* [Qemu-devel] [PATCH] target-i386: do not read/write MSR_TSC_AUX from KVM if CPUID bit is not set
@ 2016-03-30 20:59 Paolo Bonzini
2016-03-31 12:56 ` Laszlo Ersek
2016-03-31 16:26 ` [Qemu-devel] " Eduardo Habkost
0 siblings, 2 replies; 8+ messages in thread
From: Paolo Bonzini @ 2016-03-30 20:59 UTC (permalink / raw)
To: qemu-devel; +Cc: ehabkost, qemu-stable
KVM does not let you read or write this MSR if the corresponding CPUID
bit is not set. This in turn causes MSRs that come after MSR_TSC_AUX
to be ignored by KVM_SET_MRSS.
One visible symptom is that s3.flat from kvm-unit-tests fails with
CPUs that do not have RDTSCP, because the SMBASE is not reset to
0x30000 after reset.
Fixes: c9b8f6b6210847b4381c5b2ee172b1c7eb9985d6
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
target-i386/kvm.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 87ab969..19e2d94 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -917,6 +917,9 @@ int kvm_arch_init_vcpu(CPUState *cs)
if (env->features[FEAT_1_EDX] & CPUID_MTRR) {
has_msr_mtrr = true;
}
+ if (!(env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_RDTSCP)) {
+ has_msr_tsc_aux = false;
+ }
return 0;
}
--
2.5.5
^ permalink raw reply related [flat|nested] 8+ messages in thread* Re: [Qemu-devel] [PATCH] target-i386: do not read/write MSR_TSC_AUX from KVM if CPUID bit is not set
2016-03-30 20:59 [Qemu-devel] [PATCH] target-i386: do not read/write MSR_TSC_AUX from KVM if CPUID bit is not set Paolo Bonzini
@ 2016-03-31 12:56 ` Laszlo Ersek
2016-03-31 13:12 ` [Qemu-devel] [Qemu-stable] " Peter Lieven
2016-03-31 16:26 ` [Qemu-devel] " Eduardo Habkost
1 sibling, 1 reply; 8+ messages in thread
From: Laszlo Ersek @ 2016-03-31 12:56 UTC (permalink / raw)
To: Paolo Bonzini, qemu-devel; +Cc: ehabkost, qemu-stable
On 03/30/16 22:59, Paolo Bonzini wrote:
> KVM does not let you read or write this MSR if the corresponding CPUID
> bit is not set. This in turn causes MSRs that come after MSR_TSC_AUX
> to be ignored by KVM_SET_MRSS.
typo: KVM_SET_MRSS / KVM_SET_MSRS
Thanks for fixing this.
Laszlo
>
> One visible symptom is that s3.flat from kvm-unit-tests fails with
> CPUs that do not have RDTSCP, because the SMBASE is not reset to
> 0x30000 after reset.
>
> Fixes: c9b8f6b6210847b4381c5b2ee172b1c7eb9985d6
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> target-i386/kvm.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> index 87ab969..19e2d94 100644
> --- a/target-i386/kvm.c
> +++ b/target-i386/kvm.c
> @@ -917,6 +917,9 @@ int kvm_arch_init_vcpu(CPUState *cs)
> if (env->features[FEAT_1_EDX] & CPUID_MTRR) {
> has_msr_mtrr = true;
> }
> + if (!(env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_RDTSCP)) {
> + has_msr_tsc_aux = false;
> + }
>
> return 0;
> }
>
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [Qemu-devel] [Qemu-stable] [PATCH] target-i386: do not read/write MSR_TSC_AUX from KVM if CPUID bit is not set
2016-03-31 12:56 ` Laszlo Ersek
@ 2016-03-31 13:12 ` Peter Lieven
2016-03-31 13:23 ` Paolo Bonzini
0 siblings, 1 reply; 8+ messages in thread
From: Peter Lieven @ 2016-03-31 13:12 UTC (permalink / raw)
To: Laszlo Ersek, Paolo Bonzini, qemu-devel
Cc: Michael Roth, ehabkost, qemu-stable
Am 31.03.2016 um 14:56 schrieb Laszlo Ersek:
> On 03/30/16 22:59, Paolo Bonzini wrote:
>> KVM does not let you read or write this MSR if the corresponding CPUID
>> bit is not set. This in turn causes MSRs that come after MSR_TSC_AUX
>> to be ignored by KVM_SET_MRSS.
