From patchwork Mon Jan 25 18:39:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 372481 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, 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 EAF81C433DB for ; Tue, 26 Jan 2021 04:48:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A9F3122B2C for ; Tue, 26 Jan 2021 04:48:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727851AbhAZErt (ORCPT ); Mon, 25 Jan 2021 23:47:49 -0500 Received: from mail.kernel.org ([198.145.29.99]:58346 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727878AbhAYSoc (ORCPT ); Mon, 25 Jan 2021 13:44:32 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id D217D206FA; Mon, 25 Jan 2021 18:44:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1611600252; bh=agTNM9rvcnuopW4ImTad5Lj786zO/UCc6mvDQtFFCos=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gP2asAI78YCsBcmQKUR28Ry3IY0KE3EIPKLDxMSFSURYpP0XaKhA/CK/sWJzdQ0/3 QRt2ImuB9PyM3l3f4c1QcFCQTrGj+FQbMjpS6ihJok+XiNRpyRQ7CKarAbxNCI1doY L0yRcszwQiRLueQ58Fqf9MfQN1vO7dAw2U6xTFwM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Woodhouse , Boris Ostrovsky , Juergen Gross , Sasha Levin Subject: [PATCH 5.4 30/86] xen: Fix event channel callback via INTX/GSI Date: Mon, 25 Jan 2021 19:39:12 +0100 Message-Id: <20210125183202.331926864@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210125183201.024962206@linuxfoundation.org> References: <20210125183201.024962206@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: David Woodhouse [ Upstream commit 3499ba8198cad47b731792e5e56b9ec2a78a83a2 ] For a while, event channel notification via the PCI platform device has been broken, because we attempt to communicate with xenstore before we even have notifications working, with the xs_reset_watches() call in xs_init(). We tend to get away with this on Xen versions below 4.0 because we avoid calling xs_reset_watches() anyway, because xenstore might not cope with reading a non-existent key. And newer Xen *does* have the vector callback support, so we rarely fall back to INTX/GSI delivery. To fix it, clean up a bit of the mess of xs_init() and xenbus_probe() startup. Call xs_init() directly from xenbus_init() only in the !XS_HVM case, deferring it to be called from xenbus_probe() in the XS_HVM case instead. Then fix up the invocation of xenbus_probe() to happen either from its device_initcall if the callback is available early enough, or when the callback is finally set up. This means that the hack of calling xenbus_probe() from a workqueue after the first interrupt, or directly from the PCI platform device setup, is no longer needed. Signed-off-by: David Woodhouse Reviewed-by: Boris Ostrovsky Link: https://lore.kernel.org/r/20210113132606.422794-2-dwmw2@infradead.org Signed-off-by: Juergen Gross Signed-off-by: Sasha Levin --- arch/arm/xen/enlighten.c | 2 +- drivers/xen/events/events_base.c | 10 ---- drivers/xen/platform-pci.c | 1 - drivers/xen/xenbus/xenbus.h | 1 + drivers/xen/xenbus/xenbus_comms.c | 8 --- drivers/xen/xenbus/xenbus_probe.c | 81 +++++++++++++++++++++++++------ include/xen/xenbus.h | 2 +- 7 files changed, 70 insertions(+), 35 deletions(-) diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c index dd6804a64f1a0..f45bff158fc20 100644 --- a/arch/arm/xen/enlighten.c +++ b/arch/arm/xen/enlighten.c @@ -371,7 +371,7 @@ static int __init xen_guest_init(void) } gnttab_init(); if (!xen_initial_domain()) - xenbus_probe(NULL); + xenbus_probe(); /* * Making sure board specific code will not set up ops for diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c index 26df84c45db4e..7b94a6c316643 100644 --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -1988,16 +1988,6 @@ static struct irq_chip xen_percpu_chip __read_mostly = { .irq_ack = ack_dynirq, }; -int xen_set_callback_via(uint64_t via) -{ - struct xen_hvm_param a; - a.domid = DOMID_SELF; - a.index = HVM_PARAM_CALLBACK_IRQ; - a.value = via; - return HYPERVISOR_hvm_op(HVMOP_set_param, &a); -} -EXPORT_SYMBOL_GPL(xen_set_callback_via); - #ifdef CONFIG_XEN_PVHVM /* Vector callbacks are better than PCI interrupts to receive event * channel notifications because we can receive vector callbacks on any diff --git a/drivers/xen/platform-pci.c b/drivers/xen/platform-pci.c index 5e30602fdbad8..c45646450135f 100644 --- a/drivers/xen/platform-pci.c +++ b/drivers/xen/platform-pci.c @@ -149,7 +149,6 @@ static int platform_pci_probe(struct