RE: [PATCH 3/6] Delete stornvme's StartOverride

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

> -----Original Message-----
> From: win-pv-devel <win-pv-devel-bounces@xxxxxxxxxxxxxxxxxxxx> On Behalf Of 
> Owen Smith
> Sent: 28 June 2021 14:51
> To: Owen Smith <owen.smith@xxxxxxxxxx>; paul@xxxxxxx; 
> win-pv-devel@xxxxxxxxxxxxxxxxxxxx
> Subject: RE: [EXTERNAL] [PATCH 3/6] Delete stornvme's StartOverride
> 
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> 
> 
> -----Original Message-----
> From: win-pv-devel <win-pv-devel-bounces@xxxxxxxxxxxxxxxxxxxx> On Behalf Of 
> Owen Smith
> Sent: Monday, June 21, 2021 4:33 PM
> To: paul@xxxxxxx; win-pv-devel@xxxxxxxxxxxxxxxxxxxx
> Subject: RE: [PATCH 3/6] Delete stornvme's StartOverride
> 
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> -----Original Message-----
> From: win-pv-devel <win-pv-devel-bounces@xxxxxxxxxxxxxxxxxxxx> On Behalf Of 
> Paul Durrant
> Sent: Monday, June 21, 2021 2:48 PM
> To: win-pv-devel@xxxxxxxxxxxxxxxxxxxx
> Subject: Re: [PATCH 3/6] Delete stornvme's StartOverride
> 
> [CAUTION - EXTERNAL EMAIL] DO NOT reply, click links, or open attachments 
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> On 17/06/2021 13:33, Owen Smith wrote:
> > Using an emulated NVMe device for installation will not be able to
> > revert to emulated NVMe device once xenvbd has been used to boot. This
> > is due to stornvme creating a StartOverride value that overrides
> > stornvme's StartType to manual (from boot) when stornvme is not loaded
> > during boot. This occurs when xenbus has unplugged the emulated NVMe
> > controller at boot. Disabling the unplug is not sufficient to have
> > stornvme load at boot, which results in a 0x7B bugcheck.
> 
> Ick!
> 
> >
> > Signed-off-by: Owen Smith <owen.smith@xxxxxxxxxx>
> > ---
> >   src/monitor/monitor.c | 60 +++++++++++++++++++++++++++++++++++++++++++
> >   1 file changed, 60 insertions(+)
> >
> > diff --git a/src/monitor/monitor.c b/src/monitor/monitor.c
> 
> Not sure the monitor is the best place to do this; it seems a little too 
> critical for that. Could we
> use this ancient interface instead?
> 
> https://docs.microsoft.com/en-us/windows-hardware/drivers/ddi/ntddk/nf-ntddk-
> ioregisterbootdriverreinitialization
> 
>    Paul
> 
> 
> This looks doable, calling IoRegisterBootDriverReinitialization from XenVbd's 
> DriverEntry and clearing
> the StartOverride from the reinitialize routine
> 
> Owen
> 
> 
> After some investigation, the IoRegisterBootDriverReinitialization callback 
> occurs too early and
> StorNvme adds the value later. It should only be required to ensure this 
> value is removed before the
> VM is shutdown or rebooted, so its possible that removing the StartOverride 
> in the unload/power down
> code would be appropriate.

Or could this even be done in xenvbd's co-installer?

  Paul

> 
> Owen
> 
> 
> > index 9adfb79..c858249 100644
> > --- a/src/monitor/monitor.c
> > +++ b/src/monitor/monitor.c
> > @@ -1172,6 +1172,64 @@ fail1:
> >       return FALSE;
> >   }
> >
> > +static BOOL
> > +DeleteStartOverride(
> > +    _In_    LPTSTR      DriverName
> > +    )
> > +{
> > +    TCHAR               ServiceKeyName[MAX_PATH];
> > +    HKEY                Key;
> > +    HRESULT             Error;
> > +
> > +    Error = StringCbPrintf(ServiceKeyName,
> > +                            MAX_PATH,
> > +                            SERVICES_KEY "\\%s",
> > +                            DriverName);
> > +    if (!SUCCEEDED(Error))
> > +        goto fail1;
> > +
> > +    Error = RegOpenKeyEx(HKEY_LOCAL_MACHINE,
> > +                         ServiceKeyName,
> > +                         0,
> > +                         KEY_ALL_ACCESS,
> > +                         &Key);
> > +    if (Error != ERROR_SUCCESS) {
> > +        SetLastError(Error);
> > +        goto fail2;
> > +    }
> > +
> > +    Error = RegDeleteTree(Key,
> > +                          "StartOverride");
> > +    if (Error != ERROR_SUCCESS) {
> > +        SetLastError(Error);
> > +        goto fail3;
> > +    }
> > +
> > +    RegCloseKey(Key);
> > +
> > +    return TRUE;
> > +
> > +fail3:
> > +    Log("fail3");
> > +
> > +    RegCloseKey(Key);
> > +
> > +fail2:
> > +    Log("fail2");
> > +
> > +fail1:
> > +    Error = GetLastError();
> > +
> > +    {
> > +        PTCHAR  Message;
> > +        Message = GetErrorMessage(Error);
> > +        Log("fail1 (%s)", Message);
> > +        LocalFree(Message);
> > +    }
> > +
> > +    return FALSE;
> > +}
> > +
> >   VOID WINAPI
> >   MonitorMain(
> >       _In_    DWORD       argc,
> > @@ -1251,6 +1309,7 @@ MonitorMain(
> >       if (!Success)
> >           goto fail9;
> >
> > +    (VOID) DeleteStartOverride("stornvme");
> >       SetEvent(Context->RequestEvent);
> >
> >       ReportStatus(SERVICE_RUNNING, NO_ERROR, 0); @@ -1285,6 +1344,7
> > @@ MonitorMain(
> >       }
> >
> >   done:
> > +    (VOID) DeleteStartOverride("stornvme");
> >       (VOID) RegDeleteTree(Context->RequestKey, NULL);
> >
> >       free(Context->Question);
> >
>