From patchwork Wed Nov 24 20:53:42 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleksandr Tyshchenko X-Patchwork-Id: 12693587 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 2E7F2C433F5 for ; Wed, 24 Nov 2021 20:55:40 +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-Transfer-Encoding:Content-Type:MIME-Version:List-Subscribe:List-Help: List-Post:List-Archive:List-Unsubscribe:List-Id:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=3AU/LeX9Q/m8ecHLFThoCHudvZaIXzxnBYkCzwX6N9w=; b=2WB27b94IJCOxp MK9iJwdapR8AyLdTrnKXN51kDY2TojuQxxTPvdkqDCozU9VL/wnwY44CIf/OjLvD6Y97vCD40KZfp 41Js2ZWcz8vltzmwk4icoT0fBXIWXrTOaXgZDWcL6dnwGo2oL+rcKE0DnXgavyM8W7IY0vmKhVqwG Rdg24K3JJACP1ukx1//54/TPoB+O8in6CzDhS9mIbsyIYoMxg2udiciQQJNbBW0ssQ6ll0zi2ExUK HM3NS5dT6bqO4hYPcXCKoRNSVYPiTTJFZtbvUANE9nHgPQa5Yj+iTltdEMPvDjbz/GhSWRY3mJacw walcANbq7Dx4lEQ5ZHTg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mpzHa-005pAO-JS; Wed, 24 Nov 2021 20:54:22 +0000 Received: from mail-lf1-x133.google.com ([2a00:1450:4864:20::133]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mpzHD-005p56-8q for linux-arm-kernel@lists.infradead.org; Wed, 24 Nov 2021 20:54:00 +0000 Received: by mail-lf1-x133.google.com with SMTP id b40so10505630lfv.10 for ; Wed, 24 Nov 2021 12:53:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=6BK2WZwb7zq+nPDby6saZ0ECEZqzY7Q9bsnh/xJVDtQ=; b=DkhUoPEN5m+YhS0lj/KCPaF95+pgtJLV5AHPKag6SzOXvNY8l/RXclREtUmZBRXscQ w5L+m8mw81fWWD6/E4znSDcSPnrJzgzHKoUFBsWENKP80jotPoLGwbYn3R5HifysInuH Uivjr6j/0kWaIam3Hs3m3s2HMrn2zjLLGFrIEbkq3A7k71iyLEBAspL/4RH9/Lq6907o LEQBmA6woloWkcHZ/v7JD/WbkdPUzyNd+wxQIV09bGMkL6ruQjYv9JYLVHD793Sf4syE f1SmLonhVWMSayC5fvRhjuy+cDukmAAXmCFj+yvwpbZI7hO2YJDJJ/g9zI+SXXsdRtu1 ht+A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=6BK2WZwb7zq+nPDby6saZ0ECEZqzY7Q9bsnh/xJVDtQ=; b=bVax0sdXvNDIlyIfPuhW1DgXVAMkD8NJZDiz461hwG+4X9+vpFrvRrcId7KqhTol2F uJdLYAGvO3C45S3KRT2Xu4orwz1mPpyEx3ltvXymFu6HCSVl3CIHk41tkCMw8/iB1sLB 4UqX5MFypgHqtRrRw6sLfLFEtv+qE1Qz0VqAIPDOiQpcG4ZGbzCZPK4lo6nP4wqWbdgm msyt62DAf5a4DuqGP1mQspjrSqu2LysTAmVJlkuo/o435ICywhSlKTw3bnonDxD8X9Xf QGhU1fQrv4I2ablBH70Ri6Hjcvbg7X89TYkspCTeC0fSkQjkPsbaLFN8XAiNvBkf8Af8 9usQ== X-Gm-Message-State: AOAM531n/I7D8uk6zG1z9emNAkFsajh1bMpKbgg3DFhoFmiVBU3dXolW JA9FREwKzH+pfnqnlc0SFOY= X-Google-Smtp-Source: ABdhPJxBc8gDofCcpBfj+VeGAsm146fKsnDAoZr0N7d3GVfA5RjaGuaXAWpczZc9US5dPuW598oREg== X-Received: by 2002:a05:6512:3763:: with SMTP id z3mr18059562lft.315.1637787237574; Wed, 24 Nov 2021 12:53:57 -0800 (PST) Received: from otyshchenko.router ([212.22.223.21]) by smtp.gmail.com with ESMTPSA id j11sm97608ljc.9.2021.11.24.12.53.56 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 Nov 2021 12:53:57 -0800 (PST) From: Oleksandr Tyshchenko To: xen-devel@lists.xenproject.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Oleksandr Tyshchenko , Boris Ostrovsky , Juergen Gross , Stefano Stabellini , Russell King , Julien Grall Subject: [PATCH V3 5/6] arm/xen: Read extended regions from DT and init Xen resource Date: Wed, 24 Nov 2021 22:53:42 +0200 Message-Id: <1637787223-21129-6-git-send-email-olekstysh@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1637787223-21129-1-git-send-email-olekstysh@gmail.com> References: <1637787223-21129-1-git-send-email-olekstysh@gmail.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211124_125359_349945_C0AA830E X-CRM114-Status: GOOD ( 26.05 ) 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: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Oleksandr Tyshchenko This patch implements arch_xen_unpopulated_init() on Arm where the extended regions (if any) are gathered from DT and inserted into specific Xen resource to be used as unused address space for Xen scratch pages by unpopulated-alloc code. The extended region (safe range) is a region of guest physical address space which is unused and could be safely used to create grant/foreign mappings instead of wasting real RAM pages from the domain memory for establishing these mappings. The extended regions are chosen by the hypervisor at the domain creation time and advertised to it via "reg" property under hypervisor node in the guest device-tree. As region 0 is reserved for grant table space (always present), the indexes for extended regions are 1...N. If arch_xen_unpopulated_init() fails