>>> On 05.09.16 at 19:20, <george.dun...@citrix.com> wrote: > On 05/09/16 14:31, Jan Beulich wrote: >>>>> On 02.09.16 at 12:47, <yu.c.zh...@linux.intel.com> wrote: >>> @@ -178,8 +179,27 @@ static int hvmemul_do_io( >>> break; >>> case X86EMUL_UNHANDLEABLE: >>> { >>> - struct hvm_ioreq_server *s = >>> - hvm_select_ioreq_server(curr->domain, &p); >>> + struct hvm_ioreq_server *s = NULL; >>> + p2m_type_t p2mt = p2m_invalid; >>> + >>> + if ( is_mmio ) >>> + { >>> + unsigned long gmfn = paddr_to_pfn(addr); >>> + >>> + (void) get_gfn_query_unlocked(currd, gmfn, &p2mt); >>> + >>> + if ( p2mt == p2m_ioreq_server && dir == IOREQ_WRITE ) >>> + { >>> + unsigned int flags; >>> + >>> + s = p2m_get_ioreq_server(currd, &flags); >>> + if ( !(flags & XEN_HVMOP_IOREQ_MEM_ACCESS_WRITE) ) >>> + s = NULL; >>> + } >>> + } >>> + >>> + if ( !s && p2mt != p2m_ioreq_server ) >>> + s = hvm_select_ioreq_server(currd, &p); >> >> What I recall is that we had agreed on p2m_ioreq_server pages >> to be treated as ordinary RAM ones as long as no server can be >> found. The type check here contradicts that. Is there a reason? > > I think it must be a confusion as to what "treated like ordinary RAM > ones" means. p2m_ram_rw types that gets here will go through > hvm_select_ioreq_server(), and (therefore) potentially be treated as > MMIO accesses, which is not how "ordinary RAM" would behave. If what > you meant was that you want p2m_ioreq_server to behave like p2m_ram_rw > (and be treated as MMIO if it matches an iorange) then yes. If what you > want is for p2m_ioreq_server to actually act like RAM, then probably > something more needs to happen here.
Well, all I'm questioning is the special casing of p2m_ioreq_server in the if(). That's imo orthogonal to p2m_ram_rw pages not being supposed to make it here (hence the is_mmio check in the earlier if() also looks questionable). Perhaps it would already help if there was a comment explaining what the exact intended behavior here is. Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel