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 CAE8CC433F5 for ; Thu, 25 Nov 2021 11:43:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:Cc:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=bfKzGChnL2M54Qy3wNEMXvqaSwF3lhy32PAMEBGSU5Y=; b=ZfmWIxezkOw/beQ9xiburDvsDw q+UfUx7Pwk3zjZxfFZMvSbl+POWxG5HM25L2G0MIdj8Yq8i4oC05wdKAPXYW+FkUxAzd/8FJI6kBQ hKxKSpW5R61GtevpTHajz4DfyxjkUBpE9yKwwsAVVUVfxficIBcNsdFxlATcf8KvYfl4xecVKaiAT Q5eMv3727BdkGAg0eQu/+CVhFWfuGQ7qCRV26Z+DzMNbGmjbvLtWSI/2o1g700QGLRp7j0ayQk6bY qGb9ccI+SciC2JNmr5/SaUQy/t90G+r4e5FizqUOpXKAiCH5Stb0i1gSbAWjT0sa298fKV6I6b9eB NKE+kCmw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mqD8B-007HSS-7c; Thu, 25 Nov 2021 11:41:35 +0000 Received: from mail-lf1-x12d.google.com ([2a00:1450:4864:20::12d]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mqD87-007HRg-Qg for linux-arm-kernel@lists.infradead.org; Thu, 25 Nov 2021 11:41:33 +0000 Received: by mail-lf1-x12d.google.com with SMTP id c32so15649710lfv.4 for ; Thu, 25 Nov 2021 03:41:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding:content-language; bh=c+s/ogUtJiq8S6eCkJtlg22v9K/HbWbi58ZiTPq2lfQ=; b=fEsKucNIoXRU8fo1RSw4S8M/6nduiyxDjhqJA4RiKZ+9nzT/MbK9afRfBn5g5SUR18 iglOJ+IYQZcHBXgOfPgSM2Ue3RD9HGykxe7VGf/+Bw/5irbG8S3T0RiiZs1QvQiDgX8D IhT6G73L4XYoVnu1AvVvCvbFtXgOT0gZnOPImOJF6q4jEXt8IqMunTAcrJ5Yvk2XLyUt kAnJkjO1id1VHd8fkz4VwIdRw5FNGPfOWVApGLzWSDB1CJYRJzz5bsxA0EiQK3Lwc54P NHNyuVTP68C85JrREwxySo6awlAUd/uTo3L+vt2dcuWhGniSh/jgGevZW2tAxqMKI12A xb9A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=c+s/ogUtJiq8S6eCkJtlg22v9K/HbWbi58ZiTPq2lfQ=; b=m/Uzd3hLwfpyrdgE9NDLnik+icaMcYQ5rtGtk2R350bxr9QPkaKj1fGvs6eVrtbHt9 14Go5J+vOzP7bf7wGWav31ClI49sKytrzfbzHZ/DGcOTaxImHFjbvR5LawnScyWcyQOq B7A5p17hWfU0B/LkpNjj3td4HVdgg+6zdB0iHid8IuCfBu8Ov1m8DyNf455NpK2DJFv1 dgQeiVp2V0FAU9aXWbHRL0SSOaiCJ+DqmVSUIMJjKdIyl3MpIz6slf+/89Tl61REiKY2 kEtVqKSkQh7b2zmk6SdRpW1zF4a7nK1D1AfEutxwqYckwNr47yrzpS1IU9NVGFH/LLAV z+5g== X-Gm-Message-State: AOAM531wRcRxb1NRTM/6uzdQn82v2Ieu38nczucaDCNGEkMxjJwmeuPR ZNDtE3tvIr4uUxR8g/V3tSg= X-Google-Smtp-Source: ABdhPJwMfQ7CxY+YVrpFAi0AiKCeie5qzWnKWf11oidpWyS5Ss9HlABYbHfrCBdhkQNwbB3mJec7pw== X-Received: by 2002:a05:6512:10c5:: with SMTP id k5mr15043810lfg.367.1637840488404; Thu, 25 Nov 2021 03:41:28 -0800 (PST) Received: from [192.168.1.7] ([212.22.223.21]) by smtp.gmail.com with ESMTPSA id n15sm213163ljm.32.2021.11.25.03.41.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 25 Nov 2021 03:41:28 -0800 (PST) Subject: Re: [PATCH V3 2/6] arm/xen: Switch to use gnttab_setup_auto_xlat_frames() for DT To: Stefano Stabellini Cc: xen-devel@lists.xenproject.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Oleksandr Tyshchenko , Russell King , Julien Grall References: <1637787223-21129-1-git-send-email-olekstysh@gmail.com> <1637787223-21129-3-git-send-email-olekstysh@gmail.com> From: Oleksandr Message-ID: Date: Thu, 25 Nov 2021 13:41:27 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211125_034131_928100_12858110 X-CRM114-Status: GOOD ( 27.29 ) 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: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 25.11.21 01:35, Stefano Stabellini wrote: Hi Stefano > On Wed, 24 Nov 2021, Oleksandr Tyshchenko wrote: >> From: Oleksandr Tyshchenko >> >> Read the start address of the grant table space from DT >> (region 0). >> >> This patch mostly restores behaviour before commit 3cf4095d7446 >> ("arm/xen: Use xen_xlate_map_ballooned_pages to setup grant table") >> but trying not to break the ACPI support added after that commit. >> So the patch touches DT part only and leaves the ACPI part with >> xen_xlate_map_ballooned_pages(). Also in order