From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794521981; b=a6p94EfdJaKTbsLVbJyJnP00VwSv6pA5/wtJJgIQcP6ic362XwrFSaUXVmF2UYN5XIE8 fA/mEQsB6qj9dB8bTOj5AHVHgt160qqB0zmM7bF+w8PZTw96BJheXsFx3U6t3TA0Uqz3m 6kBWmYVQarhpRNfrkPg5uerWGs7AVJ4hlMDHVyOu35U3AW5rs7qfcVmdSduFwwrJlRw7P mSk0xP2kEq0pV/ykuLNw49cShRoZ4oIc6fANuixJtrmuz1pr2o89TN6eRDJ2Kd/BLv7lm gB79UA7brlQMa0YfTDbg73vWYd3Tn0haXvZAjL8hMWt4iyO6Hbfl073puMMph8b0cnQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794521981; h=Received:DKIM-Signature:Received:Date:Message-ID:From:To:Cc:Subject: In-Reply-To:References:User-Agent:MIME-Version:Content-Type: X-SA-Exim-Connect-IP:X-SA-Exim-Rcpt-To:X-SA-Exim-Mail-From: X-SA-Exim-Scanned; bh=MdFOkR9T1vyvJTEbm/GmyrakOZfYhcZ9ZgO9mPMwqgE=; b=N4eGRyHzaLSeWnyH93Tbvyy71kSqiLbwFpgp4kB5jL+bkknBhbPbBGoV3/VLcEmTMh8g 3FUkoBs6/JHYFV0kTDEY3v8r3aanmzDxU1w4Kaw9Ze0/qpmNgpxI1w2fbDizu0HtxaRuw NMAQR8/jxuiajfliFJGIGp9pOIo76ZCnDf0juYZVeFRziVk361sfsESD8jTwd/vRicBWs YHYUurI0W9XHdp8TKlLS4r63tr7lzD3vVRg9vm1ZRxOfj5qvpxrr6yK57ovwzJ9IfVWdm j+Ohpvvx+wMIlFIYU6SkRjmQV3SObF+F8sl94U2/jf7TPF18HutDqPwYUmlzQhISfSw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=KkJPMBad; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A6BE1606A31C; Thu, 12 Nov 2026 22:19:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=KkJPMBad Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3A31C1F000C4; Thu, 12 Nov 2026 22:19:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794521981; bh=MdFOkR9T1vyvJTEbm/GmyrakOZfYhcZ9ZgO9mPMwqgE=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=KkJPMBadtLEVv4ypOglQwOiufTUuvQXpZInKdUsDfVLX5m16RASaLRZGF3Pfpwq5k Z3l76XFR6I6l2Ruv8Kj3Nwk4AFyFkGuK9xYfnJeQQTscKJVWq3zctGaoNQdWQbyQZM JTfhw6EKmkNKKAx4UaeNOGU3vdAc9pBpcDvKS3OVMw3C+ZTuYa3o9nolv7dXk4a7kM FNCFi6+G/UdRgo8wHU+FMyG3JGJMXBoJe6ln/FqhEDt8uoLumgEFgCtVUE6ufwZEUz 22ZFh7iknY4Ssw62qkkSZGpWu/c5KtAOmDmY1R2c/TjcUPFbtZo/AbBjdVW5PwfokN nqgy8nw1bs8qA== Received: from sofa.misterjones.org ([185.219.108.64] helo=lobster-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 1xRd8r-0000000F2ee-31UM; Thu, 12 Nov 2026 22:19:38 +0000 Date: Thu, 12 Nov 2026 22:22:52 +0000 Message-ID: <87ld6x8zb7.wl-maz@kernel.org> From: Marc Zyngier To: Aneesh Kumar K.V Cc: linux-coco@lists.linux.dev, Andrew Morton , Baoquan He , Mike Rapoport , Pasha Tatashin , Pratyush Yadav , Catalin Marinas , Christian =?UTF-8?B?S8O2bmln?= , Jason Gunthorpe , Joerg Roedel , Marek Szyprowski , Robin Murphy , Steven Price , Sumit Semwal , Suzuki K Poulose , Thomas Gleixner , Will Deacon , Russell King , Benjamin Gaignard , Brian Starkey , John Stultz , Mark Rutland , Radu Rendec , "T.J. Mercier" , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Ritesh Harjani , Shrikanth Hegde , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Kiryl Shutsemau , Rick Edgecombe , "K . Y . Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li , Paolo Bonzini , Vitaly Kuznetsov , Andy Lutomirski , Peter Zijlstra , dri-devel@lists.freedesktop.org, iommu@lists.linux.dev, linaro-mm-sig@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org, linux-mm@kvack.org, kvmarm@lists.linux.dev, patches@lists.linux.dev Subject: Re: [PATCH v9 14/14] irqchip/gic-v3-its: Preallocate VPE L1 tables In-Reply-To: References: <20261104164555.3555725-1-aneesh.kumar@kernel.org> <20261104164555.3555725-15-aneesh.kumar@kernel.org> <86zevn1c9a.wl-maz@kernel.org> 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) X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list 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: aneesh.kumar@kernel.org, linux-coco@lists.linux.dev, akpm@linux-foundation.org, baoquan.he@linux.dev, rppt@kernel.org, pasha.tatashin@soleen.com, pratyush@kernel.org, catalin.marinas@arm.com, christian.koenig@amd.com, jgg@ziepe.ca, joro@8bytes.org, m.szyprowski@samsung.com, robin.murphy@arm.com, steven.price@arm.com, sumit.semwal@linaro.org, suzuki.poulose@arm.com, tglx@kernel.org, will@kernel.org, linux@armlinux.org.uk, benjamin.gaignard@collabora.com, Brian.Starkey@arm.com, jstultz@google.com, mark.rutland@arm.com, radu@rendec.net, tjmercier@google.com, maddy@linux.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com, chleroy@kernel.org, ritesh.list@gmail.com, sshegde@linux.ibm.com, agordeev@linux.ibm.com, gerald.schaefer@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, kas@kernel.org, rick.p.edgecombe@intel.com, kys@microsoft. com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, longli@microsoft.com, pbonzini@redhat.com, vkuznets@redhat.com, luto@kernel.org, peterz@infradead.org, dri-devel@lists.freedesktop.org, iommu@lists.linux.dev, linaro-mm-sig@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org, linux-mm@kvack.org, kvmarm@lists.linux.dev, patches@lists.linux.dev X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Fri, 06 Nov 2026 15:45:29 +0000, Aneesh Kumar K.V wrote: > > Marc Zyngier writes: > > > On Wed, 04 Nov 2026 16:45:55 +0000, > > "Aneesh Kumar K.V (Arm)" wrote: > >> > >> VPE L1 tables are allocated from the CPU-starting callback, where sleeping is > >> not allowed. Remove the page allocation from this atomic path. > >> > >> Use a blocking allocation for the boot CPU and record the resulting table > >> order. Allocate a page of that order from the sleepable CPU hotplug prepare > >> stage for each secondary CPU. Consume the preallocated page only when the CPU > >> cannot inherit an existing redistributor or ITS table. > >> > >> Reclaim unused preallocations after the CPU reaches the online state, and from > >> the prepare-state teardown when CPU bring-up aborts. > > > > No. The way to do it is to move the ITS probing out of the > > non-sleepable CPU hotplug path. > > > > I proposed a potential hack at [1] (which I find far more palatable > > than this proposal), but the real fix is to probe the ITSs as > > devices. > > > > Could you share a bit more detail on what you have in mind? > > Are you suggesting that we create a platform device for each ITS and > initialize it through the driver's probe callback, while the rest of the > GIC initialization stays in the existing early boot path? > > Would that mean the main GIC is operational during early boot, while > ITS-dependent features, such as MSI delivery and direct injection, become > available after the ITS devices probe? > > Is that the split you have in mind? Yes. Then once this is done, all the tables become normal DMA allocations, for which there should already be adequate support. M. -- Jazz isn't dead. It just smells funny.