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Tue, 16 Sep 2025 02:52:46 -0400 X-MC-Unique: n3TAo9g6MG-p5zGiFrRf-w-1 X-Mimecast-MFC-AGG-ID: n3TAo9g6MG-p5zGiFrRf-w_1758005564 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (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) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 51E8819560B0; Tue, 16 Sep 2025 06:52:43 +0000 (UTC) Received: from localhost (unknown [10.72.112.143]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id E92191800446; Tue, 16 Sep 2025 06:52:40 +0000 (UTC) Date: Tue, 16 Sep 2025 14:52:38 +0800 From: Pingfan Liu To: Philipp Rudo Cc: kexec@lists.infradead.org, Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , Jeremy Linton , Catalin Marinas , Will Deacon , Ard Biesheuvel , Simon Horman , Gerd Hoffmann , Vitaly Kuznetsov , Viktor Malik , Jan Hendrik Farr , Baoquan He , Dave Young , Andrew Morton , bpf@vger.kernel.org, systemd-devel@lists.freedesktop.org Subject: Re: [PATCHv5 06/12] kexec: Integrate with the introduced bpf kfuncs Message-ID: References: <20250819012428.6217-1-piliu@redhat.com> <20250819012428.6217-7-piliu@redhat.com> <20250901163042.721db92d@rotkaeppchen> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250901163042.721db92d@rotkaeppchen> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 On Mon, Sep 01, 2025 at 04:30:42PM +0200, Philipp Rudo wrote: > Hi Pingfan, > > > On Tue, 19 Aug 2025 09:24:22 +0800 > Pingfan Liu wrote: > > > This patch does two things: > > First, register as a listener on bpf_copy_to_kernel() > > Second, in order that the hooked bpf-prog can call the sleepable kfuncs, > > bpf_handle_pefile and bpf_post_handle_pefile are marked as > > KF_SLEEPABLE. > > > > Signed-off-by: Pingfan Liu > > Cc: Alexei Starovoitov > > Cc: Philipp Rudo > > Cc: Baoquan He > > Cc: Dave Young > > Cc: Andrew Morton > > Cc: bpf@vger.kernel.org > > To: kexec@lists.infradead.org > > --- > > kernel/kexec_pe_image.c | 67 +++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 67 insertions(+) > > > > diff --git a/kernel/kexec_pe_image.c b/kernel/kexec_pe_image.c > > index b0cf9942e68d2..f8debcde6b516 100644 > > --- a/kernel/kexec_pe_image.c > > +++ b/kernel/kexec_pe_image.c > > @@ -38,6 +38,51 @@ static struct kexec_res parsed_resource[3] = { > > { KEXEC_RES_CMDLINE_NAME, }, > > }; > > > > +/* > > + * @name should be one of : kernel, initrd, cmdline > > + */ > > +static int bpf_kexec_carrier(const char *name, struct mem_range_result *r) > > +{ > > + struct kexec_res *res; > > + int i; > > + > > + if (!r || !name) > > + return -EINVAL; > > + > > + for (i = 0; i < 3; i++) { > > + if (!strcmp(parsed_resource[i].name, name)) > > + break; > > + } > > + if (i >= 3) > > + return -EINVAL; > > Can you please replace the magic '3' by ARRAY_SIZE, just like you did > below when (un-)registering the listener. > Yes, I will introduce a macro KEXEC_RES_ARRAY_SIZE to unify all of them. Thanks, Pingfan > Thanks > Philipp > > > + > > + res = &parsed_resource[i]; > > + /* > > + * Replace the intermediate resource generated by the previous step. > > + */ > > + if (!!res->r) > > + mem_range_result_put(res->r); > > + mem_range_result_get(r); > > + res->r = r; > > + return 0; > > +} > > + > > +static struct carrier_listener kexec_res_listener[3] = { > > + { .name = KEXEC_RES_KERNEL_NAME, > > + .alloc_type = 1, > > + .handler = bpf_kexec_carrier, > > + }, > > + { .name = KEXEC_RES_INITRD_NAME, > > + .alloc_type = 1, > > + .handler = bpf_kexec_carrier, > > + }, > > + { .name = KEXEC_RES_CMDLINE_NAME, > > + /* kmalloc-ed */ > > + .alloc_type = 0, > > + .handler = bpf_kexec_carrier, > > + }, > > +}; > > + > > static bool pe_has_bpf_section(const char *file_buf, unsigned long pe_sz); > > > > static bool is_valid_pe(const char *kernel_buf, unsigned long kernel_len) > > @@ -159,6 +204,22 @@ __attribute__((used, optimize("O0"))) void bpf_post_handle_pefile(struct kexec_c > > dummy += 2; > > } > > > > +BTF_KFUNCS_START(kexec_modify_return_ids) > > +BTF_ID_FLAGS(func, bpf_handle_pefile, KF_SLEEPABLE) > > +BTF_ID_FLAGS(func, bpf_post_handle_pefile, KF_SLEEPABLE) > > +BTF_KFUNCS_END(kexec_modify_return_ids) > > + > > +static const struct btf_kfunc_id_set kexec_modify_return_set = { > > + .owner = THIS_MODULE, > > + .set = &kexec_modify_return_ids, > > +}; > > + > > +static int __init kexec_bpf_prog_run_init(void) > > +{ > > + return register_btf_fmodret_id_set(&kexec_modify_return_set); > > +} > > +late_initcall(kexec_bpf_prog_run_init); > > + > > /* > > * PE file may be nested and should be unfold one by one. > > * Query 'kernel', 'initrd', 'cmdline' in cur_phase, as they are inputs for the > > @@ -213,6 +274,9 @@ static void *pe_image_load(struct kimage *image, > > cmdline_start = cmdline; > > cmdline_sz = cmdline_len; > > > > + for (int i = 0; i < ARRAY_SIZE(kexec_res_listener); i++) > > + register_carrier_listener(&kexec_res_listener[i]); > > + > > while (is_valid_format(linux_start, linux_sz) && > > pe_has_bpf_section(linux_start, linux_sz)) { > > struct kexec_context context; > > @@ -250,6 +314,9 @@ static void *pe_image_load(struct kimage *image, > > disarm_bpf_prog(); > > } > > > > + for (int i = 0; i < ARRAY_SIZE(kexec_res_listener); i++) > > + unregister_carrier_listener(kexec_res_listener[i].name); > > + > > /* > > * image's kernel_buf, initrd_buf, cmdline_buf are set. Now they should > > * be updated to the new content. >