Is it possible that this causes a freeze when migrating vom qemu 2.2.0 to 2.5.1?
Thanks,
Peter
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Qemu-devel] [Qemu-stable] [PATCH] target-i386: do not read/write MSR_TSC_AUX from KVM if CPUID bit is not set
2016-03-31 13:12 ` [Qemu-devel] [Qemu-stable] " Peter Lieven
@ 2016-03-31 13:23 ` Paolo Bonzini
2016-03-31 15:38 ` Peter Lieven
0 siblings, 1 reply; 8+ messages in thread
From: Paolo Bonzini @ 2016-03-31 13:23 UTC (permalink / raw)
To: Peter Lieven, Laszlo Ersek, qemu-devel
Cc: Michael Roth, ehabkost, qemu-stable
On 31/03/2016 15:12, Peter Lieven wrote:
>>
>>> KVM does not let you read or write this MSR if the corresponding CPUID
>>> bit is not set. This in turn causes MSRs that come after MSR_TSC_AUX
>>> to be ignored by KVM_SET_MRSS.
>
> Is it possible that this causes a freeze when migrating vom qemu 2.2.0
> to 2.5.1?
I wouldn't exclude it if the CPU model is Westmere or earlier.
Paolo
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Qemu-devel] [Qemu-stable] [PATCH] target-i386: do not read/write MSR_TSC_AUX from KVM if CPUID bit is not set
2016-03-31 13:23 ` Paolo Bonzini
@ 2016-03-31 15:38 ` Peter Lieven
2016-03-31 16:52 ` Paolo Bonzini
0 siblings, 1 reply; 8+ messages in thread
From: Peter Lieven @ 2016-03-31 15:38 UTC (permalink / raw)
To: Paolo Bonzini
Cc: Michael Roth, qemu-stable, Laszlo Ersek, qemu-devel, ehabkost
> Am 31.03.2016 um 15:23 schrieb Paolo Bonzini <pbonzini@redhat.com>:
>
>
>
>> On 31/03/2016 15:12, Peter Lieven wrote:
>>>>
>>>> KVM does not let you read or write this MSR if the corresponding CPUID
>>>> bit is not set. This in turn causes MSRs that come after MSR_TSC_AUX
>>>> to be ignored by KVM_SET_MRSS.
>>
>> Is it possible that this causes a freeze when migrating vom qemu 2.2.0
>> to 2.5.1?
>
> I wouldn't exclude it if the CPU model is Westmere or earlier.
the Host CPU or the Emulated CPU?
We emulate Westmere and have also some old blades with Westmere CPUs.
anyway, i give this a try.
Michael, this should have gone into 2.5.1 i think...
Thanks,
Peter
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Qemu-devel] [Qemu-stable] [PATCH] target-i386: do not read/write MSR_TSC_AUX from KVM if CPUID bit is not set
2016-03-31 15:38 ` Peter Lieven
@ 2016-03-31 16:52 ` Paolo Bonzini
2016-03-31 19:21 ` Peter Lieven
0 siblings, 1 reply; 8+ messages in thread
From: Paolo Bonzini @ 2016-03-31 16:52 UTC (permalink / raw)
To: Peter Lieven
Cc: qemu-devel, Laszlo Ersek, Michael Roth, ehabkost, qemu-stable
On 31/03/2016 17:38, Peter Lieven wrote:
>
>
>> Am 31.03.2016 um 15:23 schrieb Paolo Bonzini <pbonzini@redhat.com>:
>>
>>
>>
>>> On 31/03/2016 15:12, Peter Lieven wrote:
>>>>>
>>>>> KVM does not let you read or write this MSR if the corresponding CPUID
>>>>> bit is not set. This in turn causes MSRs that come after MSR_TSC_AUX
>>>>> to be ignored by KVM_SET_MRSS.
>>>
>>> Is it possible that this causes a freeze when migrating vom qemu 2.2.0
>>> to 2.5.1?
>>
>> I wouldn't exclude it if the CPU model is Westmere or earlier.
>
> the Host CPU or the Emulated CPU?
The guest.
Paolo
> We emulate Westmere and have also some old blades with Westmere CPUs.
>
> anyway, i give this a try.
>
> Michael, this should have gone into 2.5.1 i think...
>
> Thanks,
> Peter
>
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Qemu-devel] [Qemu-stable] [PATCH] target-i386: do not read/write MSR_TSC_AUX from KVM if CPUID bit is not set
2016-03-31 16:52 ` Paolo Bonzini
@ 2016-03-31 19:21 ` Peter Lieven
0 siblings, 0 replies; 8+ messages in thread
From: Peter Lieven @ 2016-03-31 19:21 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: qemu-stable, Laszlo Ersek, qemu-devel, ehabkost
Am 31.03.2016 um 18:52 schrieb Paolo Bonzini:
>
> On 31/03/2016 17:38, Peter Lieven wrote:
>>
>>> Am 31.03.2016 um 15:23 schrieb Paolo Bonzini <pbonzini@redhat.com>:
>>>
>>>
>>>
>>>> On 31/03/2016 15:12, Peter Lieven wrote:
>>>>>> KVM does not let you read or write this MSR if the corresponding CPUID
>>>>>> bit is not set. This in turn causes MSRs that come after MSR_TSC_AUX
>>>>>> to be ignored by KVM_SET_MRSS.
>>>> Is it possible that this causes a freeze when migrating vom qemu 2.2.0
>>>> to 2.5.1?
>>> I wouldn't exclude it if the CPU model is Westmere or earlier.
>> the Host CPU or the Emulated CPU?
> The guest.
I can confirm this seems to fix the migration for emulated Westmere CPUs. Regardless if its a 2.2.0 -> 2.5.1 or 2.5.1 -> 2.5.1
migration.
Peter
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Qemu-devel] [PATCH] target-i386: do not read/write MSR_TSC_AUX from KVM if CPUID bit is not set
2016-03-30 20:59 [Qemu-devel] [PATCH] target-i386: do not read/write MSR_TSC_AUX from KVM if CPUID bit is not set Paolo Bonzini
2016-03-31 12:56 ` Laszlo Ersek
@ 2016-03-31 16:26 ` Eduardo Habkost
1 sibling, 0 replies; 8+ messages in thread
From: Eduardo Habkost @ 2016-03-31 16:26 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: qemu-devel, qemu-stable
On Wed, Mar 30, 2016 at 10:59:42PM +0200, Paolo Bonzini wrote:
> KVM does not let you read or write this MSR if the corresponding CPUID
> bit is not set. This in turn causes MSRs that come after MSR_TSC_AUX
> to be ignored by KVM_SET_MRSS.
>
> One visible symptom is that s3.flat from kvm-unit-tests fails with
> CPUs that do not have RDTSCP, because the SMBASE is not reset to
> 0x30000 after reset.
>
> Fixes: c9b8f6b6210847b4381c5b2ee172b1c7eb9985d6
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
--
Eduardo
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2016-03-31 19:22 UTC | newest]
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2016-03-30 20:59 [Qemu-devel] [PATCH] target-i386: do not read/write MSR_TSC_AUX from KVM if CPUID bit is not set Paolo Bonzini
2016-03-31 12:56 ` Laszlo Ersek
2016-03-31 13:12 ` [Qemu-devel] [Qemu-stable] " Peter Lieven
2016-03-31 13:23 ` Paolo Bonzini
2016-03-31 15:38 ` Peter Lieven
2016-03-31 16:52 ` Paolo Bonzini
2016-03-31 19:21 ` Peter Lieven
2016-03-31 16:26 ` [Qemu-devel] " Eduardo Habkost
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