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[37.24.206.209]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a9061330b08sm1210961466b.201.2024.09.23.04.54.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 23 Sep 2024 04:54:43 -0700 (PDT) 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: 9f75d0f5-79a2-11ef-99a2-01e77a169b0f DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1727092483; x=1727697283; darn=lists.xenproject.org; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:from:to:cc:subject:date:message-id:reply-to; bh=Qjlbtj/NrSZzsEAIxXrSppa8c/EYDVy5sCgYGPVesXw=; b=W4ATBLKZRaZU7zm6wpgTTybD4OXmlwz1QdKjq8+BwAJSd1FI2hvL4g206dAMmFIouK +t43WJV07+gGVpidcAeA8oojS27HPjPX5zTVn31iuDeY3xmbiEJ56PxYPPvilZ2AGhRB x4wehRpvNcv3P+tFT9BUvNRGWzmroQtPy4l3I2sLbXgV0RacCItCrQ2WO/AUHpMJiBjM DQSwE95OygBBea/BCiu20iokTzakpoD+ppW1+j0eWjsGFnpE/7ySVpE723Qbi7GNGFSv t8zkMcoVPutM9XwLYmRiCRbaJm/qwiVT7agu5/eo3axlIrZES9kPumyoZ4TNW0zFUvai 8miA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727092483; x=1727697283; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=Qjlbtj/NrSZzsEAIxXrSppa8c/EYDVy5sCgYGPVesXw=; b=vF4rhKYqOZjMsBTFfANJnnlxUnrdkhiY8oJZgyx3HYkJxOAReanq+lY3qeJ2WeP6zD KbYuZ32dCJl6UktmpheQoXOZUPIWs09KjJGObcPhsDg+J8NMkwZkchI5fbEc/qlTMhC9 +mR9piMLeyPx/N0IcUFPcJNyG98gR9R2a2iOB/jqydeFYIIIwjZWQa1z8P2lrf59yAQW odFRywWtbk11aeNznu4iO+jLOebSGJJR0dWr0/REZdOGDARZvonhC86uA1T+aeyEXs3a GNr34bkfwVWUtfGSUg00aomblubQlF2PGat1qtLm17jv1Q92xyDOVYFR7/4FCx6kaIaG RYTA== X-Gm-Message-State: AOJu0Yzi/vm8GDp8eSpDSxm7q4+cyLZI9jSab3uOFXXWjMvfdyl8NrXH vWbq+FwguP6KqdOz/94o+vPnOXtxCCMZjud+nEsWsgyo2PAi2ZLHtc7kJuxhIQ== X-Google-Smtp-Source: AGHT+IGcz1FUpLIsakRavNyX2l9dvA2XgGjgn8y4Kw5AWxz/f87T1QgSkiGoyC4zHrtccUuxKpS1cA== X-Received: by 2002:a17:907:e610:b0:a8d:4b02:334c with SMTP id a640c23a62f3a-a90d5841a3cmr982928666b.64.1727092483359; Mon, 23 Sep 2024 04:54:43 -0700 (PDT) Message-ID: Date: Mon, 23 Sep 2024 13:54:51 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] x86/shutdown: mask LVTERR ahead of offlining CPUs To: =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= Cc: xen-devel@lists.xenproject.org, Andrew Cooper References: <20240919142748.43821-1-roger.pau@citrix.com> <7a6906a2-6860-4575-a88d-90be5ec43eee@citrix.com> Content-Language: en-US From: Jan Beulich Autocrypt: addr=jbeulich@suse.com; keydata= xsDiBFk3nEQRBADAEaSw6zC/EJkiwGPXbWtPxl2xCdSoeepS07jW8UgcHNurfHvUzogEq5xk hu507c3BarVjyWCJOylMNR98Yd8VqD9UfmX0Hb8/BrA+Hl6/DB/eqGptrf4BSRwcZQM32aZK 7Pj2XbGWIUrZrd70x1eAP9QE3P79Y2oLrsCgbZJfEwCgvz9JjGmQqQkRiTVzlZVCJYcyGGsD /0tbFCzD2h20ahe8rC1gbb3K3qk+LpBtvjBu1RY9drYk0NymiGbJWZgab6t1jM7sk2vuf0Py O9Hf9XBmK0uE9IgMaiCpc32XV9oASz6UJebwkX+zF2jG5I1BfnO9g7KlotcA/v5ClMjgo6Gl