* [Qemu-devel] [PATCH for-2.10 v2] kvm: Print MSR information if KVM_{GET, SET}_MSRS failed
@ 2017-03-09 19:46 Eduardo Habkost
2017-03-09 20:08 ` Dr. David Alan Gilbert
0 siblings, 1 reply; 4+ messages in thread
From: Eduardo Habkost @ 2017-03-09 19:46 UTC (permalink / raw)
To: qemu-devel, Paolo Bonzini; +Cc: Dr. David Alan Gilbert
When a KVM_{GET,SET}_MSRS ioctl() fails, it is difficult to find
out which MSR caused the problem. Print an error message for
debugging, before we trigger the (ret == cpu->kvm_msr_buf->nmsrs)
assert.
Suggested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
Changes v1 -> v2:
* Print error message on KVM_GET_MSRS too
* Suggested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
target/i386/kvm.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index 887a81268f..705e971a63 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -1807,6 +1807,12 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
return ret;
}
+ if (ret < cpu->kvm_msr_buf->nmsrs) {
+ struct kvm_msr_entry *e = &cpu->kvm_msr_buf->entries[ret];
+ error_report("error: failed to set MSR 0x%" PRIx32 " to 0x%" PRIx64,
+ (uint32_t)e->index, (uint64_t)e->data);
+ }
+
assert(ret == cpu->kvm_msr_buf->nmsrs);
return 0;
}
@@ -2172,6 +2178,12 @@ static int kvm_get_msrs(X86CPU *cpu)
return ret;
}
+ if (ret < cpu->kvm_msr_buf->nmsrs) {
+ struct kvm_msr_entry *e = &cpu->kvm_msr_buf->entries[ret];
+ error_report("error: failed to get MSR 0x%" PRIx32,
+ (uint32_t)e->index);
+ }
+
assert(ret == cpu->kvm_msr_buf->nmsrs);
/*
* MTRR masks: Each mask consists of 5 parts
--
2.11.0.259.g40922b1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH for-2.10 v2] kvm: Print MSR information if KVM_{GET, SET}_MSRS failed
2017-03-09 19:46 [Qemu-devel] [PATCH for-2.10 v2] kvm: Print MSR information if KVM_{GET, SET}_MSRS failed Eduardo Habkost
@ 2017-03-09 20:08 ` Dr. David Alan Gilbert
2017-03-09 20:26 ` [Qemu-devel] [PATCH for-2.9? " Eduardo Habkost
0 siblings, 1 reply; 4+ messages in thread
From: Dr. David Alan Gilbert @ 2017-03-09 20:08 UTC (permalink / raw)
To: Eduardo Habkost; +Cc: qemu-devel, Paolo Bonzini
* Eduardo Habkost (ehabkost@redhat.com) wrote:
> When a KVM_{GET,SET}_MSRS ioctl() fails, it is difficult to find
> out which MSR caused the problem. Print an error message for
> debugging, before we trigger the (ret == cpu->kvm_msr_buf->nmsrs)
> assert.
>
> Suggested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Thanks!
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
I'd actually suggest it for 2.9; it's only added debug output.
Dave
> ---
> Changes v1 -> v2:
> * Print error message on KVM_GET_MSRS too
> * Suggested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
> target/i386/kvm.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> index 887a81268f..705e971a63 100644
> --- a/target/i386/kvm.c
> +++ b/target/i386/kvm.c
> @@ -1807,6 +1807,12 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
> return ret;
> }
>
> + if (ret < cpu->kvm_msr_buf->nmsrs) {
> + struct kvm_msr_entry *e = &cpu->kvm_msr_buf->entries[ret];
> + error_report("error: failed to set MSR 0x%" PRIx32 " to 0x%" PRIx64,
> + (uint32_t)e->index, (uint64_t)e->data);
> + }
> +
> assert(ret == cpu->kvm_msr_buf->nmsrs);
> return 0;
> }
> @@ -2172,6 +2178,12 @@ static int kvm_get_msrs(X86CPU *cpu)
> return ret;
> }
>
> + if (ret < cpu->kvm_msr_buf->nmsrs) {
> + struct kvm_msr_entry *e = &cpu->kvm_msr_buf->entries[ret];
> + error_report("error: failed to get MSR 0x%" PRIx32,
> + (uint32_t)e->index);
> + }
> +
> assert(ret == cpu->kvm_msr_buf->nmsrs);
> /*
> * MTRR masks: Each mask consists of 5 parts
> --
> 2.11.0.259.g40922b1
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH for-2.9? v2] kvm: Print MSR information if KVM_{GET, SET}_MSRS failed
2017-03-09 20:08 ` Dr. David Alan Gilbert
@ 2017-03-09 20:26 ` Eduardo Habkost
2017-03-10 8:29 ` Paolo Bonzini
0 siblings, 1 reply; 4+ messages in thread
From: Eduardo Habkost @ 2017-03-09 20:26 UTC (permalink / raw)
To: Dr. David Alan Gilbert; +Cc: qemu-devel, Paolo Bonzini
On Thu, Mar 09, 2017 at 08:08:00PM +0000, Dr. David Alan Gilbert wrote:
> * Eduardo Habkost (ehabkost@redhat.com) wrote:
> > When a KVM_{GET,SET}_MSRS ioctl() fails, it is difficult to find
> > out which MSR caused the problem. Print an error message for
> > debugging, before we trigger the (ret == cpu->kvm_msr_buf->nmsrs)
> > assert.
> >
> > Suggested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
>
> Thanks!
