* [PATCH] KVM: SVM: compile out AVIC if !CONFIG_X86_LOCAL_APIC
@ 2016-06-14 16:40 Paolo Bonzini
2016-06-14 18:20 ` Suravee Suthikulanit
0 siblings, 1 reply; 6+ messages in thread
From: Paolo Bonzini @ 2016-06-14 16:40 UTC (permalink / raw)
To: linux-kernel, kvm; +Cc: Suravee Suthikulpanit, rkrcmar
AVIC needs __default_cpu_present_to_apicid. Stub out all functions
that use it, and disable the module parameter, if Linux is
compiled without local APIC support.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/svm.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 1163e8173e5a..b70bc98269f0 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -238,7 +238,9 @@ module_param(nested, int, S_IRUGO);
/* enable / disable AVIC */
static int avic;
+#ifdef CONFIG_X86_LOCAL_APIC
module_param(avic, int, S_IRUGO);
+#endif
static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0);
static void svm_flush_tlb(struct kvm_vcpu *vcpu);
@@ -1323,6 +1325,7 @@ free_avic:
*/
static void avic_set_running(struct kvm_vcpu *vcpu, bool is_run)
{
+#ifdef CONFIG_X86_LOCAL_APIC
u64 entry;
int h_physical_id = __default_cpu_present_to_apicid(vcpu->cpu);
struct vcpu_svm *svm = to_svm(vcpu);
@@ -1343,10 +1346,12 @@ static void avic_set_running(struct kvm_vcpu *vcpu, bool is_run)
if (is_run)
entry |= AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
+#endif
}
static void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
+#ifdef CONFIG_X86_LOCAL_APIC
u64 entry;
/* ID = 0xff (broadcast), ID > 0xff (reserved) */
int h_physical_id = __default_cpu_present_to_apicid(cpu);
@@ -1369,10 +1374,12 @@ static void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
entry |= AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
+#endif
}
static void avic_vcpu_put(struct kvm_vcpu *vcpu)
{
+#ifdef CONFIG_X86_LOCAL_APIC
u64 entry;
struct vcpu_svm *svm = to_svm(vcpu);
@@ -1382,6 +1389,7 @@ static void avic_vcpu_put(struct kvm_vcpu *vcpu)
entry = READ_ONCE(*(svm->avic_physical_id_cache));
entry &= ~AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
+#endif
}
static void svm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
@@ -4231,6 +4239,7 @@ static void svm_sync_pir_to_irr(struct kvm_vcpu *vcpu)
static void svm_deliver_avic_intr(struct kvm_vcpu *vcpu, int vec)
{
+#ifdef CONFIG_X86_LOCAL_APIC
kvm_lapic_set_irr(vec, vcpu->arch.apic);
smp_mb__after_atomic();
@@ -4239,6 +4248,9 @@ static void svm_deliver_avic_intr(struct kvm_vcpu *vcpu, int vec)
__default_cpu_present_to_apicid(vcpu->cpu));
else
kvm_vcpu_wake_up(vcpu);
+#else
+ WARN_ON_ONCE(1);
+#endif
}
static int svm_nmi_allowed(struct kvm_vcpu *vcpu)
--
1.8.3.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] KVM: SVM: compile out AVIC if !CONFIG_X86_LOCAL_APIC
2016-06-14 16:40 [PATCH] KVM: SVM: compile out AVIC if !CONFIG_X86_LOCAL_APIC Paolo Bonzini
@ 2016-06-14 18:20 ` Suravee Suthikulanit
2016-06-14 21:22 ` Paolo Bonzini
0 siblings, 1 reply; 6+ messages in thread
From: Suravee Suthikulanit @ 2016-06-14 18:20 UTC (permalink / raw)
To: Paolo Bonzini, linux-kernel, kvm; +Cc: rkrcmar
Hi Paolo,
On 6/14/2016 11:40 AM, Paolo Bonzini wrote:
> AVIC needs __default_cpu_present_to_apicid. Stub out all functions
> that use it, and disable the module parameter, if Linux is
> compiled without local APIC support.
I think you are right that we should disable AVIC #ifndef
CONFIG_X86_LOCAL_APIC. However, do you think we should just use
default_cpu_present_to_apicid() instead of the
__default_cpu_present_to_apicid()? This way, we can avoid having #ifdef
CONFIG_X86_LOCAL_APIC in multiple places.
As for disabling AVIC, I think we can also do:
if (!IS_ENABLED(CONFIG_X86_LOCAL_APIC))
avic = false;
What do you think?
