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 <zhao1....@intel.com>
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 <zhao1....@intel.com>
---
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.
