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 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 DB75CC83F27 for ; Tue, 22 Jul 2025 10:45:29 +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:MIME-Version:Content-Type: References:In-Reply-To:Date:Cc:To:From:Subject:Message-ID: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=H5AJSmcCCCKNAXSqfW7sT47PDzE+5zX+eMloIpgG+9Y=; b=5DS3QYtQZhPaXHr50t/Vj7ISAk /tu7//ULXxCgcE0gkRQi/fmyg3TdzMFWS1H9gEWC/lfkowcgwroFj0L7H5wMa6/LvgAZxp2nx+N4W 9YnVXduyfjFMIGs9i8MIfPUt60IVcqWC/1SpcggCNtZ/oi2NH8xl2sAoRyQJpu9WTm8x08JlNxuO8 Mj28Gm94XWLcj2la5yGychuXS/lq892rg8yEI5m9+bbZvnP4qCRYyTuV1qDDwWA50t0fa7n426J3V Q7Xnhepk7YKI0CNGNlow0JXFxlobMN0PPg6mqEDDYzZXzg67HaghHrj/QXQ2p1AV29snnK51Shl48 2nCX8CjA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1ueAUu-00000002Bhg-0zAd; Tue, 22 Jul 2025 10:45:24 +0000 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1ueALW-00000002AdD-3xDA for linux-arm-kernel@bombadil.infradead.org; Tue, 22 Jul 2025 10:35:43 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=MIME-Version:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=H5AJSmcCCCKNAXSqfW7sT47PDzE+5zX+eMloIpgG+9Y=; b=HfGWJI3HWjYuJfbveUe/S1XZCV cEq88MJFOIev6P5ncXdqK9PY9QQZ9dzG4qWt1KsVIoocLcm993aNd0IwwcJ5EupZ+UAD14jWU4xjg PJJ9ycD/mxRjctfAdT84oChf/qImgq/keheVAkeIp4GM7yd2QCsZSvP8+0b3ev/cF1DLFOfkYnsUI 5dfg9aHSL3g0IhMkSJ4wMaNrIeiFiPWo+zIR1cQknbicMExTPXxHMHKAsMMhNqlI1e7vnOcHP3Y5P EiyTf06gnpmge1wxHZ6VOD2VG1tXILb4uUparfzZDhVi8BXk7TPfGE1ifT90GZTFeeUuNkB73RYSb 1bBP1L+Q==; Received: from [54.239.6.185] (helo=freeip.amazon.com) by casper.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1ueALV-000000091Ij-05YA; Tue, 22 Jul 2025 10:35:41 +0000 Message-ID: Subject: Re: [RFC PATCH 2/2] KVM: arm64: vgic-its: Unmap all vPEs on shutdown From: David Woodhouse To: Marc Zyngier , Oliver Upton , Joey Gouly , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Paolo Bonzini , Sebastian Ott , Andre Przywara , Thorsten Blum , Shameer Kolothum , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: "Saidi, Ali" Date: Tue, 22 Jul 2025 12:35:40 +0200 In-Reply-To: References: <20250623132714.965474-1-dwmw2@infradead.org> <20250623132714.965474-2-dwmw2@infradead.org> Content-Type: multipart/signed; micalg="sha-256"; protocol="application/pkcs7-signature"; boundary="=-lY953aquI9F2Q7urWx3t" User-Agent: Evolution 3.52.3-0ubuntu1 MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html 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 --=-lY953aquI9F2Q7urWx3t Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Mon, 2025-06-23 at 18:38 +0200, David Woodhouse wrote: > On Mon, 2025-06-23 at 14:27 +0100, David Woodhouse wrote: > > From: David Woodhouse > >=20 > > We observed systems going dark on kexec, due to corruption of the new > > kernel's text (and sometimes the initrd). This was eventually determine= d > > to be caused by the vLPI pending tables used by the GIC in the previous > > kernel, which were not being quiesced properly. >=20 > FWIW this is a previous hack we attempted which *didn't* work. (For > illustration only; ignore the syscore .kexec hook. We addressed that > differently in the end with > https://lore.kernel.org/kexec/20231213064004.2419447-1-jgowans@amazon.com= /=C2=A0) >=20 > At the point where the its_kexec() hook in this patch has completed, we > poisoned the (ex-) vLPI pending tables and then scanned for corruption > in them. We saw the same characteristic pattern of corruption which had > been breaking the next kernel after kexec: 32 bytes copied from offset > 0 to offset 32 in a page, followed by bytes 0, 1, 32, 33, 34, 35 being > zeroed. >=20 > Adding a few milliseconds of sleep before the poisoning was enough to > make the problem go away. As is the patch which calls unmap_all_vpes() > =E2=88=80 kvm. >=20 > Of course, if the GIC were behind an IOMMU as all DMA-capable devices > should be, this might never have happened... Any thoughts on this? I'd really appreciate some guidance from Arm on precisely what is *expected* of the operating system here, to quiesce the GIC correctly.=20 --=-lY953aquI9F2Q7urWx3t Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCD9Aw ggSOMIIDdqADAgECAhAOmiw0ECVD4cWj5DqVrT9PMA0GCSqGSIb3DQEBCwUAMGUxCzAJBgNVBAYT AlVTMRUwEwYDVQQKEwxEaWdpQ2VydCBJbmMxGTAXBgNVBAsTEHd3dy5kaWdpY2VydC5jb20xJDAi BgNVBAMTG0RpZ2lDZXJ0IEFzc3VyZWQgSUQgUm9vdCBDQTAeFw0yNDAxMzAwMDAwMDBaFw0zMTEx MDkyMzU5NTlaMEExCzAJBgNVBAYTAkFVMRAwDgYDVQQKEwdWZXJva2V5MSAwHgYDVQQDExdWZXJv a2V5IFNlY3VyZSBFbWFpbCBHMjCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAMjvgLKj jfhCFqxYyRiW8g3cNFAvltDbK5AzcOaR7yVzVGadr4YcCVxjKrEJOgi7WEOH8rUgCNB5cTD8N/Et GfZI+LGqSv0YtNa54T9D1AWJy08ZKkWvfGGIXN9UFAPMJ6OLLH/UUEgFa+7KlrEvMUupDFGnnR06 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