From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 C74BF367B8A; Tue, 23 Jun 2026 09:52:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782208324; cv=none; b=E0pgLuBM6rukf0/ZKcBd6h1QVUEAyXZpH6TYKjRY84uZzPEs/qvAjUMIrI+8oV0PWWDjN5JYNzoA9Hc3PXfDj+SFq3F2UFl5z3pqvyvgkTcHcqROi8iE8bo9VGDbLbsSTCj1zj68rlBIk1dhK+c4gw2SaayXzmAZC67inLS5EfA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782208324; c=relaxed/simple; bh=EQP3s0uik6wNnCuIqMfZ1qDZ77sCf01E6eXPGrgAJjs=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=bgN6AOy+F6pXBBUwy+u50y6+moJW5VXsIN+EdihUUxTHqL5VGn7igP6eWhItoopMOte6Vc+KIhBrplnRvoUqgTrJRZ6+CMH7xGc9lDLeH3YO8TuCiUcvUOqC4OzvgsXEuYLdFrBS3ijnS1yLUmhqmlt1YLYUdlfh6CCgFv9FqxA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UhJBtUZ+; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UhJBtUZ+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 514AD1F000E9; Tue, 23 Jun 2026 09:52:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782208323; bh=XivQlvdLpY7xpybLVo/eZqqbhvnd91yNEkwRxW/Nj+0=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=UhJBtUZ+qJJgbWifFXxmwUaQmvPokIta/Q7oxVwplPk9Npvq78MCNcVdlDsq3oeqg yGc+nA1Yn6tpBEaejUqk4tme0U6/T9knWP0uj57Tk5NOmE5DVysH52W/mg4EHvppYN 3kTSresu858j8BdWotWSSX6NusI761XNiLbxWZRaHkXT0IL+n1XtsB5Mn7/LTE8ivX C10SsT4qRieh1HdzE+CqZAqA86hhzs1xzMcM0W2EfUwFgvJRtRgTjaTBZoMyhusjly 3v9SGvdBEoZu6SGZNYbf+N9uCymyEfojOgQoCF7zB3oUJkeyrO3x+f+nmmgSVWeYKW T1yCPqj6jFfOA== 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 4.98.2) (envelope-from ) id 1wbxnU-0000000FE6l-44hg; Tue, 23 Jun 2026 09:52:01 +0000 Date: Tue, 23 Jun 2026 10:52:00 +0100 Message-ID: <86v7b9r3cv.wl-maz@kernel.org> From: Marc Zyngier To: leixiang Cc: oupton@kernel.org, seanjc@google.com, pbonzini@redhat.com, kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Eric Auger Subject: Re: [RFC PATCH] KVM: arm64: Set irqfd->producer to enable vLPI routing updates In-Reply-To: <20260623081433.21250-1-leixiang@kylinos.cn> References: <20260622075103.35164-1-leixiang@kylinos.cn> <20260623081433.21250-1-leixiang@kylinos.cn> 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/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: leixiang@kylinos.cn, oupton@kernel.org, seanjc@google.com, pbonzini@redhat.com, kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, eauger@redhat.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false + Eric On Tue, 23 Jun 2026 09:14:33 +0100, leixiang wrote: > > ARM64's kvm_arch_irq_bypass_add_producer() never sets irqfd->producer, > so kvm_irq_routing_update() never calls the ARM64 routing hook. That > hook unmaps the vLPI and falls back to software injection when an > irqfd's MSI routing changes; with it dead, the vLPI stays bound to the > old translation. /confused. Why should userspace be in control of anything? There is no real "routing" involved (that's the guest's responsibility), and we are really trying to hide the fact that VLPIs are used to deliver guest-visible LPIs. Can you explain what this is achieving? Thanks, M. -- Without deviation from the norm, progress is not possible.