[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 5/5] x86/HVM: don't setup an intercept handler for IO port 0xcf8 unconditionally
El 14/01/16 a les 11.50, Andrew Cooper ha escrit: > On 14/01/16 09:12, Jan Beulich wrote: >>>>> On 14.01.16 at 09:35, <roger.pau@xxxxxxxxxx> wrote: >>> El 13/01/16 a les 17.48, Paul Durrant ha escrit: >>>>> -----Original Message----- >>>>> From: Jan Beulich [mailto:JBeulich@xxxxxxxx] >>>>> Sent: 13 January 2016 16:39 >>>>> To: Paul Durrant; Roger Pau Monne >>>>> Cc: Andrew Cooper; xen-devel@xxxxxxxxxxxxxxxxxxxx >>>>> 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.pau@xxxxxxxxxx> 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. Sure, but it has to be handled by handle_pvh_io (which I plan to rename in due time) and not hvm_access_cf8. Roger. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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