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 5CC191A9B32 for ; Tue, 8 Apr 2025 06:51:36 +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=1744095096; cv=none; b=TFXHenXZSQ62skdODpTLGWIC5NV5cUK9e+G0kTU9GqhfI5yNRYRzPcVGMxd2mxvNlFMJPK5kS4tO0WG2M0JjzT9yh1/ahv+hHKzM7MSqj4XO3XbkDF4YeMIEm3nl3zuu9a0h1svtyolm3RbJ1ZxWBQ6w9ESe90iShBnPxjOpNag= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744095096; c=relaxed/simple; bh=vXfDKe6A9XOONd93v6d3bmaYZpfSM7WvA/Iu2nJfXI8=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=YScNV4NQn2+OHJLe4oCOr+SdDunZ7n2U/TsXi259D2PycmYh3u7+pdXY0/+p4aJuDnmyO+DklWHswfQTllS8uddGrPHObeQJiXxNqOMWUqSLpN6Zl6Seh9jzY2yA1cRtDzh5UKsL4agbBX+WrkaFZTpGeE9+3QAhFf8nRTaP+C0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BhyV461g; 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="BhyV461g" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D65C7C4CEE5; Tue, 8 Apr 2025 06:51:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744095095; bh=vXfDKe6A9XOONd93v6d3bmaYZpfSM7WvA/Iu2nJfXI8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=BhyV461g3VDb+3omCSWZRyG7dUjFqrG9QgFnx+Vt3r4oi+BHwHj8NOKm4Ixt9aCJx IgELwBbK+eLuDu6kWKT7Tj454+gc//8567yFEMqBHeibaAyrodclrwHdn0n0VIfivf bmzMw/SZyhAfUaP/d4t5lL8dvH/JP0XLyqpzbgl0v4a/xCRrVX0UWG7ZW0lj+g8RSq 2XB1mdaf+blM5JBM9i/G3lv/eRGzhKzBvD1oDNaoEpyf/XT8/vqtUbsAUXYQdpThhN 46PN7eFFxeEP1ycmGOOw+cGOrXg+vpYY8Zi6L/HuDjVcsnPxRMERUc+z2qPm1eoKlm 2dP1rtjwxuBBw== 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 1u22o1-003JCn-7Z; Tue, 08 Apr 2025 07:51:33 +0100 Date: Tue, 08 Apr 2025 07:51:32 +0100 Message-ID: <86tt6zkux7.wl-maz@kernel.org> From: Marc Zyngier To: Donghyeok Choe Cc: Sudeep Holla , Youngmin Nam , Thomas Gleixner , Saravana Kannan , Ulf Hansson , Vincent Guittot , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-team@android.com, hajun.sung@samsung.com, joonki.min@samsung.com, ne.yoo@samsung.com Subject: Re: [GICv3 ITS]S2IDLE framework does not invoke syscore_ops in GICv3 ITS driver In-Reply-To: <20250407225146.GA2858456@tiffany> References: <8634f0mall.wl-maz@kernel.org> <20250402-messy-wild-squid-7b4da9@sudeepholla> <20250403-rare-wasp-of-management-9bce59@sudeepholla> <20250404041323.GA685160@tiffany> <20250407-amiable-perfect-hummingbird-06ad83@sudeepholla> <20250407225146.GA2858456@tiffany> 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/29.4 (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: d7271.choe@samsung.com, sudeep.holla@arm.com, youngmin.nam@samsung.com, tglx@linutronix.de, saravanak@google.com, ulf.hansson@linaro.org, vincent.guittot@linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-team@android.com, hajun.sung@samsung.com, joonki.min@samsung.com, ne.yoo@samsung.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Mon, 07 Apr 2025 23:51:46 +0100, Donghyeok Choe wrote: > > [1 ] > On Mon, Apr 07, 2025 at 10:17:43AM +0100, Sudeep Holla wrote: > > Do you use any suspend/resume logic in drivers/irqchip/irq-gic-pm.c ? > No, there are parts of the GIC that require secure access, so the > GIC save/restore is performed by the firmware. > Since the GIC-ITS is entirely controlled as a non-secure IP, > I think it is more efficient to perform save/restore in the kernel. More efficient? Give me *one* aspect of this save/restore sequence that is done in a more efficiently way in the kernel. Dumping MMIO accesses into memory has the exact same cost at EL1, El2 or EL3, and splitting things along an arbitrary line to paper over bad firmware is not a valid argument. M. -- Without deviation from the norm, progress is not possible.