> -----Original Message----- > From: Wei Liu [mailto:wei.l...@citrix.com] > Sent: 28 August 2017 16:01 > To: Paul Durrant <paul.durr...@citrix.com> > Cc: xen-de...@lists.xenproject.org; George Dunlap > <george.dun...@citrix.com>; Andrew Cooper > <andrew.coop...@citrix.com>; Jan Beulich <jbeul...@suse.com>; Wei Liu > <wei.l...@citrix.com> > Subject: Re: [Xen-devel] [PATCH v2 REPOST 03/12] x86/mm: add > HYPERVISOR_memory_op to acquire guest resources > > On Tue, Aug 22, 2017 at 03:50:57PM +0100, Paul Durrant wrote: > > + > > +/* > > + * Get the pages for a particular guest resource, so that they can be > > + * mapped directly by a tools domain. > > + */ > > +#define XENMEM_acquire_resource 28 > > +struct xen_mem_acquire_resource { > > + /* IN - the domain whose resource is to be mapped */ > > + domid_t domid; > > + /* IN - the type of resource (defined below) */ > > + uint16_t type; > > + > > +#define XENMEM_resource_grant_table 0 > > + > > + /* > > + * IN - a type-specific resource identifier, which must be zero > > + * unless stated otherwise. > > + */ > > + uint32_t id; > > + /* IN - number of (4K) frames of the resource to be mapped */ > > + uint32_t nr_frames; > > + /* IN - the index of the initial frame to be mapped */ > > + uint64_aligned_t frame; > > + /* IN/OUT - If the tools domain is PV then, upon return, gmfn_list > > + * will be populated with the MFNs of the resource. > > + * If the tools domain is HVM then it is expected that, on > > + * entry, gmfn_list will be populated with a list of GFNs > > + * that will be mapped to the MFNs of the resource. > > + */ > > + XEN_GUEST_HANDLE(xen_pfn_t) gmfn_list; > > Why is it not possible to make PV does the same thing as HVM?
Because PV guests don't use a P2M as such. An HVM guest can pass GFNs in and say 'I want the resource mapped here'. A PV guest can't do that since it's using MFNs directly... it has to deal with the resource wherever it may be. Paul _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
