB6qz7j/KDKgDHyuvw 4CyJe8MPL2eiTLCvU5O1hCkKpU+S1vxhYn7tZ7cglTOimibR6uz5vfSjenjeFg7UE/W2 48fA== X-Forwarded-Encrypted: i=1; AJvYcCUYccpvRgN4cmUhSJJAPtc0aO+OKxPc+jscjdhMVPV7cEI5uTRlZbMIgnqpR2DHGZONEzo1k/IT7KEx/lGr0NCF@lists.infradead.org X-Gm-Message-State: AOJu0YzGRepW6Sg7nVAw0havIaXz5LqvLgdyPSIYfhNuXSGsDMB5z87m G7Wf+aNhQf9VNrxd39BqkoidKmZjbquLgUovan7s35mGZYRfQPvwa5hdLA5huQa9tQ13E8UuBn2 bv0V9mG8PLvdlaxhY7w== X-Google-Smtp-Source: AGHT+IFmHMamHSCxGJ9jONFAPmV1A91iPoS28bApZs3vQoT8HryanIff8vx754Cryl7fBwGV08e16HC+nkdncy1g X-Received: from plcc1.prod.google.com ([2002:a17:902:c1c1:b0:220:da6b:5d08]) (user=changyuanl job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:f705:b0:220:e9ac:e746 with SMTP id d9443c01a7336-22bea4fdc7amr25793305ad.53.1744349911576; Thu, 10 Apr 2025 22:38:31 -0700 (PDT) Date: Thu, 10 Apr 2025 22:37:38 -0700 In-Reply-To: <20250411053745.1817356-1-changyuanl@google.com> Mime-Version: 1.0 References: <20250411053745.1817356-1-changyuanl@google.com> X-Mailer: git-send-email 2.49.0.604.gff1f9ca942-goog Message-ID: <20250411053745.1817356-8-changyuanl@google.com> Subject: [PATCH v6 07/14] kexec: add KHO support to kexec file loads From: Changyuan Lyu To: linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org, anthony.yznaga@oracle.com, arnd@arndb.de, ashish.kalra@amd.com, benh@kernel.crashing.org, bp@alien8.de, catalin.marinas@arm.com, corbet@lwn.net, dave.hansen@linux.intel.com, devicetree@vger.kernel.org, dwmw2@infradead.org, ebiederm@xmission.com, graf@amazon.com, hpa@zytor.com, jgowans@amazon.com, kexec@lists.infradead.org, krzk@kernel.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, luto@kernel.org, mark.rutland@arm.com, mingo@redhat.com, pasha.tatashin@soleen.com, pbonzini@redhat.com, peterz@infradead.org, ptyadav@amazon.de, robh@kernel.org, rostedt@goodmis.org, rppt@kernel.org, saravanak@google.com, skinsburskii@linux.microsoft.com, tglx@linutronix.de, thomas.lendacky@amd.com, will@kernel.org, x86@kernel.org, Changyuan Lyu X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250410_223832_712364_C5E58916 X-CRM114-Status: GOOD ( 23.59 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Alexander Graf Kexec has 2 modes: A user space driven mode and a kernel driven mode. For the kernel driven mode, kernel code determines the physical addresses of all target buffers that the payload gets copied into. With KHO, we can only safely copy payloads into the "scratch area". Teach the kexec file loader about it, so it only allocates for that area. In addition, enlighten it with support to ask the KHO subsystem for its respective payloads to copy into target memory. Also teach the KHO subsystem how to fill the images for file loads. Signed-off-by: Alexander Graf Co-developed-by: Mike Rapoport (Microsoft) Signed-off-by: Mike Rapoport (Microsoft) Co-developed-by: Changyuan Lyu Signed-off-by: Changyuan Lyu --- include/linux/kexec.h | 7 +++++ kernel/kexec_file.c | 13 ++++++++ kernel/kexec_handover.c | 67 +++++++++++++++++++++++++++++++++++++++++ kernel/kexec_internal.h | 16 ++++++++++ 4 files changed, 103 insertions(+) diff --git a/include/linux/kexec.h b/include/linux/kexec.h index c8971861521a5..d3cad108b8076 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -371,6 +371,13 @@ struct kimage { size_t ima_buffer_size; #endif +#ifdef CONFIG_KEXEC_HANDOVER + struct { + struct kexec_segment *scratch; + phys_addr_t fdt; + } kho; +#endif + /* Core ELF header buffer */ void *elf_headers; unsigned long elf_headers_sz; diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index fba686487e3b5..77758c5331229 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -253,6 +253,11 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, /* IMA needs to pass the measurement list to the next kernel. */ ima_add_kexec_buffer(image); + /* If KHO is active, add its images to the list */ + ret = kho_fill_kimage(image); + if (ret) + goto out; + /* Call image load handler */ ldata = kexec_image_load_default(image); @@ -648,6 +653,14 @@ int kexec_locate_mem_hole(struct kexec_buf *kbuf) if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN) return 0; + /* + * If KHO is active, only use KHO scratch memory. All other memory + * could potentially be handed over. + */ + ret = kho_locate_mem_hole(kbuf, locate_mem_hole_callback); + if (ret <= 0) + return ret; + if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) ret = kexec_walk_resources(kbuf, locate_mem_hole_callback); else diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c index a594da2a22912..4bbc6f5ef7230 100644 --- a/kernel/kexec_handover.c +++ b/kernel/kexec_handover.c @@ -23,6 +23,7 @@ * internal APIs. */ #include "../mm/internal.h" +#include "kexec_internal.h" #define KHO_FDT_COMPATIBLE "kho-v1" #define PROP_PRESERVED_MEMORY_MAP "preserved-memory-map" @@ -1184,3 +1185,69 @@ void __init kho_populate(phys_addr_t fdt_phys, u64 fdt_len, if (err) pr_warn("disabling KHO revival: %d\n", err); } + +/* Helper functions for kexec_file_load */ + +int kho_fill_kimage(struct kimage *image) +{ + ssize_t scratch_size; + int err = 0; + struct kexec_buf scratch; + + if (!kho_enable) + return 0; + + image->kho.fdt = page_to_phys(kho_out.ser.fdt); + + scratch_size = sizeof(*kho_scratch) * kho_scratch_cnt; + scratch = (struct kexec_buf){ + .image = image, + .buffer = kho_scratch, + .bufsz = scratch_size, + .mem = KEXEC_BUF_MEM_UNKNOWN, + .memsz = scratch_size, + .buf_align = SZ_64K, /* Makes it easier to map */ + .buf_max = ULONG_MAX, + .top_down = true, + }; + err = kexec_add_buffer(&scratch); + if (err) + return err; + image->kho.scratch = &image->segment[image->nr_segments - 1]; + + return 0; +} + +static int kho_walk_scratch(struct kexec_buf *kbuf, + int (*func)(struct resource *, void *)) +{ + int ret = 0; + int i; + + for (i = 0; i < kho_scratch_cnt; i++) { + struct resource res = { + .start = kho_scratch[i].addr, + .end = kho_scratch[i].addr + kho_scratch[i].size - 1, + }; + + /* Try to fit the kimage into our KHO scratch region */ + ret = func(&res, kbuf); + if (ret) + break; + } + + return ret; +} + +int kho_locate_mem_hole(struct kexec_buf *kbuf, + int (*func)(struct resource *, void *)) +{ + int ret; + + if (!kho_enable || kbuf->image->type == KEXEC_TYPE_CRASH) + return 1; + + ret = kho_walk_scratch(kbuf, func); + + return ret == 1 ? 0 : -EADDRNOTAVAIL; +} diff --git a/kernel/kexec_internal.h b/kernel/kexec_internal.h index d35d9792402d1..30a733a55a67b 100644 --- a/kernel/kexec_internal.h +++ b/kernel/kexec_internal.h @@ -39,4 +39,20 @@ extern size_t kexec_purgatory_size; #else /* CONFIG_KEXEC_FILE */ static inline void kimage_file_post_load_cleanup(struct kimage *image) { } #endif /* CONFIG_KEXEC_FILE */ + +struct kexec_buf; + +#ifdef CONFIG_KEXEC_HANDOVER +int kho_locate_mem_hole(struct kexec_buf *kbuf, + int (*func)(struct resource *, void *)); +int kho_fill_kimage(struct kimage *image); +#else +static inline int kho_locate_mem_hole(struct kexec_buf *kbuf, + int (*func)(struct resource *, void *)) +{ + return 1; +} + +static inline int kho_fill_kimage(struct kimage *image) { return 0; } +#endif /* CONFIG_KEXEC_HANDOVER */ #endif /* LINUX_KEXEC_INTERNAL_H */