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 464A140F751; Mon, 14 Sep 2026 08:38:20 +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=1789375104; cv=none; b=JI7+5sd93shZmthlh9MM8vOh0qus8+UZKJXIXcWpWYhGIGTvdtxRKvNFEz+houa7WMVXGSg74FxjsordrwfCRkAGY3OOdQ/b0SP3+2qSudrPmmvQLqbXj38uTOVBY7suNMzZGjRXbJUv3FVgxf1vHpdWH+4r/ReIS9wTqUeWx7c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789375104; c=relaxed/simple; bh=44Zxr0bAzy/FVaHYHhpGrc8BaI6/0sVp1yPuJiyTLok=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Mx2hqgMCFGgREh4ZpClTBbxKMsaAWUxcghAVeiXTG5ewcChXAypOEul2Hl5xVZ/QMkcH8GGddY3H+xeVfSnl3w6U5xM0oSjkfvqp/e0L+mKBhkxfjW9aTWs+Z2CH/ig04tz2YiSiEK9GTuninRzZv0CdmKng0DME2Cal2bu12qk= 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=trDYbUBd; 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="trDYbUBd" 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 BFD041570; Mon, 14 Sep 2026 01:38:15 -0700 (PDT) Received: from [10.0.128.139] (unknown [10.0.128.139]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CD7EC3F7B4; Mon, 14 Sep 2026 01:38:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1789375099; bh=44Zxr0bAzy/FVaHYHhpGrc8BaI6/0sVp1yPuJiyTLok=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=trDYbUBd8UJwtxnr5vASuBR49N08Qhrp+erecALsuVHO5qeuyeEwlNO1jTQ9dzICy 5RBCJaUgzOIw888gkG3fO+hInEVEOdJFYEAqqhFfwfoUUcwZoBACn0bOu1n6gl1/G9 M/9oFTHq4omPIvlpXxn5YpbUoMmFgSEg5bpJPIF0= Message-ID: Date: Mon, 14 Sep 2026 09:38:15 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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: Gavin Shan , kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: 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, 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> From: Suzuki K Poulose In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 14/09/2026 06:41, Gavin Shan wrote: > On 9/12/26 6:36 PM, 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. >> >> 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 >> --- >>   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 ecc89e91d264d..583e1aca9b15a 100644 >> --- a/drivers/firmware/arm_rmm/rmi.c >> +++ b/drivers/firmware/arm_rmm/rmi.c >> @@ -5,12 +5,15 @@ >>   #include >>   #include >> +#include >>   #include >>   #include >>   #include >>   #include >> +static bool arm64_rmi_is_available; >> + >>   /* Currently only the first 2 registers are used by Linux */ >>   #define RMI_FEAT_REG_COUNT    2 >>   static unsigned long rmi_feat_reg_cache[RMI_FEAT_REG_COUNT] >> __ro_after_init; >> @@ -68,6 +71,69 @@ static inline long >> rmi_granule_range_undelegate(unsigned long base, >>       return ret; >>   } >> +/** >> + * rmi_granule_tracking_get() - Get configuration of a Granule >> tracking region >> + * @start: Base PA of the tracking region >> + * @end: End of the PA region >> + * @out_category: Memory category >> + * @out_state: Tracking region state >> + * @out_top: Top of the memory region >> + * >> + * Return: RMI return code >> + */ >> +static inline int rmi_granule_tracking_get(unsigned long start, >> +                       unsigned long end, >> +                       unsigned long *out_category, >> +                       unsigned long *out_state, >> +                       unsigned long *out_top) >> +{ >> +    struct arm_smccc_1_2_regs regs = { >> +        SMC_RMI_GRANULE_TRACKING_GET, start, end, >> +    }; >> + >> +    rmi_smccc_invoke(®s); >> + >> +    if (regs.a0 != RMI_SUCCESS) >> +        return regs.a0; >> + >> +    if (out_category) >> +        *out_category = regs.a1; >> +    if (out_state) >> +        *out_state = regs.a2; >> +    if (out_top) >> +        *out_top = regs.a3; >> + >> +    return RMI_SUCCESS; >> +} >> + >> +/* >> + * rmi_gpt_info - Query the GPT info for the given PAR. >> + * @start: Base