From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0AF51CCA47B for ; Wed, 8 Jun 2022 07:47:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230370AbiFHHrC (ORCPT ); Wed, 8 Jun 2022 03:47:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33424 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237563AbiFHHhs (ORCPT ); Wed, 8 Jun 2022 03:37:48 -0400 Received: from mail-pl1-x635.google.com (mail-pl1-x635.google.com [IPv6:2607:f8b0:4864:20::635]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 439F938BE1 for ; Wed, 8 Jun 2022 00:00:45 -0700 (PDT) Received: by mail-pl1-x635.google.com with SMTP id u18so16870814plb.3 for ; Wed, 08 Jun 2022 00:00:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references:reply-to :mime-version:content-transfer-encoding; bh=0Y71+75qvfs0BWzL6gBfrDn2lzjlHUL6hjQyt+wNtxI=; b=lFEEkahv8QX0NmHlMpbpwU3DLBoViwvS4Bkf2xwRJvGyqHFcvwgcjk+29VrBH/HQ0Y u0vev6U6R6NGWWY+5hhqbnvFYCLMBjlbwCUdjeEmeV0BjtdobRy6VRHrADqEiQkC5/CN 4TbqzIu9w0iAUgpRStiIJANJO5mYmsnsmuRmNSyCSrkPUkR38bgV3oGaenT8prRz4wQV wFRYSLtZ/+LseV5K4es+xa5RfcL3ueOtoSi9HJGtCtDhF5dlrKNfvlTiegxbbiCk4vCb qGsNB986MXJUCxJnXwRLo9xxzl/LSoh7xEfFLlQKUD35OPJYxdViOcXpsgMnRnEXaXtm HgEA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:reply-to:mime-version:content-transfer-encoding; bh=0Y71+75qvfs0BWzL6gBfrDn2lzjlHUL6hjQyt+wNtxI=; b=HyafTWjL8U4LN7CdaU5KDPd9wLsd6V3mmP+5G04R37a+iu9lRd4ieEdn68jbUaWshp OYzsBdkTpz46/cdzuNLcTQ5C6iEN9gzR4dbXOHtglpyJoc9zUjDJOQOHRd3GYXOStqse gECP1bUSws2yqMCGcErmVYpZmN0rbGT0HrVOQBAGRqAg6hcCJ2te5zXPBgqhAW/YiEaw KOMNAKyMZ3ccv0HEHRHe9ldc33KHmaUmpAsGQvMGzbmx6yg9ZkgFRIh+GoyWNfqMMPu0 G6jsKV/Bm5LI4msxfdJ+nLBpsCmagSetrlHvoP4bgvfx/fYz4MZYaoJ7qdQThFaSxvZZ nR9w== X-Gm-Message-State: AOAM532eBYVTsOOxNnWFtZGhww+5VvgyafKPJ8BdBWV4n55C375EXXLU bdvfkDcwFJnC9vl1d07DIQgK3pjNXCiqAh8x X-Google-Smtp-Source: ABdhPJx7+Tm4FFC4r7PiYQy5839YKi2Ajm/KYt944nHUrPqCBYGoBDa99piJ/g1V0Xo5JM25LyktVw== X-Received: by 2002:a17:902:f687:b0:167:58bb:c43f with SMTP id l7-20020a170902f68700b0016758bbc43fmr22706267plg.136.1654671644069; Wed, 08 Jun 2022 00:00:44 -0700 (PDT) Received: from KASONG-MB0.tencent.com ([103.7.29.31]) by smtp.gmail.com with ESMTPSA id e18-20020a170902ed9200b001675991fb7fsm8396425plj.55.2022.06.08.00.00.41 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Wed, 08 Jun 2022 00:00:43 -0700 (PDT) From: Kairui Song To: linux-kernel@vger.kernel.org Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Eric Biederman , x86@kernel.org, kexec@lists.infradead.org, Kairui Song Subject: [PATCH 2/2] x86/mpparse, kexec: probe apic driver early for x2apic Date: Wed, 8 Jun 2022 14:43:48 +0800 Message-Id: <20220608064348.66402-3-ryncsn@gmail.com> X-Mailer: git-send-email 2.35.2 In-Reply-To: <20220608064348.66402-1-ryncsn@gmail.com> References: <20220608064348.66402-1-ryncsn@gmail.com> Reply-To: Kairui Song MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kairui Song Following kernel panic is observed when doing kdump/kexec on virtual machines that uses MPTABLE, not ACPI MADT, and supports x2apic: Intel MultiProcessor Specification v1.4 MPTABLE: OEM ID: BOCHSCPU MPTABLE: Product ID: 0.1 MPTABLE: APIC at: 0xFEE00000 BUG: unable to handle page fault for address: ffffffffff5fc020 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 25e15067 P4D 25e15067 PUD 