On Fri, Jun 07, 2024 at 03:47:01PM +0800, Xiaoyao Li wrote: > Date: Fri, 7 Jun 2024 15:47:01 +0800 > From: Xiaoyao Li <xiaoyao...@intel.com> > Subject: Re: [PATCH] i386/apic: Add hint on boot failure because of > disabling x2APIC > > On 6/7/2024 3:46 PM, Zhao Liu wrote: > > Hi Philippe, > > > > On Fri, Jun 07, 2024 at 08:17:36AM +0200, Philippe Mathieu-Daudé wrote: > > > Date: Fri, 7 Jun 2024 08:17:36 +0200 > > > From: Philippe Mathieu-Daudé <phi...@linaro.org> > > > Subject: Re: [PATCH] i386/apic: Add hint on boot failure because of > > > disabling x2APIC > > > > > > On 6/6/24 16:08, Zhao Liu wrote: > > > > Currently, the Q35 supports up to 4096 vCPUs (since v9.0), but for TCG > > > > cases, if x2APIC is not actively enabled to boot more than 255 vCPUs ( > > why bother mentioning TCG case?
I'm restating the problem scenario for this error message. This is a common use case, which is enough to support adding a simple hint. > you below example is not for TCG. Not? > And the issue is not caused by TCG but > default cpu model doesn't have X2APIC enabled. This is not an issue, and it is normal to report an error in current QEMU. > > > > e.g., qemu-system-i386 -M pc-q35-9.0 -smp 666), the following error is > > > > reported: > > > > > > > > Unexpected error in apic_common_set_id() at > > > > ../hw/intc/apic_common.c:449: > > > > qemu-system-i386: APIC ID 255 requires x2APIC feature in CPU > > > > Aborted (core dumped) > > > > > > > > This error can be resolved by setting x2apic=on in -cpu. In order to > > > > better help users deal with this scenario, add the error hint to > > > > instruct users on how to enable the x2apic feature. > > > > > > Why not automatically set x2apic=on in this case instead? > > > > The default CPU model is qemu64 without x2APIC. I think it might be > > necessary to update the version to add x2APIC in qemu64, and I'd like to > > look into it again for any other potential issues. > > > > In addition to adding x2APIC directly to the qemu64, this hint can also > > help some users who want a large number of vCPUs based on other older > > CPU models. Though, it's not very common but this hint would be helpful. > > > > > > Then, the error > > > > report becomes the following: > > > > > > > > Unexpected error in apic_common_set_id() at > > > > ../hw/intc/apic_common.c:448: > > > > qemu-system-i386: APIC ID 255 requires x2APIC feature in CPU > > > > Try x2apic=on in -cpu. > > > > Aborted (core dumped) > > > > > > > > Note since @errp is &error_abort, error_append_hint() can't be applied > > > > on @errp. And in order to separate the exact error message from the > > > > (perhaps effectively) hint, adding a hint via error_append_hint() is > > > > also necessary. Therefore, introduce @local_error in > > > > apic_common_set_id() to handle both the error message and the error > > > > hint. > > > > > > > > Suggested-by: Philippe Mathieu-Daudé <phi...@linaro.org> > > > > Signed-off-by: Zhao Liu <zhao1....@intel.com> > > > > --- > > > > hw/intc/apic_common.c | 7 ++++++- > > > > 1 file changed, 6 insertions(+), 1 deletion(-) > > > > > > Reviewed-by: Philippe Mathieu-Daudé <phi...@linaro.org> > > > > Thanks! > > > > >