Thanks,
Suravee
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] KVM: SVM: compile out AVIC if !CONFIG_X86_LOCAL_APIC
2016-06-14 18:20 ` Suravee Suthikulanit
@ 2016-06-14 21:22 ` Paolo Bonzini
2016-06-14 21:44 ` Suravee Suthikulanit
0 siblings, 1 reply; 6+ messages in thread
From: Paolo Bonzini @ 2016-06-14 21:22 UTC (permalink / raw)
To: Suravee Suthikulanit; +Cc: linux-kernel, kvm, rkrcmar
----- Original Message -----
> From: "Suravee Suthikulanit" <suravee.suthikulpanit@amd.com>
> To: "Paolo Bonzini" <pbonzini@redhat.com>, linux-kernel@vger.kernel.org, kvm@vger.kernel.org
> Cc: rkrcmar@redhat.com
> Sent: Tuesday, June 14, 2016 8:20:30 PM
> Subject: Re: [PATCH] KVM: SVM: compile out AVIC if !CONFIG_X86_LOCAL_APIC
>
> Hi Paolo,
>
> On 6/14/2016 11:40 AM, Paolo Bonzini wrote:
> > AVIC needs __default_cpu_present_to_apicid. Stub out all functions
> > that use it, and disable the module parameter, if Linux is
> > compiled without local APIC support.
>
> I think you are right that we should disable AVIC #ifndef
> CONFIG_X86_LOCAL_APIC. However, do you think we should just use
> default_cpu_present_to_apicid() instead of the
> __default_cpu_present_to_apicid()?
I'm not sure why that would help? default_cpu_present_to_apicid
is also declared only if CONFIG_X86_LOCAL_APIC is defined.
> As for disabling AVIC, I think we can also do:
>
> if (!IS_ENABLED(CONFIG_X86_LOCAL_APIC))
> avic = false;
Yes, we'll need to do that once AVIC is enabled by default; or
static bool avic = IS_ENABLED(CONFIG_X86_LOCAL_APIC);
In any case the module parameter must be hidden if there's no
support in the kernel for the local APIC.
Paolo
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] KVM: SVM: compile out AVIC if !CONFIG_X86_LOCAL_APIC
2016-06-14 21:22 ` Paolo Bonzini
@ 2016-06-14 21:44 ` Suravee Suthikulanit
2016-06-14 22:01 ` Paolo Bonzini
0 siblings, 1 reply; 6+ messages in thread
From: Suravee Suthikulanit @ 2016-06-14 21:44 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: linux-kernel, kvm, rkrcmar
On 6/14/2016 4:22 PM, Paolo Bonzini wrote:
> ----- Original Message -----
>> From: "Suravee Suthikulanit" <suravee.suthikulpanit@amd.com>
>> To: "Paolo Bonzini" <pbonzini@redhat.com>, linux-kernel@vger.kernel.org, kvm@vger.kernel.org
>> Cc: rkrcmar@redhat.com
>> Sent: Tuesday, June 14, 2016 8:20:30 PM
>> Subject: Re: [PATCH] KVM: SVM: compile out AVIC if !CONFIG_X86_LOCAL_APIC
>>
>> Hi Paolo,
>>
>> On 6/14/2016 11:40 AM, Paolo Bonzini wrote:
>>> AVIC needs __default_cpu_present_to_apicid. Stub out all functions
>>> that use it, and disable the module parameter, if Linux is
>>> compiled without local APIC support.
>>
>> I think you are right that we should disable AVIC #ifndef
>> CONFIG_X86_LOCAL_APIC. However, do you think we should just use
>> default_cpu_present_to_apicid() instead of the
>> __default_cpu_present_to_apicid()?
>
> I'm not sure why that would help? default_cpu_present_to_apicid
> is also declared only if CONFIG_X86_LOCAL_APIC is defined.
Actually, I also meant to include the change that I sent out
(https://lkml.org/lkml/2016/6/13/898), which declares a dummy for the
case #ifndef CONFIG_X86_LOCAL_APIC. That should help with the issue here.
>> As for disabling AVIC, I think we can also do:
>>
>> if (!IS_ENABLED(CONFIG_X86_LOCAL_APIC))
>> avic = false;
>
> Yes, we'll need to do that once AVIC is enabled by default; or
>
> static bool avic = IS_ENABLED(CONFIG_X86_LOCAL_APIC);
>
> In any case the module parameter must be hidden if there's no
> support in the kernel for the local APIC.
>
> Paolo
>
Agree.
