Re: [Qemu-devel] r6677 broke access to physical FDD on Win32

[Anthony Liguori]

Luca Tettamanti wrote:
> On Fri, Mar 20, 2009 at 11:01 PM, Anthony Liguori <address@hidden> wrote:
>   
> > Robert Riebisch wrote:
> >     
> > > Hi!
> > >
> > > If I run QEMU on Win32 with option "-fda a:", then I'm unable to access
> > > physical floppies from guest OS. "Physical" also includes virtual drives
> > > created by <http://chitchat.at.infoseek.co.jp/vmware/vfd.html>.
> > >
> > > I'm also unable to boot such floppies ("-boot a"). Error message is:
> > > "Boot failed: not a bootable floppy disk"
> > >
> > > By doing some builds I narrowed the problem down to
> > > <http://svn.savannah.gnu.org/viewvc?view=rev&root=qemu&revision=6677> by
> > > Anthony Liguori.
> > >
> > >       
> > I suspect this code:
> >
> > block-raw-win32.c:raw_getlength():
> >
> >   case FTYPE_HARDDISK:
> >       status = DeviceIoControl(s->hfile, IOCTL_DISK_GET_DRIVE_GEOMETRY_EX,
> >                                NULL, 0, &dg, sizeof(dg), &count, NULL);
> >       if (status != 0) {
> >           l = dg.DiskSize;
> >       }
> >       break;
> >
> > Is not doing the correct thing.
> >     
>
> Sort of; the real problem is in find_device_type(), it thinks that the
> device is a file :S
>
> The bug is here:
>   type = GetDriveType(s->drive_path);
>   if (type == DRIVE_CDROM)
>     return FTYPE_CD;
>   else
>     return FTYPE_FILE;
>
> GetDriveType("a:") returns DRIVE_REMOVABLE, which according to MSDN
> means "The drive has removable media; for example, a floppy drive,
> thumb drive, or flash card reader."; the code is not expecting such a
> value so it sets the type to FTYPE_FILE; raw_getlength() then uses
> GetFileSize() which of course fails...
>
> Here's a patch for properly handling the return value of GetDriveType
> (sorry for the attachment, but I'm currently using a remote VM over
> RDP and don't have a decent mailer installed).
>
> Luca
>   
Applied.  Thanks.

--
Regards,

Anthony Liguori