> -----Original Message----- > From: xen-devel-boun...@lists.xen.org [mailto:xen-devel- > boun...@lists.xen.org] On Behalf Of Andrew Cooper > Sent: 14 October 2015 17:02 > To: Jan Beulich; Roger Pau Monne > Cc: xen-de...@lists.xenproject.org > Subject: Re: [Xen-devel] [PATCH v7 23/32] xen/x86: make sure the HVM > callback vector is correctly set > > On 14/10/15 16:54, Jan Beulich wrote: > >>>> On 02.10.15 at 17:48, <roger....@citrix.com> wrote: > >> --- a/xen/arch/x86/hvm/irq.c > >> +++ b/xen/arch/x86/hvm/irq.c > >> @@ -330,6 +330,10 @@ void hvm_set_callback_via(struct domain *d, > uint64_t > >> via) > >> (via_type > HVMIRQ_callback_vector) ) > >> via_type = HVMIRQ_callback_none; > >> > >> + if ( via_type != HVMIRQ_callback_vector && > >> + (!has_vlapic(d) || !has_vioapic(d) || !has_vpic(d)) ) > >> + return; > > Why are both IO-APIC and PIC required? Doesn't one suffice, or > > can't MSI-like interrupts even get delivered without either? > > In real hardware, MSI-like interrupts have no interaction with the > IO-APIC or PIC. > > In fact, the purpose of the IO-APIC is to turn legacy line interrupts > into MSI interrupts. The PICs were from the pre-MSI days where it > asserted the #INTR pin on the processor. > > Our virtual interrupt infrastructure should behave in a consistent manor. >
IIRC both the intx and gsi variants of the callback via go in at the vioapic level. Paul > ~Andrew > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