to make a code more >> resilient use a fallback to xen_xlate_map_ballooned_pages() if grant >> table region wasn't found. >> >> This is a preparation for using Xen extended region feature >> where unused regions of guest physical address space (provided >> by the hypervisor) will be used to create grant/foreign/whatever >> mappings instead of wasting real RAM pages from the domain memory >> for establishing these mappings. >> >> The immediate benefit of this change: >> - Avoid superpage shattering in Xen P2M when establishing >> stage-2 mapping (GFN <-> MFN) for the grant table space >> - Avoid wasting real RAM pages (reducing the amount of memory >> usuable) for mapping grant table space >> - The grant table space is always mapped at the exact >> same place (region 0 is reserved for the grant table) >> >> Signed-off-by: Oleksandr Tyshchenko >> --- >> Changes RFC -> V2: >> - new patch >> >> Changes V2 -> V3: >> - add __read_mostly specifier to xen_grant_frames >> - retain a fallback to xen_xlate_map_ballooned_pages() if >> xen_grant_frames is invalid >> - process xen_events_irq before xen_grant_frames in >> xen_dt_guest_init() >> - update patch description >> --- >> arch/arm/xen/enlighten.c | 26 ++++++++++++++++++++------ >> 1 file changed, 20 insertions(+), 6 deletions(-) >> >> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c >> index 7619fbf..3fb3384 100644 >> --- a/arch/arm/xen/enlighten.c >> +++ b/arch/arm/xen/enlighten.c >> @@ -59,6 +59,9 @@ unsigned long xen_released_pages; >> struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata; >> >> static __read_mostly unsigned int xen_events_irq; >> +static __read_mostly phys_addr_t xen_grant_frames; >> + >> +#define GRANT_TABLE_INDEX 0 >> >> uint32_t xen_start_flags; >> EXPORT_SYMBOL(xen_start_flags); >> @@ -303,6 +306,7 @@ static void __init xen_acpi_guest_init(void) >> static void __init xen_dt_guest_init(void) >> { >> struct device_node *xen_node; >> + struct resource res; >> >> xen_node = of_find_compatible_node(NULL, NULL, "xen,xen"); >> if (!xen_node) { >> @@ -311,13 +315,19 @@ static void __init xen_dt_guest_init(void) >> } >> >> xen_events_irq = irq_of_parse_and_map(xen_node, 0); >> + >> + if (of_address_to_resource(xen_node, GRANT_TABLE_INDEX, &res)) { >> + pr_err("Xen grant table region is not found\n"); >> + return; >> + } >> + xen_grant_frames = res.start; >> } >> >> static int __init xen_guest_init(void) >> { >> struct xen_add_to_physmap xatp; >> struct shared_info *shared_info_page = NULL; >> - int cpu; >> + int rc, cpu; >> >> if (!xen_domain()) >> return 0; >> @@ -370,12 +380,16 @@ static int __init xen_guest_init(void) >> for_each_possible_cpu(cpu) >> per_cpu(xen_vcpu_id, cpu) = cpu; >> >> - xen_auto_xlat_grant_frames.count = gnttab_max_grant_frames(); >> - if (xen_xlate_map_ballooned_pages(&xen_auto_xlat_grant_frames.pfn, >> - &xen_auto_xlat_grant_frames.vaddr, >> - xen_auto_xlat_grant_frames.count)) { >> + if (!acpi_disabled || !xen_grant_frames) { > I realize now that we only need: > > if (!xen_grant_frames) { Indeed, the first part of the check looks superfluous, will do. > > with that: > > Reviewed-by: Stefano Stabellini Thanks! > > > >> + xen_auto_xlat_grant_frames.count = gnttab_max_grant_frames(); >> + rc = xen_xlate_map_ballooned_pages(&xen_auto_xlat_grant_frames.pfn, >> + &xen_auto_xlat_grant_frames.vaddr, >> + xen_auto_xlat_grant_frames.count); >> + } else >> + rc = gnttab_setup_auto_xlat_frames(xen_grant_frames); >> + if (rc) { >> free_percpu(xen_vcpu_info); >> - return -ENOMEM; >> + return rc; >> } >> gnttab_init(); -- Regards, Oleksandr Tyshchenko _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel