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 X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1E78DC433DB for ; Mon, 25 Jan 2021 19:21:18 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id B5FAA2256F for ; Mon, 25 Jan 2021 19:21:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B5FAA2256F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.74381.133745 (Exim 4.92) (envelope-from ) id 1l47QD-0003fu-0X; Mon, 25 Jan 2021 19:21:09 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 74381.133745; Mon, 25 Jan 2021 19:21:08 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l47QC-0003fU-LX; Mon, 25 Jan 2021 19:21:08 +0000 Received: by outflank-mailman (input) for mailman id 74381; Mon, 25 Jan 2021 19:21:07 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l47GJ-0008N7-JR for xen-devel@lists.xenproject.org; Mon, 25 Jan 2021 19:10:55 +0000 Received: from mail-wm1-x333.google.com (unknown [2a00:1450:4864:20::333]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 5bc4c605-df07-442b-8357-7150c8be4ed9; Mon, 25 Jan 2021 19:09:19 +0000 (UTC) Received: by mail-wm1-x333.google.com with SMTP id m187so388585wme.2 for ; Mon, 25 Jan 2021 11:09:16 -0800 (PST) Received: from otyshchenko.www.tendawifi.com ([212.22.223.21]) by smtp.gmail.com with ESMTPSA id k6sm12991031wro.27.2021.01.25.11.09.15 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 25 Jan 2021 11:09:15 -0800 (PST) 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: 5bc4c605-df07-442b-8357-7150c8be4ed9 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=56q3vS7kTPjkBeZpCedlA35sj1F6SAbFf73YA28cuDw=; b=NAQXLR3YC0ePDFcJsMH2mJiS9iq1e7hqncXyhKPgAIZMXHKYL90qKiw9NPln14JyhJ ko/xbh3dydPY5irT9V1He2YZE32F2nM/EXck5OgfqpTzh9mC+T43vXlsCduaHjZM+u8/ CMyvM8Vsx81GVsTyVd1aQeaYP9LO7AekDaITxS+WU/0KejucOPTaVBZlwGLMw2dG8oQY ACi9SUyne7kX/xeLPKxVZ6my/XbN0GiGE1c9eA6iYAOBRSd+gXd/cnmqexzyejRGTeYG Imara8PFomv2OPOgIUkvSHWHkOUSc4zIxe926xQqwcDHpS2RyOHOeTEkSE6D/6ncvsd2 00AQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=56q3vS7kTPjkBeZpCedlA35sj1F6SAbFf73YA28cuDw=; b=teMn0cPjRhsuaOc0sTZQXvngmm8sK4YvDwvCt00FViUcC6D8WVxYDGhoGOH77WrekW CFYGCIP+IiBOPBpssnT7eBOlYGOWVhyjdT+BIn9NPEaDiqZgwNuelKzS1ezaSAbQq951 8f7z0V4IffMGznwXgg1cGYlCkZCfUVm0IY6QbP3eOTBQdHPpqKfot93xP3r/RjYpU7ZD DAZe/ISlJGG1desqYtf2OLHEQfBi5935JwrjOcX8XFS/6dORFGZ2rnwE6xR716kFdDXE LSRWC2FgZx4R8DjhaUhwf7MQx/W/OqvKXhp83rmgkhQw2CUaB88J4Yru7xpkQMmBDJx9 /Jqw== X-Gm-Message-State: AOAM530l4gmylGvep/xpp00r7krgexN+w1CNpJFkGPXCStpuFZuInwoh Wj9QKVTLAkeSBCusKq6f1p4WZxwQjninRA== X-Google-Smtp-Source: ABdhPJxqWxZA1UNJHCs8azX6BOxbaVbtxb6CX9NTt1ZK8DMoPsOuUD+DEbXrlAAjS6M6ec1aRQWp0Q== X-Received: by 2002:a1c:a593:: with SMTP id o141mr1467438wme.92.1611601755965; Mon, 25 Jan 2021 11:09:15 -0800 (PST) From: Oleksandr Tyshchenko To: xen-devel@lists.xenproject.org Cc: Oleksandr Tyshchenko , Stefano Stabellini , Julien Grall , Volodymyr Babchuk , Julien Grall Subject: [PATCH V5 22/22] xen/arm: Add mapcache invalidation handling Date: Mon, 25 Jan 2021 21:08:29 +0200 Message-Id: <1611601709-28361-23-git-send-email-olekstysh@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1611601709-28361-1-git-send-email-olekstysh@gmail.com> References: <1611601709-28361-1-git-send-email-olekstysh@gmail.com> From: Oleksandr Tyshchenko We need to send mapcache invalidation request to qemu/demu everytime the page gets removed from a guest. At the moment, the Arm code doesn't explicitely remove the existing mapping before inserting the new mapping. Instead, this is done implicitely by __p2m_set_entry(). So we need to recognize a case when old entry is a RAM page *and* the new MFN is different in order to set the corresponding flag. The most suitable place to do this is p2m_free_entry(), there we can find the correct leaf type. The invalidation request will be sent in do_trap_hypercall() later on. Taking into the account the following the do_trap_hypercall() is the best place to send invalidation request: - The only way a guest can modify its P2M on Arm is via an hypercall - When sending the invalidation request, the vCPU will be blocked until all the IOREQ servers have acknowledged the invalidation Signed-off-by: Oleksandr Tyshchenko CC: Julien Grall Reviewed-by: Stefano Stabellini [On Arm only] Tested-by: Wei Chen --- Please note, this is a