Re: [Qemu-devel] [PATCH for-2.10 v2] kvm: Print MSR information if KVM_{GET, SET}_MSRS failed

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* 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