From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 6A9144FE2F7; Wed, 30 Sep 2026 13:39:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790775578; cv=none; b=OcPbDUwmFqKWe7k6mJRrpeF46BVLTauGvywM2wxlXK+2UwpS4YyRRA+1LR1zF7sZzO9+TqMiIFwXIxHDaltVeTFx5X9oJP3GSaQlHHzhVRMrAYHvd6ZSUIbfcNGHIit9cVklQ+C6BuVw5KPrCX7JHLYXAOtnPxqv/Z0/ycOvS7A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790775578; c=relaxed/simple; bh=WrLZ5gfj597SIIguCgOUtqlPTHgYb9tcuWrI/gHAH10=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=J2pLqmB+f6EGabl3uSkTD5BEG5H5l/OtzfePNCKF1LlXgOtg+G5PzQlYpZoX9UnAb0lMazdtYJThjtFGaaqOZu+LTM9IezmshmmQDNAF12SIMVKU8fEycjtz3iDnkKiFJgOVb1FTDNFou7+N5qT5QkU8HtOXd564Dkr9q4PnYm0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=Pcj3sxhu; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="Pcj3sxhu" 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 08061497; Wed, 30 Sep 2026 06:39:12 -0700 (PDT) Received: from arm.com (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1B1893F86F; Wed, 30 Sep 2026 06:39:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1790775555; bh=WrLZ5gfj597SIIguCgOUtqlPTHgYb9tcuWrI/gHAH10=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Pcj3sxhuzrhm1E/ig/tQbFU+vGp68EdZ3hS1A4ER37ixvE4v7iH8lKDH1EWxVDw4P q+VI/Tvjrv3VA4weqNAi0Sk4uHAMzZk+rQoW1zI+4kSSTimnPuEZWd4Op4GrayP4c0 6U0s8zjk3oI005UNqWKJnYD8xBQpRrTB5+UdNchM= Date: Wed, 30 Sep 2026 14:39:04 +0100 From: Catalin Marinas To: Suzuki K Poulose Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, maz@kernel.org, will@kernel.org, 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, sudeep.holla@arm.com, jonathan.cameron@oss.qualcomm.com Subject: Re: [PATCH v20 6/9] firmware: arm_rmm: Ensure the RMM has GPT entries for memory Message-ID: References: <20260929221623.1342076-1-suzuki.poulose@arm.com> <20260929221623.1342076-7-suzuki.poulose@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260929221623.1342076-7-suzuki.poulose@arm.com> On Tue, Sep 29, 2026 at 11:16:20PM +0100, Suzuki K Poulose wrote: > From: Steven Price > > 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. > > Reviewed-by: Jonathan Cameron > Reviewed-by: Gavin Shan > Tested-by: Gavin Shan > Signed-off-by: Steven Price > Co-developed-by: Suzuki K Poulose > Signed-off-by: Suzuki K Poulose Reviewed-by: Catalin Marinas