split/cleanup/hardening of Julien's PoC: "Add support for Guest IO forwarding to a device emulator" *** Please note, this patch depends on the following which is on review: https://patchwork.kernel.org/patch/11803383/ This patch is on par with x86 code (whether it is buggy or not). If there is a need to improve/harden something, this can be done on a follow-up. *** Changes V1 -> V2: - new patch, some changes were derived from (+ new explanation): xen/ioreq: Make x86's invalidate qemu mapcache handling common - put setting of the flag into __p2m_set_entry() - clarify the conditions when the flag should be set - use domain_has_ioreq_server() - update do_trap_hypercall() by adding local variable Changes V2 -> V3: - update patch description - move check to p2m_free_entry() - add a comment - use "curr" instead of "v" in do_trap_hypercall() Changes V3 -> V4: - update patch description - re-order check in p2m_free_entry() to call domain_has_ioreq_server() only if p2m->domain == current->domain - add a comment in do_trap_hypercall() Changes V4 -> V5: - add Stefano's R-b - update comment in do_trap_hypercall() --- --- xen/arch/arm/p2m.c | 25 +++++++++++++++++-------- xen/arch/arm/traps.c | 20 +++++++++++++++++--- 2 files changed, 34 insertions(+), 11 deletions(-) diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c index d41c4fa..26acb95d 100644 --- a/xen/arch/arm/p2m.c +++ b/xen/arch/arm/p2m.c @@ -1,6 +1,7 @@ #include #include #include +#include #include #include #include @@ -749,17 +750,25 @@ static void p2m_free_entry(struct p2m_domain *p2m, if ( !p2m_is_valid(entry) ) return; - /* Nothing to do but updating the stats if the entry is a super-page. */ - if ( p2m_is_superpage(entry, level) ) + if ( p2m_is_superpage(entry, level) || (level == 3) ) { - p2m->stats.mappings[level]--; - return; - } +#ifdef CONFIG_IOREQ_SERVER + /* + * If this gets called (non-recursively) then either the entry + * was replaced by an entry with a different base (valid case) or + * the shattering of a superpage was failed (error case). + * So, at worst, the spurious mapcache invalidation might be sent. + */ + if ( (p2m->domain == current->domain) && + domain_has_ioreq_server(p2m->domain) && + p2m_is_ram(entry.p2m.type) ) + p2m->domain->mapcache_invalidate = true; +#endif - if ( level == 3 ) - { p2m->stats.mappings[level]--; - p2m_put_l3_page(entry); + /* Nothing to do if the entry is a super-page. */ + if ( level == 3 ) + p2m_put_l3_page(entry); return; } diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c index 4cdd343..64b740b 100644 --- a/xen/arch/arm/traps.c +++ b/xen/arch/arm/traps.c @@ -1443,6 +1443,7 @@ static void do_trap_hypercall(struct cpu_user_regs *regs, register_t *nr, const union hsr hsr) { arm_hypercall_fn_t call = NULL; + struct vcpu *curr = current; BUILD_BUG_ON(NR_hypercalls < ARRAY_SIZE(arm_hypercall_table) ); @@ -1459,7 +1460,7 @@ static void do_trap_hypercall(struct cpu_user_regs *regs, register_t *nr, return; } - current->hcall_preempted = false; + curr->hcall_preempted = false; perfc_incra(hypercalls, *nr); call = arm_hypercall_table[*nr].fn; @@ -1472,7 +1473,7 @@ static void do_trap_hypercall(struct cpu_user_regs *regs, register_t *nr, HYPERCALL_RESULT_REG(regs) = call(HYPERCALL_ARGS(regs)); #ifndef NDEBUG - if ( !current->hcall_preempted ) + if ( !curr->hcall_preempted ) { /* Deliberately corrupt parameter regs used by this hypercall. */ switch ( arm_hypercall_table[*nr].nr_args ) { @@ -1489,8 +1490,21 @@ static void do_trap_hypercall(struct cpu_user_regs *regs, register_t *nr, #endif /* Ensure the hypercall trap instruction is re-executed. */ - if ( current->hcall_preempted ) + if ( curr->hcall_preempted ) regs->pc -= 4; /* re-execute 'hvc #XEN_HYPERCALL_TAG' */ + +#ifdef CONFIG_IOREQ_SERVER + /* + * We call ioreq_signal_mapcache_invalidate from do_trap_hypercall() + * because the only way a guest can modify its P2M on Arm is via an + * hypercall. + * Note that sending the invalidation request causes the vCPU to block + * until all the IOREQ servers have acknowledged the invalidation. + */ + if ( unlikely(curr->domain->mapcache_invalidate) && + test_and_clear_bool(curr->domain->mapcache_invalidate) ) + ioreq_signal_mapcache_invalidate(); +#endif } void arch_hypercall_tasklet_result(struct vcpu *v, long res) -- 2.7.4