On Thu, Mar 09, 2017 at 08:08:00PM +0000, Dr. David Alan Gilbert wrote:
> * Eduardo Habkost (ehabk...@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 <dgilb...@redhat.com>
> > Signed-off-by: Eduardo Habkost <ehabk...@redhat.com>
>
> Thanks!
>
> Reviewed-by: Dr. David Alan Gilbert <dgilb...@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 <dgilb...@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 / dgilb...@redhat.com / Manchester, UK
--
Eduardo
