I am trying to find out the max pgfn for a 256MB PV guest. If I call xc_domain_getinfolist() and look at xc_domaininfo->max_pages, I get 0x10100. If I call xc_domain_getinfo() and look at xc_dominfo->nr_pages, I get 0x10000. Within the hypervisor if I call domain_get_maximum_gpfn(), I get 0xffff. So it looks like xc_domain_getinfo() is returning the correct value. Why is xc_domain_getinfolist() returning a different value? Which value should I be looking at for the max gpfn? Thanks, Aravindh _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
>>> On 08.11.13 at 21:58, "Aravindh Puthiyaparambil (aravindp)"<aravindp@cisco.com> wrote:> I am trying to find out the max pgfn for a 256MB PV guest. If I call > xc_domain_getinfolist() and look at xc_domaininfo->max_pages, I get 0x10100. If > I call xc_domain_getinfo() and look at xc_dominfo->nr_pages, I get 0x10000. > Within the hypervisor if I call domain_get_maximum_gpfn(), I get 0xffff. So > it looks like xc_domain_getinfo() is returning the correct value. Why is > xc_domain_getinfolist() returning a different value? Which value should I be > looking at for the max gpfn?I''m afraid none of these - since PV guests control the P2M mapping themselves, there simply is no "max GPFN" being tracked here. (The value returned by domain_get_maximum_gpfn() originates from the shared info structure, i.e. again is only valid if the guest cares to maintain that field.) Jan
>>>> On 08.11.13 at 21:58, "Aravindh Puthiyaparambil (aravindp)" ><aravindp@cisco.com> wrote: >> I am trying to find out the max pgfn for a 256MB PV guest. If I call >> xc_domain_getinfolist() and look at xc_domaininfo->max_pages, I get >> 0x10100. If I call xc_domain_getinfo() and look at xc_dominfo->nr_pages, I >get 0x10000. >> Within the hypervisor if I call domain_get_maximum_gpfn(), I get >> 0xffff. So it looks like xc_domain_getinfo() is returning the correct >> value. Why is >> xc_domain_getinfolist() returning a different value? Which value >> should I be looking at for the max gpfn? > >I''m afraid none of these - since PV guests control the P2M mapping >themselves, there simply is no "max GPFN" being tracked here. (The value >returned by domain_get_maximum_gpfn() originates from the shared info >structure, i.e. again is only valid if the guest cares to maintain that field.)Does this also hold true for PV guests running with shadow page tables? Thanks, Aravindh
>>> On 11.11.13 at 17:42, "Aravindh Puthiyaparambil (aravindp)"<aravindp@cisco.com> wrote:>>>>> On 08.11.13 at 21:58, "Aravindh Puthiyaparambil (aravindp)" >><aravindp@cisco.com> wrote: >>> I am trying to find out the max pgfn for a 256MB PV guest. If I call >>> xc_domain_getinfolist() and look at xc_domaininfo->max_pages, I get >>> 0x10100. If I call xc_domain_getinfo() and look at xc_dominfo->nr_pages, I >>get 0x10000. >>> Within the hypervisor if I call domain_get_maximum_gpfn(), I get >>> 0xffff. So it looks like xc_domain_getinfo() is returning the correct >>> value. Why is >>> xc_domain_getinfolist() returning a different value? Which value >>> should I be looking at for the max gpfn? >> >>I''m afraid none of these - since PV guests control the P2M mapping >>themselves, there simply is no "max GPFN" being tracked here. (The value >>returned by domain_get_maximum_gpfn() originates from the shared info >>structure, i.e. again is only valid if the guest cares to maintain that > field.) > > Does this also hold true for PV guests running with shadow page tables?I would think so, but I don''t know enough about this mode to be certain. Jan
At 16:47 +0000 on 11 Nov (1384184876), Jan Beulich wrote:> >>> On 11.11.13 at 17:42, "Aravindh Puthiyaparambil (aravindp)" > <aravindp@cisco.com> wrote: > >>>>> On 08.11.13 at 21:58, "Aravindh Puthiyaparambil (aravindp)" > >><aravindp@cisco.com> wrote: > >>> I am trying to find out the max pgfn for a 256MB PV guest. If I call > >>> xc_domain_getinfolist() and look at xc_domaininfo->max_pages, I get > >>> 0x10100. If I call xc_domain_getinfo() and look at xc_dominfo->nr_pages, I > >>get 0x10000. > >>> Within the hypervisor if I call domain_get_maximum_gpfn(), I get > >>> 0xffff. So it looks like xc_domain_getinfo() is returning the correct > >>> value. Why is > >>> xc_domain_getinfolist() returning a different value? Which value > >>> should I be looking at for the max gpfn? > >> > >>I''m afraid none of these - since PV guests control the P2M mapping > >>themselves, there simply is no "max GPFN" being tracked here. (The value > >>returned by domain_get_maximum_gpfn() originates from the shared info > >>structure, i.e. again is only valid if the guest cares to maintain that > > field.) > > > > Does this also hold true for PV guests running with shadow page tables? > > I would think so, but I don''t know enough about this mode to be > certain.Yes; PV guests under shadow pagetables still control their own memory layout. Tim.