RE: [PATCH] Add log to Xenfilt DriverAddDevice

["Durrant, Paul" <pdurrant@xxxxxxxxxxxx>]

> -----Original Message-----
> From: win-pv-devel <win-pv-devel-bounces@xxxxxxxxxxxxxxxxxxxx> On Behalf Of 
> Owen Smith
> Sent: 13 July 2021 09:05
> To: paul@xxxxxxx; win-pv-devel@xxxxxxxxxxxxxxxxxxxx
> Subject: RE: [EXTERNAL] [PATCH] Add log to Xenfilt DriverAddDevice
> 
> CAUTION: This email originated from outside of the organization. Do not click 
> links or open
> attachments unless you can confirm the sender and know the content is safe.
> 
> 
> 
> -----Original Message-----
> From: win-pv-devel <win-pv-devel-bounces@xxxxxxxxxxxxxxxxxxxx> On Behalf Of 
> Paul Durrant
> Sent: Monday, July 12, 2021 8:06 PM
> To: win-pv-devel@xxxxxxxxxxxxxxxxxxxx
> Subject: Re: [PATCH] Add log to Xenfilt DriverAddDevice
> 
> [CAUTION - EXTERNAL EMAIL] DO NOT reply, click links, or open attachments 
> unless you have verified the
> sender and know the content is safe.
> 
> On 07/07/2021 09:54, Martin Harvey wrote:
> > From: Owen Smith <owen.smith@xxxxxxxxxx>
> >
> > Log all calls to DriverAddDevice, and the type of the device if
> > possible
> 
> Any particular reason existent logging is insufficient? I think we need more 
> justification here.
> 
>    Paul
> 
> 
> There have been cases where XenFilt loads on a device node that doesn’t match 
> a
> XENFILT_EMULATED_OBJECT_TYPE or DriverQueryId fails, and (on a release build) 
> nothing gets displayed.
> This is mostly debug output and may be excessive for standard use
> 

A DriverQueryId failure may well be worth a message if it is not a routine 
failure. Do you know how often it is seen in practice?

  Paul


> Owen
> 
> >
> > Signed-off-by: Owen Smith <owen.smith@xxxxxxxxxx>
> > ---
> >   src/xenfilt/driver.c | 17 +++++++++++++++++
> >   1 file changed, 17 insertions(+)
> >
> > diff --git a/src/xenfilt/driver.c b/src/xenfilt/driver.c index
> > 8f14ec8..2c9b54e 100644
> > --- a/src/xenfilt/driver.c
> > +++ b/src/xenfilt/driver.c
> > @@ -724,6 +724,19 @@ fail1:
> >       return status;
> >   }
> >
> > +static FORCEINLINE PCHAR
> > +__EmulatedTypeName(
> > +    IN  XENFILT_EMULATED_OBJECT_TYPE    Type
> > +    )
> > +{
> > +    switch (Type) {
> > +    case XENFILT_EMULATED_OBJECT_TYPE_UNKNOWN:  return "UNKNOWN";
> > +    case XENFILT_EMULATED_OBJECT_TYPE_PCI:      return "PCI";
> > +    case XENFILT_EMULATED_OBJECT_TYPE_IDE:      return "IDE";
> > +    default:                                    return "InvalidType";
> > +    }
> > +}
> > +
> >   static XENFILT_EMULATED_OBJECT_TYPE
> >   DriverGetEmulatedType(
> >       IN  PCHAR                       Id
> > @@ -805,6 +818,10 @@ DriverAddDevice(
> >           }
> >       }
> >
> > +    Info("%p %s\n",
> > +         PhysicalDeviceObject,
> > +         __EmulatedTypeName(Type));
> > +
> >       status = STATUS_SUCCESS;
> >       if (Type == XENFILT_EMULATED_OBJECT_TYPE_UNKNOWN)
> >           goto done;
> >
>