of the physical address region >> + * @top: Top of the physical address region >> + * @out_top: Top of the phyiscal address region for which >> + *        the GPT @out_gpt_par_state is valid >> + * @out_gpt_par_state: State of the GPT covered by [start, out_top) >> + */ >> +static inline long rmi_gpt_info(unsigned long start, unsigned long end, >> +                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; >> +} >> + >>   /** >>    * rmi_features() - Read feature register >>    * @index: Feature register index >> @@ -759,6 +825,124 @@ static int rmi_configure(void) >>       return ret; >>   } >> +/* >> + * Make sure the area is tracked by RMM at FINE granularity. >> + * We do not support changing the tracking yet. >> + */ >> +static int rmi_verify_memory_tracking(phys_addr_t start, phys_addr_t >> end) >> +{ >> +    while (start < end) { >> +        unsigned long ret, category, state, next; >> + >> +        ret = rmi_granule_tracking_get(start, end, &category, &state, >> &next); >> +        if (ret != RMI_SUCCESS) >> +            return -ENOMEM; >> + >> +        if (state != RMI_TRACKING_FINE || >> +            category != RMI_MEM_CATEGORY_CONVENTIONAL) { >> +            /* TODO: Set granule tracking in this case */ >> +            pr_err("Granule tracking for region isn't fine/ >> conventional: %llx-%lx\n", >> +                   start, next); >> +            return -ENODEV; >> +        } >> +        start = next; >> +    } >> + >> +    return 0; >> +} >> + > > I would suggest to drop rmi_granule_tracking_get() by combining its > logics into > rmi_verify_memory_tracking(). > > /* >  * Make sure the area is tracked by RMM at FINE granularity. >  * We do not support changing the tracking yet. >  */ > static int rmi_verify_memory_tracking(phys_addr_t start, phys_addr_t end) > { >         struct arm_smccc_1_2_regs args; > >         while (start < end) { >                 args.a0 = SMC_RMI_GRANULE_TRACKING_GET; >                 args.a1 = start; >                 args.a2 = end; >                 rmi_smccc_invoke(&args); > >                 if (args.a0 != RMI_SUCCESS) >                         return -ENOMEM; > >                 if (args.a1 != RMI_MEM_CATEGORY_CONVENTIONAL || >                     args.a2 != RMI_TRACKING_FINE) { >                         /* TODO: Set granule tracking in this case */ >                         pr_err("Granule tracking for region isn't fine/ > conventional: %llx-%lx\n", >                                 start, args.a3); >                         return -ENODEV; I have moved the wrappers closer to the caller, but retained them to make it easier to read the code. e.g., error conditions around next >= start etc. >                 } > >                 start = args.a3; >         } > >         return 0; > } ... > > I would suggest to drop rmi_gpt_info() by combining its logics into > rmi_verify_gpt_firmware_managed(). > Same as above. >> + >> +static int rmi_init_metadata(void) >> +{ >> +    phys_addr_t start, end; >> +    struct memblock_region *r; >> + >> +    for_each_mem_region(r) { >> +        int ret; >> + >> +        /* Firmware-reserved NOMAP regions are not usable system RAM */ >> +        if (memblock_is_nomap(r)) >> +            continue; >> + >> +        start = memblock_region_memory_base_pfn(r) << PAGE_SHIFT; >> +        end = memblock_region_memory_end_pfn(r) << PAGE_SHIFT; >> + > > nit: unnecessary to covert the physical address (struct > memblock_region::base and (base + size)) > to PFN and then convert PFN to physical address: > >         start = PAGE_ALIGN(r->base); >         end = PAGE_ALIGN_DOWN(r->base + r->size); >         if (start >= end) >             continue; Yes, I have handled this already per Sashiko review comment. Thank you for the review! Cheers Suzuki