[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Cannot get shared page in domU
On Thu, Nov 10, 2011 at 10:54:23AM -0500, Xin Jin wrote: > In > > share_mem->gref = > gnttab_grant_foreign_access(domid_remote, virt_to_mfn(share_mem), 0); Huh? There are four parameters for that function. When you setup your map_op, are you setting GNTMAP_application_map | GNTMAP_contains_pte ? Or are using GNTMAP_host_map Did you look in the 3.1 linux kerne in the gntdev.c driver? Or the other drivers? Can you use grant-alloc for your code (which can setup shared memory segements between guests) instead of doing this in the kernel? > > I have explicitly specified the domid that can use the gref as > "domid_remote". > > What else can be wrong? > > On Thu, Nov 10, 2011 at 12:09 AM, Daniel Castro <evil.dani@xxxxxxxxx> wrote: > > > On Thu, Nov 10, 2011 at 1:15 PM, Xin Jin <jxinpku@xxxxxxxxx> wrote: > > > Hi, I cannot get a shared page in domU. > > > In a domU, I used the folloing code to grant a page to another domU. > > > share_mem = (share_mem_desp *) __get_free_page(GFP_KERNEL); > > > share_mem->gref = gnttab_grant_foreign_access(domid_remote, > > > virt_to_mfn(share_mem), 0); > > > In another domU, I used the folloing code to get the shared page. > > > share_vmarea = alloc_vm_area(PAGE_SIZE); > > > gnttab_set_map_op( &map_op, (unsigned long)share_vmarea->addr, > > > GNTMAP_host_map, gref, domid_remote ); > > > HYPERVISOR_grant_table_op( GNTTABOP_map_grant_ref, &map_op, 1 ); > > > While using the exactly same code to get the shared page in dom0, it woks > > > all well. But it cannot work in domU. > > > I use Xen 4.1.1 and fedora 14 ( linux 3.1.0 both for dom0 and domU ). > > > Can anyone help me? > > On the interface struct when you issue the hypercall you need to > > specify the domid that can use the gref. Maybe the default is domid 0. > > The struct grant_entry_v1 has member domid for the foreign guest, > > check that value. > > > > > Thanks! > > > -- Xin > > > > > > > > > _______________________________________________ > > > Xen-devel mailing list > > > Xen-devel@xxxxxxxxxxxxxxxxxxx > > > http://lists.xensource.com/xen-devel > > > > > > > > > > > > > > -- > > +-=====---------------------------+ > > | +---------------------------------+ | This space intentionally blank > > for notetaking. > > | | | Daniel Castro, | > > | | | Consultant/Programmer.| > > | | | U Andes | > > +-------------------------------------+ > > > > > > -- > Xin JIN > PhD student > Department of Computer Science > Princeton University > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxxxxxxxx > http://lists.xensource.com/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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