pci_dev *pdev, ret = gnttab_init(); if (ret) goto grant_out; - xenbus_probe(NULL); return 0; grant_out: gnttab_free_auto_xlat_frames(); diff --git a/drivers/xen/xenbus/xenbus.h b/drivers/xen/xenbus/xenbus.h index 88516a8a9f932..a9bb5f91082d3 100644 --- a/drivers/xen/xenbus/xenbus.h +++ b/drivers/xen/xenbus/xenbus.h @@ -115,6 +115,7 @@ int xenbus_probe_node(struct xen_bus_type *bus, const char *type, const char *nodename); int xenbus_probe_devices(struct xen_bus_type *bus); +void xenbus_probe(void); void xenbus_dev_changed(const char *node, struct xen_bus_type *bus); diff --git a/drivers/xen/xenbus/xenbus_comms.c b/drivers/xen/xenbus/xenbus_comms.c index eb5151fc8efab..e5fda0256feb3 100644 --- a/drivers/xen/xenbus/xenbus_comms.c +++ b/drivers/xen/xenbus/xenbus_comms.c @@ -57,16 +57,8 @@ DEFINE_MUTEX(xs_response_mutex); static int xenbus_irq; static struct task_struct *xenbus_task; -static DECLARE_WORK(probe_work, xenbus_probe); - - static irqreturn_t wake_waiting(int irq, void *unused) { - if (unlikely(xenstored_ready == 0)) { - xenstored_ready = 1; - schedule_work(&probe_work); - } - wake_up(&xb_waitq); return IRQ_HANDLED; } diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c index e6d0903459e11..14ccf13ab8fa1 100644 --- a/drivers/xen/xenbus/xenbus_probe.c +++ b/drivers/xen/xenbus/xenbus_probe.c @@ -683,29 +683,76 @@ void unregister_xenstore_notifier(struct notifier_block *nb) } EXPORT_SYMBOL_GPL(unregister_xenstore_notifier); -void xenbus_probe(struct work_struct *unused) +void xenbus_probe(void) { xenstored_ready = 1; + /* + * In the HVM case, xenbus_init() deferred its call to + * xs_init() in case callbacks were not operational yet. + * So do it now. + */ + if (xen_store_domain_type == XS_HVM) + xs_init(); + /* Notify others that xenstore is up */ blocking_notifier_call_chain(&xenstore_chain, 0, NULL); } -EXPORT_SYMBOL_GPL(xenbus_probe); -static int __init xenbus_probe_initcall(void) +/* + * Returns true when XenStore init must be deferred in order to + * allow the PCI platform device to be initialised, before we + * can actually have event channel interrupts working. + */ +static bool xs_hvm_defer_init_for_callback(void) { - if (!xen_domain()) - return -ENODEV; +#ifdef CONFIG_XEN_PVHVM + return xen_store_domain_type == XS_HVM && + !xen_have_vector_callback; +#else + return false; +#endif +} - if (xen_initial_domain() || xen_hvm_domain()) - return 0; +static int __init xenbus_probe_initcall(void) +{ + /* + * Probe XenBus here in the XS_PV case, and also XS_HVM unless we + * need to wait for the platform PCI device to come up. + */ + if (xen_store_domain_type == XS_PV || + (xen_store_domain_type == XS_HVM && + !xs_hvm_defer_init_for_callback())) + xenbus_probe(); - xenbus_probe(NULL); return 0; } - device_initcall(xenbus_probe_initcall); +int xen_set_callback_via(uint64_t via) +{ + struct xen_hvm_param a; + int ret; + + a.domid = DOMID_SELF; + a.index = HVM_PARAM_CALLBACK_IRQ; + a.value = via; + + ret = HYPERVISOR_hvm_op(HVMOP_set_param, &a); + if (ret) + return ret; + + /* + * If xenbus_probe_initcall() deferred the xenbus_probe() + * due to the callback not functioning yet, we can do it now. + */ + if (!xenstored_ready && xs_hvm_defer_init_for_callback()) + xenbus_probe(); + + return ret; +} +EXPORT_SYMBOL_GPL(xen_set_callback_via); + /* Set up event channel for xenstored which is run as a local process * (this is normally used only in dom0) */ @@ -818,11 +865,17 @@ static int __init xenbus_init(void) break; } - /* Initialize the interface to xenstore. */ - err = xs_init(); - if (err) { - pr_warn("Error initializing xenstore comms: %i\n", err); - goto out_error; + /* + * HVM domains may not have a functional callback yet. In that + * case let xs_init() be called from xenbus_probe(), which will + * get invoked at an appropriate time. + */ + if (xen_store_domain_type != XS_HVM) { + err = xs_init(); + if (err) { + pr_warn("Error initializing xenstore comms: %i\n", err); + goto out_error; + } } if ((xen_store_domain_type != XS_LOCAL) && diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h index eba01ab5a55e0..fe9a9fa2ebc45 100644 --- a/include/xen/xenbus.h +++ b/include/xen/xenbus.h @@ -187,7 +187,7 @@ void xs_suspend_cancel(void); struct work_struct; -void xenbus_probe(struct work_struct *); +void xenbus_probe(void); #define XENBUS_IS_ERR_READ(str) ({ \ if (!IS_ERR(str) && strlen(str) == 0) { \