| Message ID | CAOLK0pz4RPeRfTB3JSHC0H23DVe_1qGZ+Yg0r-gBk+QfkEQCow@mail.gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 2016-02-25 09:33, Lan Tianyu wrote: > 2016-02-20 17:00 GMT+08:00 Paolo Bonzini <pbonzini@redhat.com>: >> >> >> ----- Original Message ----- >>> From: "Jan Kiszka" <jan.kiszka@web.de> >>> To: "Eduardo Habkost" <ehabkost@redhat.com>, "Paolo Bonzini" <pbonzini@redhat.com> >>> Cc: "qemu-devel" <qemu-devel@nongnu.org>, "kvm" <kvm@vger.kernel.org> >>> Sent: Saturday, February 20, 2016 9:09:32 AM >>> Subject: kvm: "warning: host doesn't support requested feature: CPUID.01H:ECX.x2apic [bit 21]" >>> >>> Hi all, >>> >>> I suppose 5120901a37 introduced this: qemu with kernel_irqchip=off now >>> generates these warnings, one per VCPU, during QEMU startup. Is the plan >>> to live with them until we finally have x2APIC emulation in userspace >>> (ie. also MSR vmexiting to there), or should we otherwise avoid it? >> >> I think it's a bug, x2apic should be auto-suppressed with kernel_irqchip=off. >> > > The patch is to fix the issue. > ------------------------------------->8---------------------------- > From 58f2a3a94c8e7bf9f3474bcafb6c59cc4f8bcbd9 Mon Sep 17 00:00:00 2001 > From: Lan Tianyu <tianyu.lan@intel.com> > Date: Sun, 15 Jul 2001 01:40:17 -0400 > Subject: [PATCH] Qemu/KVM: Remove x2apic feature from CPU model when > kernel_irqchip=off > > x2apic feature is in the kvm_default_props and automatically added to all > CPU models when KVM is enabled regardless of kernel_irqchip=off. This will > trigger "warning: host doesn't support requested feature: CPUID.01H: > ECX.x2apic [bit 21]" when kernel_irqchip=off. This patch is to remove x2apic > feature when kernel_irqchip=off. We know this, but it's probably worth to mention the underlying reason here: userspace devices don't support x2APIC. > > Signed-off-by: Lan Tianyu <tianyu.lan@intel.com> > --- > target-i386/cpu.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/target-i386/cpu.c b/target-i386/cpu.c > index 0d447b5..2ec7eb7 100644 > --- a/target-i386/cpu.c > +++ b/target-i386/cpu.c > @@ -2105,6 +2105,9 @@ static void x86_cpu_load_def(X86CPU *cpu, > X86CPUDefinition *def, Error **errp) > > /* Special cases not set in the X86CPUDefinition structs: */ > if (kvm_enabled()) { > + if (!kvm_irqchip_in_kernel()) > + x86_cpu_change_kvm_default("x2apic", "off"); > + > x86_cpu_apply_props(cpu, kvm_default_props); > } > > -- > 1.9.3 > Make sure to comply with the coding style (there is a checkpatch.pl also in QEMU). And please post as a new thread with proper subject, otherwise people (and tools) will not find your patch as such. Jan -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
2016-02-25 16:39 GMT+08:00 Jan Kiszka <jan.kiszka@web.de>: > On 2016-02-25 09:33, Lan Tianyu wrote: >> 2016-02-20 17:00 GMT+08:00 Paolo Bonzini <pbonzini@redhat.com>: >>> >>> >>> ----- Original Message ----- >>>> From: "Jan Kiszka" <jan.kiszka@web.de> >>>> To: "Eduardo Habkost" <ehabkost@redhat.com>, "Paolo Bonzini" <pbonzini@redhat.com> >>>> Cc: "qemu-devel" <qemu-devel@nongnu.org>, "kvm" <kvm@vger.kernel.org> >>>> Sent: Saturday, February 20, 2016 9:09:32 AM >>>> Subject: kvm: "warning: host doesn't support requested feature: CPUID.01H:ECX.x2apic [bit 21]" >>>> >>>> Hi all, >>>> >>>> I suppose 5120901a37 introduced this: qemu with kernel_irqchip=off now >>>> generates these warnings, one per VCPU, during QEMU startup. Is the plan >>>> to live with them until we finally have x2APIC emulation in userspace >>>> (ie. also MSR vmexiting to there), or should we otherwise avoid it? >>> >>> I think it's a bug, x2apic should be auto-suppressed with kernel_irqchip=off. >>> >> >> The patch is to fix the issue. >> ------------------------------------->8---------------------------- >> From 58f2a3a94c8e7bf9f3474bcafb6c59cc4f8bcbd9 Mon Sep 17 00:00:00 2001 >> From: Lan Tianyu <tianyu.lan@intel.com> >> Date: Sun, 15 Jul 2001 01:40:17 -0400 >> Subject: [PATCH] Qemu/KVM: Remove x2apic feature from CPU model when >> kernel_irqchip=off >> >> x2apic feature is in the kvm_default_props and automatically added to all >> CPU models when KVM is enabled regardless of kernel_irqchip=off. This will >> trigger "warning: host doesn't support requested feature: CPUID.01H: >> ECX.x2apic [bit 21]" when kernel_irqchip=off. This patch is to remove x2apic >> feature when kernel_irqchip=off. > > We know this, but it's probably worth to mention the underlying reason > here: userspace devices don't support x2APIC. > >> >> Signed-off-by: Lan Tianyu <tianyu.lan@intel.com> >> --- >> target-i386/cpu.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/target-i386/cpu.c b/target-i386/cpu.c >> index 0d447b5..2ec7eb7 100644 >> --- a/target-i386/cpu.c >> +++ b/target-i386/cpu.c >> @@ -2105,6 +2105,9 @@ static void x86_cpu_load_def(X86CPU *cpu, >> X86CPUDefinition *def, Error **errp) >> >> /* Special cases not set in the X86CPUDefinition structs: */ >> if (kvm_enabled()) { >> + if (!kvm_irqchip_in_kernel()) >> + x86_cpu_change_kvm_default("x2apic", "off"); >> + >> x86_cpu_apply_props(cpu, kvm_default_props); >> } >> >> -- >> 1.9.3 >> > > Make sure to comply with the coding style (there is a checkpatch.pl also > in QEMU). And please post as a new thread with proper subject, otherwise > people (and tools) will not find your patch as such. > > Jan Thanks for comments. Will update soon..
diff --git a/target-i386/cpu.c b/target-i386/cpu.c index 0d447b5..2ec7eb7 100644 --- a/target-i386/cpu.c +++ b/target-i386/cpu.c @@ -2105,6 +2105,9 @@ static void x86_cpu_load_def(X86CPU *cpu, X86CPUDefinition *def, Error **errp) /* Special cases not set in the X86CPUDefinition structs: */ if (kvm_enabled()) { + if (!kvm_irqchip_in_kernel()) + x86_cpu_change_kvm_default("x2apic", "off"); + x86_cpu_apply_props(cpu, kvm_default_props); }