If you okay with using default_cpu_present_to_apicid(), I can send out
the v2 of the "[PATCH] x86/SVM: Fix implicit declaration issue for
__default_cpu_present_to_apicid()" with changes that you suggested here.
Thanks,
Suravee
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] KVM: SVM: compile out AVIC if !CONFIG_X86_LOCAL_APIC
2016-06-14 21:44 ` Suravee Suthikulanit
@ 2016-06-14 22:01 ` Paolo Bonzini
2016-06-14 22:09 ` Suravee Suthikulanit
0 siblings, 1 reply; 6+ messages in thread
From: Paolo Bonzini @ 2016-06-14 22:01 UTC (permalink / raw)
To: Suravee Suthikulanit; +Cc: linux-kernel, kvm, rkrcmar
On 14/06/2016 23:44, Suravee Suthikulanit wrote:
> On 6/14/2016 4:22 PM, Paolo Bonzini wrote:
>> ----- Original Message -----
>>> From: "Suravee Suthikulanit" <suravee.suthikulpanit@amd.com>
>>> To: "Paolo Bonzini" <pbonzini@redhat.com>,
>>> linux-kernel@vger.kernel.org, kvm@vger.kernel.org
>>> Cc: rkrcmar@redhat.com
>>> Sent: Tuesday, June 14, 2016 8:20:30 PM
>>> Subject: Re: [PATCH] KVM: SVM: compile out AVIC if
>>> !CONFIG_X86_LOCAL_APIC
>>>
>>> Hi Paolo,
>>>
>>> On 6/14/2016 11:40 AM, Paolo Bonzini wrote:
>>>> AVIC needs __default_cpu_present_to_apicid. Stub out all functions
>>>> that use it, and disable the module parameter, if Linux is
>>>> compiled without local APIC support.
>>>
>>> I think you are right that we should disable AVIC #ifndef
>>> CONFIG_X86_LOCAL_APIC. However, do you think we should just use
>>> default_cpu_present_to_apicid() instead of the
>>> __default_cpu_present_to_apicid()?
>>
>> I'm not sure why that would help? default_cpu_present_to_apicid
>> is also declared only if CONFIG_X86_LOCAL_APIC is defined.
>
> Actually, I also meant to include the change that I sent out
> (https://lkml.org/lkml/2016/6/13/898), which declares a dummy for the
> case #ifndef CONFIG_X86_LOCAL_APIC. That should help with the issue here.
I think it is by design that default_cpu_present_to_apicid() is absent.
Perhaps you could create a kvm_cpu_get_apicid() function that is either
__default_cpu_present_to_apicid() or WARN_ON_ONCE(1)+return 0?
Paolo
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] KVM: SVM: compile out AVIC if !CONFIG_X86_LOCAL_APIC
2016-06-14 22:01 ` Paolo Bonzini
@ 2016-06-14 22:09 ` Suravee Suthikulanit
0 siblings, 0 replies; 6+ messages in thread
From: Suravee Suthikulanit @ 2016-06-14 22:09 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: linux-kernel, kvm, rkrcmar
On 6/14/2016 5:01 PM, Paolo Bonzini wrote:
>
> On 14/06/2016 23:44, Suravee Suthikulanit wrote:
>> > On 6/14/2016 4:22 PM, Paolo Bonzini wrote:
>>> >> ----- Original Message -----
>>>> >>> From: "Suravee Suthikulanit" <suravee.suthikulpanit@amd.com>
>>>> >>> To: "Paolo Bonzini" <pbonzini@redhat.com>,
>>>> >>> linux-kernel@vger.kernel.org, kvm@vger.kernel.org
>>>> >>> Cc: rkrcmar@redhat.com
>>>> >>> Sent: Tuesday, June 14, 2016 8:20:30 PM
>>>> >>> Subject: Re: [PATCH] KVM: SVM: compile out AVIC if
>>>> >>> !CONFIG_X86_LOCAL_APIC
>>>> >>>
>>>> >>> Hi Paolo,
>>>> >>>
>>>> >>> On 6/14/2016 11:40 AM, Paolo Bonzini wrote:
>>>>> >>>> AVIC needs __default_cpu_present_to_apicid. Stub out all functions
>>>>> >>>> that use it, and disable the module parameter, if Linux is
>>>>> >>>> compiled without local APIC support.
>>>> >>>
>>>> >>> I think you are right that we should disable AVIC #ifndef
>>>> >>> CONFIG_X86_LOCAL_APIC. However, do you think we should just use
>>>> >>> default_cpu_present_to_apicid() instead of the
>>>> >>> __default_cpu_present_to_apicid()?
>>> >>
>>> >> I'm not sure why that would help? default_cpu_present_to_apicid
>>> >> is also declared only if CONFIG_X86_LOCAL_APIC is defined.
>> >
>> > Actually, I also meant to include the change that I sent out
>> > (https://lkml.org/lkml/2016/6/13/898), which declares a dummy for the
>> > case #ifndef CONFIG_X86_LOCAL_APIC. That should help with the issue here.
> I think it is by design that default_cpu_present_to_apicid() is absent.
>
> Perhaps you could create a kvm_cpu_get_apicid() function that is either
> __default_cpu_present_to_apicid() or WARN_ON_ONCE(1)+return 0?
>
> Paolo
Ok, I'll do that and send out V2.
Thanks,
Suravee
^ permalink raw reply [flat|nested] 6+ messages in thread
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2016-06-14 16:40 [PATCH] KVM: SVM: compile out AVIC if !CONFIG_X86_LOCAL_APIC Paolo Bonzini
2016-06-14 18:20 ` Suravee Suthikulanit
2016-06-14 21:22 ` Paolo Bonzini
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