On 14/01/16 09:12, Jan Beulich wrote: >>>> On 14.01.16 at 09:35, <roger....@citrix.com> wrote: >> El 13/01/16 a les 17.48, Paul Durrant ha escrit: >>>> -----Original Message----- >>>> From: Jan Beulich [mailto:jbeul...@suse.com] >>>> Sent: 13 January 2016 16:39 >>>> To: Paul Durrant; Roger Pau Monne >>>> Cc: Andrew Cooper; xen-de...@lists.xenproject.org >>>> Subject: Re: [PATCH 5/5] x86/HVM: don't setup an intercept handler for IO >>>> port 0xcf8 unconditionally >>>> >>>>>>> On 13.01.16 at 13:32, <roger....@citrix.com> wrote: >>>>> Only intercept accesses to IO port 0xcf8 if there's at least one IOREQ >>>>> server, otherwise it makes no sense since the only code that uses the >>>>> value >>>>> stored by hvm_access_cf8 is the IOREQ server. >>>> Afaict an ioreq server could also attach subsequently - Paul? >>>> >>> Indeed, ioreq servers can come and go at any time. >> Right, then I will have to prevent hvm_access_cf8 from being added if >> the domain is the hardware domain, otherwise it overlaps with the Dom0 >> passthrough intercept (handle_pvh_io). > Yes, that indeed makes sense.
Even for the hardware domain, cf8 needs trapping and emulating (although on a different path). Being an indirect port pair shared by Xen and dom0, dom0 cannot use it directly of its own accord. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
