From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E06E87764C for ; Wed, 24 Jan 2024 12:43:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706100233; cv=none; b=ZmQEhXfqQiKR4qFS7kBz3sDKp+6On6y7d+nIrBtlsS+QmYU6PNiZcmiw8LHnw5vwu1Yubbw/9oH8EBWJzwjaxPZmffjeaL+If9XWXW1fvNH+vjTlSrbuiAmDSmcJK+UvIC3XYpC1AjYBXacW8zDq3vwISCwdCA7v415leWOkdes= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706100233; c=relaxed/simple; bh=u0vGJxROrhTS4kvxwqHLUVg+IUg+Xi7vcEAgXmfVwUE=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=RtpSoCtQ4ieqPaWsaFklfN1TAZrEEQ+wSFcAa/TQZJqVdBW3Cpv5yTE62VzTPvr6yGtEqVJNmNtzrgrffCQB3RgQVVmKOrNXohro4jqCfIHQXzTwaKQPA4lhc/6xywC5UqSbeGSNReXQKDW3gN4GKcutjcCx5xS871kIvv5kQxE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iCObavxx; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="iCObavxx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 62F43C43394; Wed, 24 Jan 2024 12:43:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1706100232; bh=u0vGJxROrhTS4kvxwqHLUVg+IUg+Xi7vcEAgXmfVwUE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=iCObavxxxmKdtvxEzY67nCBlj8UkQtjh4inrVSK2GeO6RQk7T89kc+N1bGiAk7VwJ MOvlm8LE2Jcl7wVnpnZwTLY70WqNrq5Sn1c3fIvBNLZ8TNzu8mliCmiTJX8G1VmFOb U7wKZBfTW18T0lI33y5yfiBqFnLet8sygmZPdbpPJdeNFXrnagsUA6VSaw0eEaBVR8 2OOMv3YlAqJK7EMjgOxukA5thN03kM7Z/UpUtrI29t0f4KmliELDrJ/ll68zm0yQ3f 0AY1IIo2IB1aH+SNxbGF3eoXtzrsfdkMpv0HrgVFMKehfYTs5hxGYXWHAsIqDbkv1A PpSuApSedpdTw== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1rScbc-00EKMi-TN; Wed, 24 Jan 2024 12:43:50 +0000 Date: Wed, 24 Jan 2024 12:43:48 +0000 Message-ID: <86cytq9a0r.wl-maz@kernel.org> From: Marc Zyngier To: Kunkun Jiang Cc: Oliver Upton , James Morse , Suzuki K Poulose , Zenghui Yu , moderated for non-subscribers , , "wanghaibin.wang@huawei.com" Subject: Re: [bug report] GICv4.1: doorbell interrupts will be lost in a corner case In-Reply-To: <4edc4d02-5c0b-a2e5-897a-7e60fbb0f3e3@huawei.com> References: <4edc4d02-5c0b-a2e5-897a-7e60fbb0f3e3@huawei.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/29.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: jiangkunkun@huawei.com, oliver.upton@linux.dev, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, wanghaibin.wang@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Wed, 24 Jan 2024 08:54:24 +0000, Kunkun Jiang wrote: >=20 > Hi all=EF=BC=8C >=20 > In chapter 8.5 ("Doorbells") of the GIC spec, the affinity of > doorbell interrupt is described like this: >=20 > > Doorbell interrupts target the Redistributor the vPE is > > currently mapped to, based on the previous VMAPP or VMOVP > > command for the vPE. > The doorbell interrupt here should refer to all types of > doorbell interrupt, right? There is only one type of doorbell. >=20 > When GICv4.1 is enabled, the doorbell interrupt will be > truned on only when kvm handles WFI exit. There is a > corner case where will lost doorbell interrupt: > 1. doorbell interrupt enabled > 2. the cpu which the vPE is mapped to is manually offline > =C2=A0 through 'echo 0 > /sys/device/system/cpu/cpuX/online' > 3. According to the description of chapter 8.5 ("Doorbells"), > =C2=A0 the doorbell interrupt coming at this time will still > =C2=A0 be sent to the offline cpu.Then the interrupt will be > =C2=A0 lost. >=20 > Should we add a cpu offline callback to handle the > doorbell interrupt mapped to this cpu? That seems gross. The right way to do it is to track the affinity of the doorbell (which we already do), and let the core code move the interrupt somewhere else in this case (which is should already do). Have you actually witnessed this issue? Or is that just idle conjecture? M. --=20 Without deviation from the norm, progress is not possible. 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Wed, 24 Jan 2024 12:43:50 +0000 Date: Wed, 24 Jan 2024 12:43:48 +0000 Message-ID: <86cytq9a0r.wl-maz@kernel.org> From: Marc Zyngier To: Kunkun Jiang Cc: Oliver Upton , James Morse , Suzuki K Poulose , Zenghui Yu , moderated for non-subscribers , , "wanghaibin.wang@huawei.com" Subject: Re: [bug report] GICv4.1: doorbell interrupts will be lost in a corner case In-Reply-To: <4edc4d02-5c0b-a2e5-897a-7e60fbb0f3e3@huawei.com> References: <4edc4d02-5c0b-a2e5-897a-7e60fbb0f3e3@huawei.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/29.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: jiangkunkun@huawei.com, oliver.upton@linux.dev, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, wanghaibin.wang@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); 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