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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 D03A8C28D13 for ; Thu, 25 Aug 2022 13:38:04 +0000 (UTC) Received: from localhost ([::1]:56828 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oRD3Z-0004JK-E8 for qemu-devel@archiver.kernel.org; Thu, 25 Aug 2022 09:38:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45662) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oRD0m-0002Fj-W1 for qemu-devel@nongnu.org; Thu, 25 Aug 2022 09:35:09 -0400 Received: from mail-yw1-x112b.google.com ([2607:f8b0:4864:20::112b]:43740) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1oRD0i-0003V2-V4 for qemu-devel@nongnu.org; Thu, 25 Aug 2022 09:35:08 -0400 Received: by mail-yw1-x112b.google.com with SMTP id 00721157ae682-333a4a5d495so540819497b3.10 for ; Thu, 25 Aug 2022 06:34:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc; bh=57O8tsLQIj34+F9o/XXXiBF2UB6oMe/d1gKDRn8OWlQ=; b=WZMhTuiSZsbGVVVAECE7hnZtP0tIl4O3yqTMBjRIX/GC/SpzPdt4/u68H3uWmSRMpx XGea+4A5X1yAixrLR+O8G5Br1ZO3uiQsYhi6eAYT+nge/tAOGrS3HRxsf5D5A7XKzBRl uEbII1AyOlUIa82G3IoT/dbgBBxB/671nK/5sfn9dXUpAcCNCrKHLTKeO3vXk5oPpIZM EpQCu+PWNjFncXKDj++q/VszSZZEs8l+3QEgsB6qlaEoYOXxLl3SMVtMWCIonBzi5Tx6 SbBjGDlw234foyFG0iSYE1hC/KagrpDQXQtgoBj9+TuDPzjOOJ4lZCSza81BnEp0zzX9 lPJQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc; bh=57O8tsLQIj34+F9o/XXXiBF2UB6oMe/d1gKDRn8OWlQ=; b=Kzl4Kj0kAwavRRcWzOUIaz7LcYVyeJVAJWrcCUZlfNZ5bYwCMdyIcxVd0kChGKiiFt 3ST28h2u2+irqfWW58PzMci+1nU4E4N+zeHql/oUstYvEmWAcsuyFUPIOhO0MYjtKBPU qLueX4DZv3Y8suc0o2PmYT2R4ht1xXUP4TRcOV37fLyBAHQeudPZALl7jmN0RYalL2Qe yE80wzgNriw5K7qgb0VHm/oW4LAvixLdrl4T/HOIUAfRvfglyha3LNFmQvNeYszpg+5X DFo1V4pWBQ/Aj6zDvGQsfFm+tJSMjhUTM8y80T6bATKioX1OVw7fAsFFuBGB81bb1G2n DdZw== X-Gm-Message-State: ACgBeo2O1kJBhlqxVPU/0rWRrbHdhrV9AVayLWwLvuzESxDUxm+GKzYB FOAQFbpQj52Qy0sAx0fKaM+FK0/2xephz6cO7kdh+w== X-Google-Smtp-Source: AA6agR4vY7jwTCRj5pyXYBm/5CEsZQbTdS2hVf75m4RnDTSeLf0g9E0iDeY4Iog6pVY3YTeNVrGnNkgZbZ0jLPMmcCQ= X-Received: by 2002:a5b:7c6:0:b0:670:6ba6:d046 with SMTP id t6-20020a5b07c6000000b006706ba6d046mr3276353ybq.140.1661434498551; Thu, 25 Aug 2022 06:34:58 -0700 (PDT) MIME-Version: 1.0 References: <20220825132110.1500330-1-marcandre.lureau@redhat.com> <20220825132110.1500330-3-marcandre.lureau@redhat.com> In-Reply-To: <20220825132110.1500330-3-marcandre.lureau@redhat.com> From: Peter Maydell Date: Thu, 25 Aug 2022 14:34:16 +0100 Message-ID: Subject: Re: [PATCH 2/2] dump: fix kdump to work over non-aligned blocks To: marcandre.lureau@redhat.com Cc: qemu-devel@nongnu.org, Paolo Bonzini , qiaonuohan@cn.fujitsu.com, David Hildenbrand , Stefan Berger Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2607:f8b0:4864:20::112b; envelope-from=peter.maydell@linaro.org; helo=mail-yw1-x112b.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, 25 Aug 2022 at 14:21, wrote: > > From: Marc-Andr=C3=A9 Lureau > > Rewrite get_next_page() to work over non-aligned blocks. When it > encounters non aligned addresses, it will allocate a zero-page and try > to fill it. > > This solves a kdump crash with "tpm-crb-cmd" RAM memory region, > qemu-kvm: ../dump/dump.c:1162: _Bool get_next_page(GuestPhysBlock **, > uint64_t *, uint8_t **, DumpState *): Assertion `(block->target_start & > ~target_page_mask) =3D=3D 0' failed. > > because: > guest_phys_block_add_section: target_start=3D00000000fed40080 target_end= =3D00000000fed41000: added (count: 4) > > Fixes: > https://bugzilla.redhat.com/show_bug.cgi?id=3D2120480 > static bool get_next_page(GuestPhysBlock **blockptr, uint64_t *pfnptr, > - uint8_t **bufptr, DumpState *s) > + uint8_t **bufptr, bool *allocptr, DumpState *s= ) > { > GuestPhysBlock *block =3D *blockptr; > - hwaddr addr, target_page_mask =3D ~((hwaddr)s->dump_info.page_size -= 1); In the old code, we treated the dump_info.page size as an indication of the target's page size... > - uint8_t *buf; > + uint32_t page_size =3D s->dump_info.page_size; > + bool alloced =3D false; > + uint8_t *buf =3D NULL, *hbuf; > + hwaddr addr; > > /* block =3D=3D NULL means the start of the iteration */ > if (block =3D=3D NULL) { > *blockptr =3D block =3D QTAILQ_FIRST(&s->guest_phys_blocks.head)= ; > addr =3D block->target_start; > + *pfnptr =3D dump_paddr_to_pfn(s, addr); > } else { > - addr =3D dump_pfn_to_paddr(s, *pfnptr + 1); > + assert(block !=3D NULL); > + *pfnptr +=3D 1; > + addr =3D dump_pfn_to_paddr(s, *pfnptr); > } > assert(block !=3D NULL); > > - if ((addr >=3D block->target_start) && > - (addr + s->dump_info.page_size <=3D block->target_end)) { > - buf =3D block->host_addr + (addr - block->target_start); > - } else { > - /* the next page is in the next block */ > - *blockptr =3D block =3D QTAILQ_NEXT(block, next); > - if (!block) { > - return false; > + while (1) { > + if (addr >=3D block->target_start && addr < block->target_end) { > + size_t n =3D MIN(block->target_end - addr, page_size - addr = % page_size); > + hbuf =3D block->host_addr + (addr - block->target_start); > + if (!alloced) { > + if (n =3D=3D page_size) { > + /* this is a whole host page, go for it */ > + assert(addr % page_size =3D=3D 0); ...but here we're claiming in this comment that it is the host's page size. Which is it ? thanks -- PMM