for some reason the default behaviour will be restored (allocate xenballooned pages). This patch also removes XEN_UNPOPULATED_ALLOC dependency on x86. Signed-off-by: Oleksandr Tyshchenko Reviewed-by: Stefano Stabellini --- Changes RFC -> V2: - new patch, instead of "[RFC PATCH 2/2] xen/unpopulated-alloc: Query hypervisor to provide unallocated space" Changes V2 -> V3: - update comments in code - drop the checks that a region is within the hotpluggable range, now the common code takes care of - update arch_xen_unpopulated_init() according to interface change, move xen_resource here, etc - use %pR specifier in error message - bait out in arch_xen_unpopulated_init() if !acpi_disabled - update checks in second loop in arch_xen_unpopulated_init() for the sake of clarity --- arch/arm/xen/enlighten.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++ drivers/xen/Kconfig | 2 +- 2 files changed, 107 insertions(+), 1 deletion(-) diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c index 3fb3384..019caa6 100644 --- a/arch/arm/xen/enlighten.c +++ b/arch/arm/xen/enlighten.c @@ -62,6 +62,7 @@ static __read_mostly unsigned int xen_events_irq; static __read_mostly phys_addr_t xen_grant_frames; #define GRANT_TABLE_INDEX 0 +#define EXT_REGION_INDEX 1 uint32_t xen_start_flags; EXPORT_SYMBOL(xen_start_flags); @@ -303,6 +304,111 @@ static void __init xen_acpi_guest_init(void) #endif } +#ifdef CONFIG_XEN_UNPOPULATED_ALLOC +/* + * A type-less specific Xen resource which contains extended regions + * (unused regions of guest physical address space provided by the hypervisor). + */ +static struct resource xen_resource = { + .name = "Xen unused space", +}; + +int __init arch_xen_unpopulated_init(struct resource **res) +{ + struct device_node *np; + struct resource *regs, *tmp_res; + uint64_t min_gpaddr = -1, max_gpaddr = 0; + unsigned int i, nr_reg = 0; + int rc; + + if (!xen_domain()) + return -ENODEV; + + if (!acpi_disabled) + return -ENODEV; + + np = of_find_compatible_node(NULL, NULL, "xen,xen"); + if (WARN_ON(!np)) + return -ENODEV; + + /* Skip region 0 which is reserved for grant table space */ + while (of_get_address(np, nr_reg + EXT_REGION_INDEX, NULL, NULL)) + nr_reg++; + + if (!nr_reg) { + pr_err("No extended regions are found\n"); + return -EINVAL; + } + + regs = kcalloc(nr_reg, sizeof(*regs), GFP_KERNEL); + if (!regs) + return -ENOMEM; + + /* + * Create resource from extended regions provided by the hypervisor to be + * used as unused address space for Xen scratch pages. + */ + for (i = 0; i < nr_reg; i++) { + rc = of_address_to_resource(np, i + EXT_REGION_INDEX, ®s[i]); + if (rc) + goto err; + + if (max_gpaddr < regs[i].end) + max_gpaddr = regs[i].end; + if (min_gpaddr > regs[i].start) + min_gpaddr = regs[i].start; + } + + xen_resource.start = min_gpaddr; + xen_resource.end = max_gpaddr; + + /* + * Mark holes between extended regions as unavailable. The rest of that + * address space will be available for the allocation. + */ + for (i = 1; i < nr_reg; i++) { + resource_size_t start, end; + + /* There is an overlap between regions */ + if (regs[i - 1].end + 1 > regs[i].start) { + rc = -EINVAL; + goto err; + } + + /* There is no hole between regions */ + if (regs[i - 1].end + 1 == regs[i].start) + continue; + + start = regs[i - 1].end + 1; + end = regs[i].start - 1; + + tmp_res = kzalloc(sizeof(*tmp_res), GFP_KERNEL); + if (!tmp_res) { + rc = -ENOMEM; + goto err; + } + + tmp_res->name = "Unavailable space"; + tmp_res->start = start; + tmp_res->end = end; + + rc = insert_resource(&xen_resource, tmp_res); + if (rc) { + pr_err("Cannot insert resource %pR (%d)\n", tmp_res, rc); + kfree(tmp_res); + goto err; + } + } + + *res = &xen_resource; + +err: + kfree(regs); + + return rc; +} +#endif + static void __init xen_dt_guest_init(void) { struct device_node *xen_node; diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig index a1b11c62..553b614 100644 --- a/drivers/xen/Kconfig +++ b/drivers/xen/Kconfig @@ -321,7 +321,7 @@ config XEN_FRONT_PGDIR_SHBUF config XEN_UNPOPULATED_ALLOC bool "Use unpopulated memory ranges for guest mappings" - depends on X86 && ZONE_DEVICE + depends on ZONE_DEVICE default XEN_BACKEND || XEN_GNTDEV || XEN_DOM0 help Use unpopulated memory ranges in order to create mappings for guest