Folks -- I''m porting FreeBSD to support PAE on xen-unstable. (Is anybody else doing this?) The kernel image I have properly communicates to Xend that the kernel is PAE aware and supports [extended-cr3] semantics (which I now fully understand; thanks Keir!). My kernel gets loaded into guest memory and I attach gdbserver-xen to it. So far so good. I can view registers, I can step, I can look at global and local registers. All is good. But, if I attempt to modify memory, e.g., setting a break point, XEN coughs up an error: (XEN) DOM0: (file=mm.c, line=1750) Bad type (saw 2e000001 != exp e0000000) for mfn fa693 (pfn 572) (XEN) DOM0: (file=mm.c, line=618) Error getting mfn fa693 (pfn 572) from L1 entry 00000000fa693027 for dom7 Is anybody doing this? Or, am I out here alone ... again? Xen version 3.0-unstable (root@lab.netapp.com) (gcc version 4.0.3 (Ubuntu 4.0.3-1ubuntu5)) Mon Aug 28 17:24:36 PDT 2006 Latest ChangeSet: Thu Aug 24 01:49:41 2006 +0100 11249:1ff4cc298bec (I''m going to update my hg repository, but I still have the question about anybody else using gdbserver w/ PAE guests.) -- Randy _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
You want to talk to Kip Macy; I''ve done a little bit with freebsd7 domus, (essentially, I have hacked makefiles to make Kip Macy''s stuff compile with -current of a few weeks ago instead of -current of a few months ago) but I am lacking in both skill and time, so I probably can not help you much. I don''t know of anyone working with FreeBSD on Xen PAE, though. On Wed, 4 Oct 2006, Randy Thelen wrote:> Date: Wed, 4 Oct 2006 16:53:39 -0700 > From: Randy Thelen <rthelen@netapp.com> > To: xen-devel <xen-devel@lists.xensource.com> > Subject: [Xen-devel] Anybody debugging PAE guest kernels? > > Folks -- > > I''m porting FreeBSD to support PAE on xen-unstable. (Is anybody else doing > this?) The kernel image I have properly communicates to Xend that the kernel > is PAE aware and supports [extended-cr3] semantics (which I now fully > understand; thanks Keir!). > > My kernel gets loaded into guest memory and I attach gdbserver-xen to it. So > far so good. I can view registers, I can step, I can look at global and > local registers. All is good. > > But, if I attempt to modify memory, e.g., setting a break point, XEN coughs > up an error: > > (XEN) DOM0: (file=mm.c, line=1750) Bad type (saw 2e000001 != exp e0000000) > for mfn fa693 (pfn 572) > (XEN) DOM0: (file=mm.c, line=618) Error getting mfn fa693 (pfn 572) from L1 > entry 00000000fa693027 for dom7 > > Is anybody doing this? Or, am I out here alone ... again? > > Xen version 3.0-unstable (root@lab.netapp.com) (gcc version 4.0.3 (Ubuntu > 4.0.3-1ubuntu5)) Mon Aug 28 17:24:36 PDT 2006 > Latest ChangeSet: Thu Aug 24 01:49:41 2006 +0100 11249:1ff4cc298bec > > (I''m going to update my hg repository, but I still have the question about > anybody else using gdbserver w/ PAE guests.) > > -- Randy > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Randy''s probably a little fed up - I don''t think I responded to his last e-mail :-/. Not out of spite, but rather overwhelmed with other things going on. Anyhow, the function to look at is map_domain_va_pae in tools/libxc/xc_ptrace.c. The checks for HVM support seem to not always happen correctly. HTH. -Kip On Wed, 4 Oct 2006, Luke Crawford wrote:> > You want to talk to Kip Macy; I''ve done a little bit with > freebsd7 domus, (essentially, I have hacked makefiles to make Kip Macy''s > stuff compile with -current of a few weeks ago instead of -current of a > few months ago) but I am lacking in both skill and time, so I probably > can not help you much. > > I don''t know of anyone working with FreeBSD on Xen PAE, though. > > On Wed, 4 Oct 2006, Randy Thelen wrote: > > > Date: Wed, 4 Oct 2006 16:53:39 -0700 > > From: Randy Thelen <rthelen@netapp.com> > > To: