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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 0BE69C433F5 for ; Wed, 24 Nov 2021 23:36:27 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.230593.398639 (Exim 4.92) (envelope-from ) id 1mq1nz-0000Tk-PF; Wed, 24 Nov 2021 23:35:59 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 230593.398639; Wed, 24 Nov 2021 23:35:59 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mq1nz-0000Td-Lr; Wed, 24 Nov 2021 23:35:59 +0000 Received: by outflank-mailman (input) for mailman id 230593; Wed, 24 Nov 2021 23:35:58 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mq1ny-0000TW-JQ for xen-devel@lists.xenproject.org; Wed, 24 Nov 2021 23:35:58 +0000 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 4334c3f3-4d7f-11ec-a9d2-d9f7a1cc8784; Thu, 25 Nov 2021 00:35:56 +0100 (CET) Received: by mail.kernel.org (Postfix) with ESMTPSA id AE98160F12; Wed, 24 Nov 2021 23:35:51 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 4334c3f3-4d7f-11ec-a9d2-d9f7a1cc8784 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637796952; bh=nPrNItrkZzgIB91C/Xwr4wBRunHOMHdNFSsrBmYafok=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=pv91MMp2Xx+Nhh0KE08I0gNIJ8WemEh04U5gPK2vCVKhQAT6zmyAEGfbrMU2mOE+F xM086wsWEmFcTjPU/iequRzWftoTYVPFPNv6Q9N+5XaKikbjl5TQS+9nD7j+lQhLHr YQjOihNB4c2Ivrd8kjfoQkj+Wg3nayp397fNw8j0wCci3BR0hcAUjVfOX6fVv2pQ2f gAmIcaLpK2Vl6G8C78yqp/VdCK/gUWajeT0/TIyoBNwBDBi6hBTEbEor0xkZVjOmjm rNVNvkOzNwv5Sh6itjd5EL5ugVvl6IC8ZrY371061/YhO5Texk9eo/MetOOqbkDAtb y93ZQFGdXtIaA== Date: Wed, 24 Nov 2021 15:35:50 -0800 (PST) From: Stefano Stabellini X-X-Sender: sstabellini@ubuntu-linux-20-04-desktop To: Oleksandr Tyshchenko cc: xen-devel@lists.xenproject.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Oleksandr Tyshchenko , Stefano Stabellini , Russell King , Julien Grall Subject: Re: [PATCH V3 2/6] arm/xen: Switch to use gnttab_setup_auto_xlat_frames() for DT In-Reply-To: <1637787223-21129-3-git-send-email-olekstysh@gmail.com> Message-ID: References: <1637787223-21129-1-git-send-email-olekstysh@gmail.com> <1637787223-21129-3-git-send-email-olekstysh@gmail.com> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII 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) { with that: Reviewed-by: Stefano Stabellini > + 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();