25e17067 PMD 25e18067 PTE 0 Oops: 0000 [#1] SMP NOPTI CPU: 0 PID: 0 Comm: swapper Not tainted 5.14.10-300.fc35.x86_64 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1.fc35 04/01/2014 RIP: 0010:native_apic_mem_read+0x2/0x10 Code: 14 25 20 cd e3 82 c3 90 bf 30 08 00 00 ff 14 25 18 cd e3 82 c3 cc cc cc 89 ff 89 b7 00 c0 5f ff c3 0f 1f 80 00 00 00 00 89 ff <8b> 87 00 c0 5f ff c3 0f 1f 80 00 00 00 0 RSP: 0000:ffffffff82e03e18 EFLAGS: 00010046 RAX: ffffffff81064840 RBX: ffffffffff240b6c RCX: ffffffff82f17428 RDX: c0000000ffffdfff RSI: 00000000ffffdfff RDI: 0000000000000020 RBP: ffff888023200000 R08: 0000000000000000 R09: ffffffff82e03c50 R10: ffffffff82e03c48 R11: ffffffff82f47468 R12: ffffffffff240b40 R13: ffffffffff200b30 R14: 0000000000000000 R15: 00000000000000d4 FS: 0000000000000000(0000) GS:ffffffff8365b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff5fc020 CR3: 0000000025e10000 CR4: 00000000000006b0 Call Trace: ? read_apic_id+0x15/0x30 ? register_lapic_address+0x76/0x97 ? default_get_smp_config+0x28b/0x42d ? dmi_check_system+0x1c/0x60 ? acpi_boot_init+0x1d/0x4c3 ? setup_arch+0xb37/0xc2a ? slab_is_available+0x5/0x10 ? start_kernel+0x61/0x980 ? load_ucode_bsp+0x4c/0xcd ? secondary_startup_64_no_verify+0xc2/0xcb Modules linked in: CR2: ffffffffff5fc020 random: get_random_bytes called from oops_exit+0x35/0x60 with crng_init=0 ---[ end trace c9e569df3bdbefd3 ]--- The panic happens within following init code: setup_arch() .... check_x2apic() <-- x2apic is enabled by first kernel before kexec, this set x2apic_mode = 1, make sure later probes will recognize pre-enabled x2apic. .... acpi_boot_init(); <-- If ACPI MADT is in use, this will switch apic driver to x2apic, but it will do nothing with MPTABLE. x86_dtb_init(); get_smp_config(); default_get_smp_config(); <-- MPTABLE setup. check_physptr(); smp_read_mpc(); register_lapic_address(); <-- * panic here * init_apic_mappings(); .... The problem here is MPTABLE setup calls register_lapic_address(), which is still using apic_flat driver, and access the apic MMIO interface. But the address is never mapped for pre-enabled x2apic, since commit 0450193bffed6 ("x86, x2apic: Don't map lapic addr for preenabled x2apic systems"), then it panics. Simply map it won't work either, in x2apic mode the MMIO interface is not usable (Intel SDM Volume 3A 10.12.2), later setups will still fail with other errors. So it needs do a proper apic driver probe and switch to x2apic driver to perform MSR operation instead. Such issue is currently only seen with kdump/kexec, kernel enabled the x2apic in first kernel and kept it enabled to 2nd kernel. This can be easily reproduced with qemu-kvm, use -no-acpi and enable x2apic, so x2apic with MPTABLE will be in use, then trigger kdump/kexec. Signed-off-by: Kairui Song --- arch/x86/kernel/mpparse.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/mpparse.c b/arch/x86/kernel/mpparse.c index fed721f90116..7658c8184e8c 100644 --- a/arch/x86/kernel/mpparse.c +++ b/arch/x86/kernel/mpparse.c @@ -202,8 +202,10 @@ static int __init smp_read_mpc(struct mpc_table *mpc, unsigned early) return 0; /* Initialize the lapic mapping */ - if (!acpi_lapic) + if (!acpi_lapic) { + apic_early_probe(); register_lapic_address(mpc->lapic); + } if (early) return 1; -- 2.35.2