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Tsirkin" Cc: Zhao Liu , Paolo Bonzini , Peter Maydell , qemu-devel@nongnu.org, Zhao Liu , Ani Sinha , Igor Mammedov References: <20240412085358.731560-1-zhao1.liu@linux.intel.com> <305d659b-d4d6-4681-bdad-cd869e552333@linaro.org> <20240602092857-mutt-send-email-mst@kernel.org> Content-Language: en-US From: =?UTF-8?Q?Philippe_Mathieu-Daud=C3=A9?= In-Reply-To: <20240602092857-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2a00:1450:4864:20::62f; envelope-from=philmd@linaro.org; helo=mail-ej1-x62f.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Hi Michael, On 2/6/24 15:30, Michael S. Tsirkin wrote: > On Fri, Apr 12, 2024 at 11:57:35AM +0200, Philippe Mathieu-Daudé wrote: >> Hi Zhao, >> >> On 12/4/24 10:53, Zhao Liu wrote: >>> From: Zhao Liu >>> >>> Commit e4e98c7eebfa ("pc: q35: Bump max_cpus to 4096 vcpus") increases >>> the supported CPUs for PC Q35 machine. >>> >>> Update maximum CPU numbers for PC Q35 in the document. >>> >>> Signed-off-by: Zhao Liu >>> --- >>> docs/system/target-i386-desc.rst.inc | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/docs/system/target-i386-desc.rst.inc b/docs/system/target-i386-desc.rst.inc >>> index 5ebbcda9db4c..319e540573d3 100644 >>> --- a/docs/system/target-i386-desc.rst.inc >>> +++ b/docs/system/target-i386-desc.rst.inc >>> @@ -36,7 +36,7 @@ The QEMU PC System emulator simulates the following peripherals: >>> - PCI UHCI, OHCI, EHCI or XHCI USB controller and a virtual USB-1.1 >>> hub. >>> -SMP is supported with up to 255 CPUs. >>> +SMP is supported with up to 255 CPUs (and 4096 CPUs for PC Q35 machine). >> >> This comment is not accurate since a while, IIUC: >> >> Up to q35-2.7: 255 >> q35-2.8: 288 >> q35-8.0+: 1024 >> q35-9.0: 4096 > > > What are you saying here, Philippe? I don't think compat > machine types matter enough to bother with more detail. My point is I find this description confusing w.r.t. how QEMU behaves: $ qemu-system-i386 -M pc-q35-2.8 -smp 666 qemu-system-i386: Invalid SMP CPUs 666. The max CPUs supported by machine 'pc-q35-2.8' is 288 $ qemu-system-i386 -M pc-q35-8.0 -smp 666 qemu-system-i386: Invalid SMP CPUs 666. The max CPUs supported by machine 'pc-q35-8.0' is 288 $ qemu-system-i386 -M pc-q35-9.0 -smp 666 Unexpected error in apic_common_set_id() at ../hw/intc/apic_common.c:447: qemu-system-i386: APIC ID 255 requires x2APIC feature in CPU Abort trap: 6 I'd rather at least: "SMP is supported with up to 255 CPUs (and since v9.0: 4096 CPUs for PC Q35 machine)." or: "SMP is supported with up to 255 CPUs (and 4096 CPUs for PC Q35 machine since v9.0)." >>> QEMU uses the PC BIOS from the Seabios project and the Plex86/Bochs LGPL >>> VGA BIOS. >