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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0979EC982DE for ; Mon, 21 Sep 2026 09:33:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=TmdEjNT3QsvLxGFQxg1V+0Owxm6zG0u/XRcs38Q6LjM=; b=dotOIexmGb9YRqdJ5o4HTFWzzK 4X8lNNiZ4MEfte6Yn8/XZGyBSggnAqN/e+WDLHlui3P3dT/3B/AeHP4y+aowqRShONeJUNh/5gebp aP7vdvXqWD+cXaOW2UXY5o/Jd6FUt8l/pPRroLYGkj4ufH3rnnUbpN94c/j4qkFbzbh23H9VajYQn qv8CAzjSfazgkwwbiid18zHcU/rL3hWTd1lqtj5wI52ItEEQolAxoRXRCwymzBC1KGXm+8CMxBbi7 IaO6kjIjFGuREOoC5ixO0aCsqAVhH1yzshQkNSmwHrjIzUSjo8i+q4tuhp6CiXlyOhdTEk6/NOXxk iI12JtIg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x8aOY-00000001WtH-2aSg; Mon, 21 Sep 2026 09:33:07 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x8aOV-00000001WsC-2oZK for linux-arm-kernel@lists.infradead.org; Mon, 21 Sep 2026 09:33:04 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id EAEA61476; Mon, 21 Sep 2026 02:32:58 -0700 (PDT) Received: from [10.0.128.141] (unknown [10.0.128.141]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 28C9B3F86F; Mon, 21 Sep 2026 02:32:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1789983182; bh=B+BCQeVg0IeeUhu6Ob/UgCt/CZY7OCEK8gMHWMyBohk=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=vrTxUkU5EokJyM+O6vocnZOre+9Hm/zL/psZb2j5wq0ib0aPS77g8TxaTl+R6pBo7 vxkpDKVN4HocH01hrrylZzzdL9upfpdvpXEealrDA1Ba5SMWmFOqqaqVjfxjeLR5jt DSNnAGCwoigCPtBiotCwuNvfddJajT2mvtAGQIxM= Message-ID: <65b0c03b-36b9-4e60-aa55-c3b4b85e21ee@arm.com> Date: Mon, 21 Sep 2026 10:32:57 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v18 6/7] firmware: arm_rmm: Ensure the RMM has GPT entries for memory Content-Language: en-GB To: Jonathan Cameron Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, maz@kernel.org, will@kernel.org, catalin.marinas@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, steven.price@arm.com, aneesh.kumar@kernel.org, oupton@kernel.org, gshan@redhat.com, joey.gouly@arm.com, tabba@google.com, yuzenghui@huawei.com, linux-coco@lists.linux.dev, gankulkarni@os.amperecomputing.com, sdonthineni@nvidia.com, alpergun@google.com, fj0570is@fujitsu.com, WeiLin.Chang@arm.com, lpieralisi@kernel.org, enju.kohei@fujitsu.com References: <20260912083611.2513845-1-suzuki.poulose@arm.com> <20260912083611.2513845-7-suzuki.poulose@arm.com> <178978126543.2352296.12214136703168879825.b4-review@b4> From: Suzuki K Poulose In-Reply-To: <178978126543.2352296.12214136703168879825.b4-review@b4> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260921_023303_794318_766BEE24 X-CRM114-Status: GOOD ( 27.94 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 19/09/2026 02:27, Jonathan Cameron wrote: >> The RMM maintains the state of all the granules in the system to make >> sure that the host is abiding by the rules. This state can be maintained >> at different granularity, per page (TRACKING_FINE) or per region >> (TRACKING_COARSE or TRACKING_INTERMEDIATE). The region size depends on the >> underlying "RMI_GRANULE_SIZE". For a "coarse"/"intermediate" region, all pages >> in the region must be of the same state, this implies we need to have "fine" >> tracking for DRAM, so that we can delegate individual pages. >> >> For now we only support a statically carved out memory for tracking >> granules for the "fine" regions. This can be extended in the future to >> allow modifying the tracking granularity and remove the need for a >> static allocation by the firmware. >> >> Similarly, the firmware may create L0 GPT entries describing the total >> address space. But if we change the "PAS" (Physical Address Space) of a >> granule, then the firmware may need to create L1 tables to track the PAS >> at a finer granularity. Linux therefore checks if the platform firmware manages >> the PAR region. i.e., the firmware is in charge of managing the L1 GPTs >> (creation and the required memory for the GPT tables - via static carveouts) >> without host intervention. Support for dynamic GPT creation by the host will be >> added later. >> >> If the firmware requires us to manage the tracking or GPT memory, Deactivate >> the RMM and reclaim any memory donated at RMM activation. >> >> Apply the same checks when hotplugged memory is brought online. >> >> Signed-off-by: Steven Price >> [ Switch to RMI_GPT_L1_INFO for checking GPTs and deactivate RMM ] >> Co-Developed-by: Suzuki K Poulose >> Signed-off-by: Suzuki K Poulose > > A few comments inline. > > >> --- >> Changes since v17: >> * Move wrappers that may not be used elsewhere, out of arm-rmi-cmds.h >> Changes since v16: >> * Check fine tracking and create L1 GPTs for hotplug-added memory. >> * Clarify the L1 GPT setup and move the explanatory comment. >> * Switch to using RMI_GPT_INFO command for checking the GPTs. >> * Deactivate the RMM and reclaim the memory if we can't proceed. >> Changes since v15: >> * Skip firmware-reserved NOMAP memory in rmi_init_metadata() >> * Handle negative error codes from wrappers. >> Changes since v14: >> * Move the implementation into drivers/firmware/arm_rmm. >> Changes since v13: >> * Moved out of KVM >> --- >> drivers/firmware/arm_rmm/rmi.c | 200 +++++++++++++++++++++++++++++++++ >> include/linux/arm-rmi-cmds.h | 2 + >> 2 files changed, 202 insertions(+) >> >> diff --git a/drivers/firmware/arm_rmm/rmi.c b/drivers/firmware/arm_rmm/rmi.c >> index ecc89e91d264..583e1aca9b15 100644 >> --- a/drivers/firmware/arm_rmm/rmi.c >> +++ b/drivers/firmware/arm_rmm/rmi.c > > >> + */ >> +static inline long rmi_gpt_info(unsigned long start, unsigned long end, > > Why inline vs letting compiler make it's mind up? > Same in other places > >> + unsigned long *out_top, >> + unsigned long *out_gpt_par_state) >> +{ >> + struct arm_smccc_1_2_regs regs = { >> + SMC_RMI_GPT_INFO, start, end, >> + }; >> + >> + rmi_smccc_invoke(®s); >> + if (regs.a0 != RMI_SUCCESS) >> + return regs.a0; >> + >> + if (out_top) >> + *out_top = regs.a1; >> + if (out_gpt_par_state) >> + *out_gpt_par_state = regs.a2; >> + >> + return RMI_SUCCESS; >> +} > > > >> static int __init arm64_init_rmi(void) >> { >> int ret; >> @@ -786,8 +970,24 @@ static int __init arm64_init_rmi(void) >> if (ret) { >> pr_err("RMM activate failed\n"); >> ret = ret < 0 ? ret : -ENXIO; >> + return ret; > > Why did this change? Rebase messed up. I will restore it. > >> } >> >> + ret = rmi_init_metadata(); >> + if (ret) > > And this is hitting another bit of guidance in cleanup.h. > Functions shouldn't be mixing __free and friends with > gotos. Again, not a bug here but there are large ugly > monsters around this stuff, hence the blanket guidance. > I haven't thought that hard on how you avoid it here, but > usually it's a combination of suitable helpers and wrappers > and resulting code is often more readable as a result. > I will see if I can improve it. Cheers Suzuki