On 4/6/24 10:54, Zhao Liu wrote:
On Mon, Jun 03, 2024 at 07:31:47PM +0200, Philippe Mathieu-Daudé wrote:
Date: Mon, 3 Jun 2024 19:31:47 +0200
From: Philippe Mathieu-Daudé <[email protected]>
Subject: Re: [PATCH-for-9.0?] docs: i386: pc: Update maximum CPU numbers
for PC Q35
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 <[email protected]>
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 <[email protected]>
---
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
For tcg, it needs to set x2apic=on in -cpu.
Thanks for clarifying. Using error_append_hint() is certainly
better than aborting or asking on the mailing list (from user
perspective) ;)
Regards,
Phil.
