[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-devel] [PATCH 6/6] Change MMU_PT_UPDATE_RESERVE_AD to support update page table for foreign domain
I want to clarify that this patch need more discussion because there is no clear way to distinguish if the page table address (i.e. address passed in req[:2] ) is owned by the current domain or by the foreign domain. So I just try to check if mfn_valid(), but I suspect if this is the right method. Thanks Yunhong Jiang xen-devel-bounces@xxxxxxxxxxxxxxxxxxx wrote: > foreign domain > > Currently MMU_PT_UPDATE_RESERVE_AD support only update page > table for current domain. This patch add support for foreign > domain also. > > Signed-off-by: Jiang, Yunhong <yunhong.jiang@xxxxxxxxx> Update > the page table update hypercall > > diff -r f6457425560b xen/arch/x86/mm.c > --- a/xen/arch/x86/mm.c Wed May 27 03:22:43 2009 +0800 > +++ b/xen/arch/x86/mm.c Wed May 27 03:40:38 2009 +0800 @@ -110,6 > +110,7 @@ #include <asm/hypercall.h> > #include <asm/shared.h> > #include <public/memory.h> > +#include <public/sched.h> > #include <xsm/xsm.h> > #include <xen/trace.h> > > @@ -2990,7 +2991,8 @@ int do_mmu_update( > struct page_info *page; > int rc = 0, okay = 1, i = 0; > unsigned int cmd, done = 0; > - struct domain *d = current->domain; > + struct domain *d = current->domain, *pt_owner = NULL; > + struct vcpu *v = current; > struct domain_mmap_cache mapcache; > > if ( unlikely(count & MMU_UPDATE_PREEMPTED) ) > @@ -3051,10 +3053,35 @@ int do_mmu_update( > gmfn = req.ptr >> PAGE_SHIFT; > mfn = gmfn_to_mfn(d, gmfn); > > - if ( unlikely(!get_page_from_pagenr(mfn, d)) ) > + if (!mfn_valid(mfn)) > + mfn = gmfn_to_mfn(FOREIGNDOM, gmfn); > + if (!mfn_valid(mfn)) > { > MEM_LOG("Could not get page for normal update"); > break; + } > + > + pt_owner = > page_get_owner_and_reference(mfn_to_page(mfn)); + + if ( > pt_owner != d ) + { > + if ( pt_owner == FOREIGNDOM ) > + { > + spin_lock(&FOREIGNDOM->shutdown_lock); > + if ( !IS_PRIV(d) || > + !FOREIGNDOM->is_shut_down || > + (FOREIGNDOM->shutdown_code != > SHUTDOWN_suspend) ) + { > + spin_unlock(&FOREIGNDOM->shutdown_lock); > + rc = -EPERM; > + break; > + } > + v = FOREIGNDOM->vcpu[0]; > + }else > + { > + rc = -EPERM; > + break; > + } > } > > va = map_domain_page_with_cache(mfn, &mapcache); > @@ -3070,24 +3097,21 @@ int do_mmu_update( > { > l1_pgentry_t l1e = l1e_from_intpte(req.val); > okay = mod_l1_entry(va, l1e, mfn, > - cmd == > MMU_PT_UPDATE_PRESERVE_AD, > - current); > + cmd == > MMU_PT_UPDATE_PRESERVE_AD, v); > } > break; > case PGT_l2_page_table: > { > l2_pgentry_t l2e = l2e_from_intpte(req.val); > okay = mod_l2_entry(va, l2e, mfn, > - cmd == > MMU_PT_UPDATE_PRESERVE_AD, > - current); > + cmd == > MMU_PT_UPDATE_PRESERVE_AD, v); > } > break; > case PGT_l3_page_table: > { > l3_pgentry_t l3e = l3e_from_intpte(req.val); > rc = mod_l3_entry(va, l3e, mfn, > - cmd == > MMU_PT_UPDATE_PRESERVE_AD, 1, > - current); > + cmd == > MMU_PT_UPDATE_PRESERVE_AD, 1, v); > okay = !rc; > } > break; > @@ -3096,8 +3120,7 @@ int do_mmu_update( > { > l4_pgentry_t l4e = l4e_from_intpte(req.val); > rc = mod_l4_entry(va, l4e, mfn, > - cmd == > MMU_PT_UPDATE_PRESERVE_AD, 1, > - current); > + cmd == > MMU_PT_UPDATE_PRESERVE_AD, 1, v); > okay = !rc; > } > break; > @@ -3105,7 +3128,7 @@ int do_mmu_update( > case PGT_writable_page: > perfc_incr(writable_mmu_updates); > okay = paging_write_guest_entry( > - current, va, req.val, _mfn(mfn)); > + v, va, req.val, _mfn(mfn)); > break; } > page_unlock(page); > @@ -3116,11 +3139,13 @@ int do_mmu_update( > { > perfc_incr(writable_mmu_updates); > okay = paging_write_guest_entry( > - current, va, req.val, _mfn(mfn)); > + v, va, req.val, _mfn(mfn)); > put_page_type(page); > } > > unmap_domain_page_with_cache(va, &mapcache); > + if (pt_owner != d) > + spin_unlock(&FOREIGNDOM->shutdown_lock); > put_page(page); break; > > diff -r f6457425560b xen/include/public/xen.h > --- a/xen/include/public/xen.h Wed May 27 03:22:43 2009 +0800 > +++ b/xen/include/public/xen.h Wed May 27 03:26:46 2009 +0800 > @@ -170,6 +170,8 @@ DEFINE_XEN_GUEST_HANDLE(xen_pfn_t); > * table entry is valid/present, the mapped frame must belong > to the FD, if > * an FD has been specified. If attempting to map an I/O page then the > * caller assumes the privilege of the FD. > + * The page table entry normally belongs to the calling > domain. Otherwise it > + * should belong to the FD and the FD should be suspended already > * FD == DOMID_IO: Permit /only/ I/O mappings, at the priv > level of the caller. > * FD == DOMID_XEN: Map restricted areas of Xen's heap space. > * ptr[:2] -- Machine address of the page-table entry to modify. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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