>
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
>
> I'd actually suggest it for 2.9; it's only added debug output.
I think I agree. The patch is reasonably safe because we would be
already hitting the assert() if (ret < cpu->kvm_msr_buf->nmsrs)
anyway.
Paolo, do you want to queue it for 2.9?
>
> Dave
>
> > ---
> > Changes v1 -> v2:
> > * Print error message on KVM_GET_MSRS too
> > * Suggested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> > ---
> > target/i386/kvm.c | 12 ++++++++++++
> > 1 file changed, 12 insertions(+)
> >
> > diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> > index 887a81268f..705e971a63 100644
> > --- a/target/i386/kvm.c
> > +++ b/target/i386/kvm.c
> > @@ -1807,6 +1807,12 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
> > return ret;
> > }
> >
> > + if (ret < cpu->kvm_msr_buf->nmsrs) {
> > + struct kvm_msr_entry *e = &cpu->kvm_msr_buf->entries[ret];
> > + error_report("error: failed to set MSR 0x%" PRIx32 " to 0x%" PRIx64,
> > + (uint32_t)e->index, (uint64_t)e->data);
> > + }
> > +
> > assert(ret == cpu->kvm_msr_buf->nmsrs);
> > return 0;
> > }
> > @@ -2172,6 +2178,12 @@ static int kvm_get_msrs(X86CPU *cpu)
> > return ret;
> > }
> >
> > + if (ret < cpu->kvm_msr_buf->nmsrs) {
> > + struct kvm_msr_entry *e = &cpu->kvm_msr_buf->entries[ret];
> > + error_report("error: failed to get MSR 0x%" PRIx32,
> > + (uint32_t)e->index);
> > + }
> > +
> > assert(ret == cpu->kvm_msr_buf->nmsrs);
> > /*
> > * MTRR masks: Each mask consists of 5 parts
> > --
> > 2.11.0.259.g40922b1
> >
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
--
Eduardo
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH for-2.9? v2] kvm: Print MSR information if KVM_{GET, SET}_MSRS failed
2017-03-09 20:26 ` [Qemu-devel] [PATCH for-2.9? " Eduardo Habkost
@ 2017-03-10 8:29 ` Paolo Bonzini
0 siblings, 0 replies; 4+ messages in thread
From: Paolo Bonzini @ 2017-03-10 8:29 UTC (permalink / raw)
To: Eduardo Habkost, Dr. David Alan Gilbert; +Cc: qemu-devel
On 09/03/2017 21:26, Eduardo Habkost wrote:
> On Thu, Mar 09, 2017 at 08:08:00PM +0000, Dr. David Alan Gilbert wrote:
>> * Eduardo Habkost (ehabkost@redhat.com) wrote:
>>> When a KVM_{GET,SET}_MSRS ioctl() fails, it is difficult to find
>>> out which MSR caused the problem. Print an error message for
>>> debugging, before we trigger the (ret == cpu->kvm_msr_buf->nmsrs)
>>> assert.
>>>
>>> Suggested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
>>> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
>>
>> Thanks!
>>
>> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
>>
>> I'd actually suggest it for 2.9; it's only added debug output.
>
> I think I agree. The patch is reasonably safe because we would be
> already hitting the assert() if (ret < cpu->kvm_msr_buf->nmsrs)
> anyway.
>
> Paolo, do you want to queue it for 2.9?
Yes, with pleasure.
Paolo
>>
>> Dave
>>
>>> ---
>>> Changes v1 -> v2:
>>> * Print error message on KVM_GET_MSRS too
>>> * Suggested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
>>> ---
>>> target/i386/kvm.c | 12 ++++++++++++
>>> 1 file changed, 12 insertions(+)
>>>
>>> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
>>> index 887a81268f..705e971a63 100644
>>> --- a/target/i386/kvm.c
>>> +++ b/target/i386/kvm.c
>>> @@ -1807,6 +1807,12 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
>>> return ret;
>>> }
>>>
>>> + if (ret < cpu->kvm_msr_buf->nmsrs) {
>>> + struct kvm_msr_entry *e = &cpu->kvm_msr_buf->entries[ret];
>>> + error_report("error: failed to set MSR 0x%" PRIx32 " to 0x%" PRIx64,
>>> + (uint32_t)e->index, (uint64_t)e->data);
>>> + }
>>> +
>>> assert(ret == cpu->kvm_msr_buf->nmsrs);
>>> return 0;
>>> }
>>> @@ -2172,6 +2178,12 @@ static int kvm_get_msrs(X86CPU *cpu)
>>> return ret;
>>> }
>>>
>>> + if (ret < cpu->kvm_msr_buf->nmsrs) {
>>> + struct kvm_msr_entry *e = &cpu->kvm_msr_buf->entries[ret];
>>> + error_report("error: failed to get MSR 0x%" PRIx32,
>>> + (uint32_t)e->index);
>>> + }
>>> +
>>> assert(ret == cpu->kvm_msr_buf->nmsrs);
>>> /*
>>> * MTRR masks: Each mask consists of 5 parts
>>> --
>>> 2.11.0.259.g40922b1
>>>
>> --
>> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2017-03-09 19:46 [Qemu-devel] [PATCH for-2.10 v2] kvm: Print MSR information if KVM_{GET, SET}_MSRS failed Eduardo Habkost
2017-03-09 20:08 ` Dr. David Alan Gilbert
2017-03-09 20:26 ` [Qemu-devel] [PATCH for-2.9? " Eduardo Habkost
2017-03-10 8:29 ` Paolo Bonzini
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