xen-devel <xen-devel@lists.xensource.com> > > Subject: [Xen-devel] Anybody debugging PAE guest kernels? > > > > Folks -- > > > > I''m porting FreeBSD to support PAE on xen-unstable. (Is anybody else doing > > this?) The kernel image I have properly communicates to Xend that the kernel > > is PAE aware and supports [extended-cr3] semantics (which I now fully > > understand; thanks Keir!). > > > > My kernel gets loaded into guest memory and I attach gdbserver-xen to it. So > > far so good. I can view registers, I can step, I can look at global and > > local registers. All is good. > > > > But, if I attempt to modify memory, e.g., setting a break point, XEN coughs > > up an error: > > > > (XEN) DOM0: (file=mm.c, line=1750) Bad type (saw 2e000001 != exp e0000000) > > for mfn fa693 (pfn 572) > > (XEN) DOM0: (file=mm.c, line=618) Error getting mfn fa693 (pfn 572) from L1 > > entry 00000000fa693027 for dom7 > > > > Is anybody doing this? Or, am I out here alone ... again? > > > > Xen version 3.0-unstable (root@lab.netapp.com) (gcc version 4.0.3 (Ubuntu > > 4.0.3-1ubuntu5)) Mon Aug 28 17:24:36 PDT 2006 > > Latest ChangeSet: Thu Aug 24 01:49:41 2006 +0100 11249:1ff4cc298bec > > > > (I''m going to update my hg repository, but I still have the question about > > anybody else using gdbserver w/ PAE guests.) > > > > -- Randy > > > > _______________________________________________ > > Xen-devel mailing list > > Xen-devel@lists.xensource.com > > http://lists.xensource.com/xen-devel > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel >_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Kip Macy wrote:> Randy''s probably a little fed up - I don''t think I responded to his > last > e-mail :-/. Not out of spite, but rather overwhelmed with other things > going on.:-) No worries.> Anyhow, the function to look at is map_domain_va_pae in > tools/libxc/xc_ptrace.c. The checks for HVM support seem to not always > happen correctly. HTH.Thanks for the tip. However, note that I''m not running HVM and the error I''m getting comes from Xen proper:>> (XEN) DOM0: (file=mm.c, line=1750) Bad type (saw 2e000001 != exp >> e0000000) >> for mfn fa693 (pfn 572) >> (XEN) DOM0: (file=mm.c, line=618) Error getting mfn fa693 (pfn >> 572) from L1 >> entry 00000000fa693027 for dom7-- Randy _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
> > Anyhow, the function to look at is map_domain_va_pae in > > tools/libxc/xc_ptrace.c. The checks for HVM support seem to not always > > happen correctly. HTH. > > Thanks for the tip. However, note that I''m not running HVM and the > error I''m getting comes from Xen proper:Exactly. I''ve seen cases where the HVM check returns true when running against a paravirtualized FreeBSD guest. I had my mentee ifdef out the HVM check in his local copy of gdbserver. In your case, if the code is not parsing the page tables correctly it can result in in trying to read / write memory it isn''t allowed to. Tracing errors back from mm.c is always a monumental PITA, but it might be worth looking at. At the very least, check what type it expects the page to be - I''ve long since forgotten what the numbers correspond to. If you''re not already familiar with the page typing code you should have a look, familiarity with it will make tracking down errors much easier. One last thing to bear in mind for future reference is that DOM0 can''t map page tables, even for a domU (at least last I tried), read/write. -Kip> > >> (XEN) DOM0: (file=mm.c, line=1750) Bad type (saw 2e000001 != exp > >> e0000000) > >> for mfn fa693 (pfn 572) > >> (XEN) DOM0: (file=mm.c, line=618) Error getting mfn fa693 (pfn > >> 572) from L1 > >> entry 00000000fa693027 for dom7 > > -- Randy > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel >_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel