From patchwork Sat Jan 16 00:01:40 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 8045581 Return-Path: X-Original-To: patchwork-xen-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 5C4A29F744 for ; Sat, 16 Jan 2016 00:10:36 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 59AB520379 for ; Sat, 16 Jan 2016 00:10:35 +0000 (UTC) Received: from lists.xen.org (lists.xenproject.org [50.57.142.19]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 36AF32034C for ; Sat, 16 Jan 2016 00:10:34 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xen.org) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1aKEP7-0001ZD-6D; Sat, 16 Jan 2016 00:07:41 +0000 Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1aKEP5-0001Z8-50 for xen-devel@lists.xenproject.org; Sat, 16 Jan 2016 00:07:39 +0000 Received: from [193.109.254.147] by server-2.bemta-14.messagelabs.com id 85/1C-12889-AC989965; Sat, 16 Jan 2016 00:07:38 +0000 X-Env-Sender: kamal@canonical.com X-Msg-Ref: server-16.tower-27.messagelabs.com!1452902857!17171892!1 X-Originating-IP: [91.189.89.112] X-SpamReason: No, hits=0.5 required=7.0 tests=BODY_RANDOM_LONG X-StarScan-Received: X-StarScan-Version: 7.35.1; banners=-,-,- X-VirusChecked: Checked Received: (qmail 13505 invoked from network); 16 Jan 2016 00:07:37 -0000 Received: from youngberry.canonical.com (HELO youngberry.canonical.com) (91.189.89.112) by server-16.tower-27.messagelabs.com with AES256-SHA encrypted SMTP; 16 Jan 2016 00:07:37 -0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1aKEP2-0008KX-Es; Sat, 16 Jan 2016 00:07:36 +0000 Received: from kamal by fourier with local (Exim 4.82) (envelope-from ) id 1aKEOz-0002KZ-LX; Fri, 15 Jan 2016 16:07:33 -0800 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Date: Fri, 15 Jan 2016 16:01:40 -0800 Message-Id: <1452902519-2754-287-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1452902519-2754-1-git-send-email-kamal@canonical.com> References: <1452902519-2754-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 4.2 Cc: Kamal Mostafa , Thomas Gleixner , David Vrabel , xen-devel@lists.xenproject.org, vkuznets@redhat.com, Boris Ostrovsky Subject: [Xen-devel] [PATCH 4.2.y-ckt 286/305] x86/paravirt: Prevent rtc_cmos platform device init on PV guests X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 4.2.8-ckt2 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: David Vrabel commit d8c98a1d1488747625ad6044d423406e17e99b7a upstream. Adding the rtc platform device in non-privileged Xen PV guests causes an IRQ conflict because these guests do not have legacy PIC and may allocate irqs in the legacy range. In a single VCPU Xen PV guest we should have: /proc/interrupts: CPU0 0: 4934 xen-percpu-virq timer0 1: 0 xen-percpu-ipi spinlock0 2: 0 xen-percpu-ipi resched0 3: 0 xen-percpu-ipi callfunc0 4: 0 xen-percpu-virq debug0 5: 0 xen-percpu-ipi callfuncsingle0 6: 0 xen-percpu-ipi irqwork0 7: 321 xen-dyn-event xenbus 8: 90 xen-dyn-event hvc_console ... But hvc_console cannot get its interrupt because it is already in use by rtc0 and the console does not work. genirq: Flags mismatch irq 8. 00000000 (hvc_console) vs. 00000000 (rtc0) We can avoid this problem by realizing that unprivileged PV guests (both Xen and lguests) are not supposed to have rtc_cmos device and so adding it is not necessary. Privileged guests (i.e. Xen's dom0) do use it but they should not have irq conflicts since they allocate irqs above legacy range (above gsi_top, in fact). Instead of explicitly testing whether the guest is privileged we can extend pv_info structure to include information about guest's RTC support. Reported-and-tested-by: Sander Eikelenboom Signed-off-by: David Vrabel Signed-off-by: Boris Ostrovsky Cc: vkuznets@redhat.com Cc: xen-devel@lists.xenproject.org Cc: konrad.wilk@oracle.com Link: http://lkml.kernel.org/r/1449842873-2613-1-git-send-email-boris.ostrovsky@oracle.com Signed-off-by: Thomas Gleixner Signed-off-by: Kamal Mostafa --- arch/x86/include/asm/paravirt.h | 6 ++++++ arch/x86/include/asm/paravirt_types.h | 5 +++++ arch/x86/include/asm/processor.h | 1 + arch/x86/kernel/rtc.c | 3 +++ arch/x86/lguest/boot.c | 1 + arch/x86/xen/enlighten.c | 4 +++- 6 files changed, 19 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index d143bfa..d0791ac 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -19,6 +19,12 @@ static inline int paravirt_enabled(void) return pv_info.paravirt_enabled; } +static inline int paravirt_has_feature(unsigned int feature) +{ + WARN_ON_ONCE(!pv_info.paravirt_enabled); + return (pv_info.features & feature); +} + static inline void load_sp0(struct tss_struct *tss, struct thread_struct *thread) { diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index a6b8f9f..af3b3b7 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -70,9 +70,14 @@ struct pv_info { #endif int paravirt_enabled; + unsigned int features; /* valid only if paravirt_enabled is set */ const char *name; }; +#define paravirt_has(x) paravirt_has_feature(PV_SUPPORTED_##x) +/* Supported features */ +#define PV_SUPPORTED_RTC (1<<0) + struct pv_init_ops { /* * Patch may replace one of the defined code sequences with diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 944f178..9b3bb51 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -478,6 +478,7 @@ static inline unsigned long current_top_of_stack(void) #else #define __cpuid native_cpuid #define paravirt_enabled() 0 +#define paravirt_has(x) 0 static inline void load_sp0(struct tss_struct *tss, struct thread_struct *thread) diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c index cd96852..4af8d06 100644 --- a/arch/x86/kernel/rtc.c +++ b/arch/x86/kernel/rtc.c @@ -200,6 +200,9 @@ static __init int add_rtc_cmos(void) } #endif + if (paravirt_enabled() && !paravirt_has(RTC)) + return -ENODEV; + platform_device_register(&rtc_device); dev_info(&rtc_device.dev, "registered platform RTC device (no PNP device found)\n"); diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index f2dc08c..5c4792e 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -1419,6 +1419,7 @@ __init void lguest_init(void) pv_info.kernel_rpl = 1; /* Everyone except Xen runs with this set. */ pv_info.shared_kernel_pmd = 1; + pv_info.features = 0; /* * We set up all the lguest overrides for sensitive operations. These diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 3cebc65..f83c0ba 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1186,7 +1186,7 @@ static const struct pv_info xen_info __initconst = { #ifdef CONFIG_X86_64 .extra_user_64bit_cs = FLAT_USER_CS64, #endif - + .features = 0, .name = "Xen", }; @@ -1528,6 +1528,8 @@ asmlinkage __visible void __init xen_start_kernel(void) /* Install Xen paravirt ops */ pv_info = xen_info; + if (xen_initial_domain()) + pv_info.features |= PV_SUPPORTED_RTC; pv_init_ops = xen_init_ops; pv_apic_ops = xen_apic_ops; if (!xen_pvh_domain()) {