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 mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB9B4C433EF for ; Wed, 2 Mar 2022 07:46:51 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 1E11649DED; Wed, 2 Mar 2022 02:46:51 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); dkim=softfail (fail, message has been altered) header.i=@kernel.org Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id MCVi3F4hc0Vk; Wed, 2 Mar 2022 02:46:50 -0500 (EST) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id F292F49E22; Wed, 2 Mar 2022 02:46:49 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id E9AD649DED for ; Wed, 2 Mar 2022 02:46:48 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id CCNr-PRDLqdy for ; Wed, 2 Mar 2022 02:46:47 -0500 (EST) Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 94FB04966F for ; Wed, 2 Mar 2022 02:46:47 -0500 (EST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 09585B81F1D; Wed, 2 Mar 2022 07:46:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A3297C340EF; Wed, 2 Mar 2022 07:46:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1646207204; bh=saY4uFacqmTSqZECGMkmCoPAAs90t/+LOjZSwwOwbOs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=ADExU80jY0rCuB1MLxUsZbsn2dmH1n/N7E8zpyl2JnH93MaN8Q5ol/fmRPgUsmc2T avv7Uo44zr8igfL2hCz8WrnE396s23ZKOjSWgEo3xPmkfsLp31XbAdezPOWqH1alTw hVyNKN02A/lBCyhc9mto47EraNfvWJpPpuOCGIg6cIh66GJ8aUgvJq6aAyU9pm0ayl VkR9dwE042ukx+SD8foK1q9DsH0dmkpWX8MCNmjWn0Tfbwr6FrVmKO5vBocVrRnrjC +dJ0k6mgIqsM+LYxDOhcNDRQs8tZuUqukTNLqrLBAdmWIuQRWjKfMbZmduLx0nuify Ph/Lt18XMf1wg== Received: from ip-185-104-136-29.ptr.icomera.net ([185.104.136.29] helo=billy-the-mountain.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1nPJh3-00BbhG-UP; Wed, 02 Mar 2022 07:46:42 +0000 Date: Wed, 02 Mar 2022 07:46:35 +0000 Message-ID: <87v8ww6bl0.wl-maz@kernel.org> From: Marc Zyngier To: Kalesh Singh Subject: Re: [PATCH v4 2/8] KVM: arm64: Introduce pkvm_alloc_private_va_range() In-Reply-To: <20220225033548.1912117-3-kaleshsingh@google.com> References: <20220225033548.1912117-1-kaleshsingh@google.com> <20220225033548.1912117-3-kaleshsingh@google.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/27.1 (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: 185.104.136.29 X-SA-Exim-Rcpt-To: kaleshsingh@google.com, will@kernel.org, qperret@google.com, tabba@google.com, surenb@google.com, kernel-team@android.com, james.morse@arm.com, alexandru.elisei@arm.com, suzuki.poulose@arm.com, catalin.marinas@arm.com, mark.rutland@arm.com, broonie@kernel.org, mhiramat@kernel.org, pcc@google.com, madvenka@linux.microsoft.com, ascull@google.com, pbonzini@redhat.com, ardb@kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Cc: linux-arm-kernel@lists.infradead.org, will@kernel.org, Peter Collingbourne , kernel-team@android.com, linux-kernel@vger.kernel.org, kvmarm@lists.cs.columbia.edu, "Madhavan T. Venkataraman" , Mark Brown , Masami Hiramatsu , Catalin Marinas , Paolo Bonzini , surenb@google.com X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Fri, 25 Feb 2022 03:34:47 +0000, Kalesh Singh wrote: > > pkvm_hyp_alloc_private_va_range() can be used to reserve private VA ranges > in the pKVM nVHE hypervisor (). Also update __pkvm_create_private_mapping() > to allow specifying an alignment for the private VA mapping. > > These will be used to implement stack guard pages for pKVM nVHE hypervisor > (in a subsequent patch in the series). > > Credits to Quentin Perret for the idea of moving > private VA allocation out of __pkvm_create_private_mapping() > > Signed-off-by: Kalesh Singh > --- > > Changes in v4: > - Handle null ptr in pkvm_alloc_private_va_range() and replace > IS_ERR_OR_NULL checks in callers with IS_ERR checks, per Fuad > - Fix kernel-doc comments format, per Fuad > - Format __pkvm_create_private_mapping() prototype args (< 80 col), per Fuad > > Changes in v3: > - Handle null ptr in IS_ERR_OR_NULL checks, per Mark > > Changes in v2: > - Allow specifying an alignment for the private VA allocations, per Marc I probably badly expressed my earlier concern. Yes, an alignment is necessary. But how often do we want an alignment that isn't naturally aligned to the size of the allocation (i.e. the power of 2 >= the size of the allocation)? This is what the rest of the kernel does (get_order() and co), and I thing we should follow this. This applies to both this patch and the previous one. Thanks, M. -- Without deviation from the norm, progress is not possible. _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm