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[98.239.145.235]) by smtp.gmail.com with ESMTPSA id b3sm2002837qte.85.2020.11.05.16.35.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Nov 2020 16:35:42 -0800 (PST) X-Outflank-Mailman: Message body and most headers restored to incoming version 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: 24a5d140-b925-4246-ad47-1ba62707fb0c DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1604622945; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=8cFssZ0LJiNsdeVizgTqZXbeUskMHHnTsA2koKzQk4Y=; b=Rpp4WvTmcBGh64Tds/KVDD8VVVW9x9VBu7eFzTva6HReuDQPLBPxaOIo4/CNlQOcQQCYJY tXkT7sli7AQeKDyNg7NahYvSVdpSn74HfVWvibvZi6S7JG8vs2FX3StUENabFYEGF/szQz v/DvUkW6Qs2FFQAUJRXZ/PZnQ9R8FlU= X-MC-Unique: oBfxYjUMOlOlj2Sr5S426Q-1 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:mime-version :content-transfer-encoding; bh=8cFssZ0LJiNsdeVizgTqZXbeUskMHHnTsA2koKzQk4Y=; b=pawlFFp99l74iiahRy94bE3jGq8P33UQ669zMHLYCHQ146US5ZAXrQBmnY4CWH5124 yUVFeUJ1GbVrS9nb1YSixeViYTXfbdFScDacyByXIGgLNKAmRvMJDz5A2MI4q5J1K8uw KZFvB8hLbPze969f8pN42EmFUxJNKvXSyNM8OgpGCkJyPvDJa0H+war7JKrouqRraQva epcfcs+4rx24I5W0X86jQX8/PbDCHDMBPhGZvu4yLVzqAkA8+uefkdYU2BFCmmmH7sBw OZc0t2/7UDSo2Ubpx9dTEHp/xWxgCTM5hQFO9jm+ruzdyXBo/Z1PgBGryc1kZkhdiNQI /WzA== X-Gm-Message-State: AOAM530/rL3aons88OGrXcu0dYi7qr4Cx+LA2ABklvR51F0EUr6y+SdP wYnK4hC/KQH8sGZYDd6k3e9vdEYM8/F2QFhi6j3j8x0rsNXfn7FRwwoGFuSmAn45nI+iHT6yAw7 4/EUazCzQ0NKmEvdP4QZD4Wq56ZE= X-Received: by 2002:a37:617:: with SMTP id 23mr4692633qkg.256.1604622943547; Thu, 05 Nov 2020 16:35:43 -0800 (PST) X-Google-Smtp-Source: ABdhPJxcXHlYQXweZgP7+K8o61FNzv2e/Th67Tuvn2dyHTEh2Lw53WCzH/qHH2/nUUSBWuJ16IKdJg== X-Received: by 2002:a37:617:: with SMTP id 23mr4692615qkg.256.1604622943297; Thu, 05 Nov 2020 16:35:43 -0800 (PST) From: Brian Masney To: boris.ostrovsky@oracle.com, jgross@suse.com, sstabellini@kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, dustymabe@redhat.com Subject: [PATCH] x86/xen: fix warning when running with nosmt mitigations Date: Thu, 5 Nov 2020 19:35:29 -0500 Message-Id: <20201106003529.391649-1-bmasney@redhat.com> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=bmasney@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @redhat.com) Content-Type: text/plain; charset="utf-8" When booting a hyperthreaded system with the kernel parameter 'mitigations=3Dauto,nosmt', the following warning occurs: WARNING: CPU: 0 PID: 1 at drivers/xen/events/events_base.c:1112 unbind_= from_irqhandler+0x4e/0x60 ... Hardware name: Xen HVM domU, BIOS 4.2.amazon 08/24/2006 ... Call Trace: xen_uninit_lock_cpu+0x28/0x62 xen_hvm_cpu_die+0x21/0x30 takedown_cpu+0x9c/0xe0 ? trace_suspend_resume+0x60/0x60 cpuhp_invoke_callback+0x9a/0x530 _cpu_up+0x11a/0x130 cpu_up+0x7e/0xc0 bringup_nonboot_cpus+0x48/0x50 smp_init+0x26/0x79 kernel_init_freeable+0xea/0x229 ? rest_init+0xaa/0xaa kernel_init+0xa/0x106 ret_from_fork+0x35/0x40 The secondary CPUs are not activated with the nosmt mitigations and only the primary thread on each CPU core is used. In this situation, xen_hvm_smp_prepare_cpus(), and more importantly xen_init_lock_cpu(), is not called, so the lock_kicker_irq is not initialized for the secondary CPUs. Let's fix this by exiting early in xen_uninit_lock_cpu() if the irq is not set to avoid the warning from above for each secondary CPU. Signed-off-by: Brian Masney --- arch/x86/xen/spinlock.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c index 799f4eba0a62..4a052459a08e 100644 --- a/arch/x86/xen/spinlock.c +++ b/arch/x86/xen/spinlock.c @@ -93,9 +93,24 @@ void xen_init_lock_cpu(int cpu) =20 void xen_uninit_lock_cpu(int cpu) { + int irq; + if (!xen_pvspin) return; =20 + /* + * When booting the kernel with 'mitigations=3Dauto,nosmt', the secondary + * CPUs are not activated and only the primary thread on each CPU core + * is used. In this situation, xen_hvm_smp_prepare_cpus(), and more + * importantly xen_init_lock_cpu(), is not called, so the + * lock_kicker_irq is not initialized for the secondary CPUs. Let's + * exit early if the irq is not set to avoid a warning in the console + * log. + */ + irq =3D per_cpu(lock_kicker_irq, cpu); + if (irq =3D=3D -1) + return; + unbind_from_irqhandler(per_cpu(lock_kicker_irq, cpu), NULL); per_cpu(lock_kicker_irq, cpu) =3D -1; kfree(per_cpu(irq_name, cpu)); --=20 2.26.2