On 06/09/18 10:16, Paul Durrant wrote: >> -----Original Message----- >> From: Andrew Cooper [mailto:andrew.coop...@citrix.com] >> Sent: 05 September 2018 19:12 >> To: Xen-devel <xen-de...@lists.xen.org> >> Cc: Andrew Cooper <andrew.coop...@citrix.com>; Jan Beulich >> <jbeul...@suse.com>; Wei Liu <wei.l...@citrix.com>; Roger Pau Monne >> <roger....@citrix.com>; Paul Durrant <paul.durr...@citrix.com>; Stefano >> Stabellini <sstabell...@kernel.org>; Julien Grall <julien.gr...@arm.com> >> Subject: [PATCH 3/5] x86/hvm: Make >> HVM_PARAM_{STORE,CONSOLE}_EVTCHN read-only to the guest >> >> These values are set by the toolstack for each create/restore operation, and >> bound by xen{store,console}d before the the guest starts running. >> >> A guest has no reason to modify them at all, and the matching *_PFN >> parameters >> are already read-only. Adjust the *_EVTCHN permissions to be consistent. > Unfortunately this patch will break the Windows PV driver function here: > > http://xenbits.xen.org/gitweb/?p=pvdrivers/win/xenbus.git;a=blob;f=src/xenbus/evtchn.c;hb=HEAD#l1037 > > Unfortunately the values really do change across a reset. It would be > possible to use volatile (disappear on reboot) registry keys to store the > updated values instead but I don't really see any harm in allowing the guest > to update the values to be correct, unless we want to change Xen to do the > job so the guest doesn't have to go through this dance.
:( Everything is terrible. This is a general problem, not x86 specific, so I'll drop this patch and make a similar adjustment to the ARM one. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
