| Message ID | 20170309194634.28457-1-ehabkost@redhat.com |
|---|---|
| State | New |
| Headers | show |
* 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
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
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 >
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
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(+)