MDY4HxoSRu3i1cqqSDtVlt+AOVBJBACrZcnHAUSuCXBPy0jOlBhxPqRWv6ND4c9PH1xjQ3NP nxJuMBS8rnNg22uyfAgmBKNLpLgAGVRMZGaGoJObGf72s6TeIqKJo/LtggAS9qAUiuKVnygo 3wjfkS9A3DRO+SpU7JqWdsveeIQyeyEJ/8PTowmSQLakF+3fote9ybzd880fSmFuIEJldWxp Y2ggPGpiZXVsaWNoQHN1c2UuY29tPsJgBBMRAgAgBQJZN5xEAhsDBgsJCAcDAgQVAggDBBYC AwECHgECF4AACgkQoDSui/t3IH4J+wCfQ5jHdEjCRHj23O/5ttg9r9OIruwAn3103WUITZee e7Sbg12UgcQ5lv7SzsFNBFk3nEQQCACCuTjCjFOUdi5Nm244F+78kLghRcin/awv+IrTcIWF hUpSs1Y91iQQ7KItirz5uwCPlwejSJDQJLIS+QtJHaXDXeV6NI0Uef1hP20+y8qydDiVkv6l IreXjTb7DvksRgJNvCkWtYnlS3mYvQ9NzS9PhyALWbXnH6sIJd2O9lKS1Mrfq+y0IXCP10eS FFGg+Av3IQeFatkJAyju0PPthyTqxSI4lZYuJVPknzgaeuJv/2NccrPvmeDg6Coe7ZIeQ8Yj t0ARxu2xytAkkLCel1Lz1WLmwLstV30g80nkgZf/wr+/BXJW/oIvRlonUkxv+IbBM3dX2OV8 AmRv1ySWPTP7AAMFB/9PQK/VtlNUJvg8GXj9ootzrteGfVZVVT4XBJkfwBcpC/XcPzldjv+3 HYudvpdNK3lLujXeA5fLOH+Z/G9WBc5pFVSMocI71I8bT8lIAzreg0WvkWg5V2WZsUMlnDL9 mpwIGFhlbM3gfDMs7MPMu8YQRFVdUvtSpaAs8OFfGQ0ia3LGZcjA6Ik2+xcqscEJzNH+qh8V m5jjp28yZgaqTaRbg3M/+MTbMpicpZuqF4rnB0AQD12/3BNWDR6bmh+EkYSMcEIpQmBM51qM EKYTQGybRCjpnKHGOxG0rfFY1085mBDZCH5Kx0cl0HVJuQKC+dV2ZY5AqjcKwAxpE75MLFkr wkkEGBECAAkFAlk3nEQCGwwACgkQoDSui/t3IH7nnwCfcJWUDUFKdCsBH/E5d+0ZnMQi+G0A nAuWpQkjM1ASeQwSHEeAWPgskBQL In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 20.09.2024 10:35, Roger Pau Monné wrote: > On Thu, Sep 19, 2024 at 10:19:49PM +0200, Andrew Cooper wrote: >> On 19/09/2024 4:27 pm, Roger Pau Monne wrote: >>> @@ -364,6 +369,18 @@ void smp_send_stop(void) >>> fixup_irqs(cpumask_of(cpu), 0); >>> local_irq_enable(); >>> >>> + /* >>> + * Mask the local APIC error vector ahead of stopping CPUs. >>> + * >>> + * On AMD the local APIC will report Receive Accept Errors if the >>> + * destination APIC ID of an interrupt message is not online. There's >>> + * no guarantee that fixup_irqs() will evacuate all interrupts - >>> + * possibly because the sole CPU remaining online doesn't have enough >>> + * vectors to accommodate all. >>> + */ >>> + smp_call_function(mask_lvterr, NULL, true); >>> + mask_lvterr(NULL); >>> + >>> smp_call_function(stop_this_cpu, NULL, 0); >> >> Irrespective of the question over approach, stop_this_cpu() should end >> up clearing LVTERR.  Why doesn't that suffice? > > No, because those are no ordered. The sequence needs to strictly be: > > - Mask LVTERR on all CPUs. > > - Stop CPUs. > > Otherwise CPUs might be stopped before LVTERR has been uniformly > masked, leading to Receive accept error reported on the CPUs that > don't yet have LVTERR masked. Yet fixup_irqs() has moved everything to CPU0. Nothing should go to any of the APs anymore. Fiddling with LVTERR here feels like curing a symptom rather than the root cause. Jan