[Xen-devel] Review needed for "commonisation" of common/grant_table.c

["Magenheimer, Dan (HP Labs Fort Collins)" <dan.magenheimer@xxxxxx>]

common/grant_table.c is currently not built for Xen/ia64 and has
never been "common-ized".  I'm working on identifying the
x86-specific portions.  I have a version compiled and
minimally working on Xen/ia64 now but there's a lot of x86
code that should probably be moved to macros or to separate
arch-specific files and I would like to get
some review from a grant_table.c expert to ensure I haven't
missed (or misunderstood) anything.

Attached is a patch for grant_table.c.  It is NOT intended
to be applied, but to make the changes easier to review.  Apply
it to your local version of grant_table.c (rev 1.48, yesterday),
then look at each __ia64__.  Comments/feedback would be
greatly appreciated.

Thanks,
Dan

===== common/grant_table.c 1.48 vs edited =====
--- 1.48/xen/common/grant_table.c       Thu Jun  9 09:25:28 2005
+++ edited/common/grant_table.c Fri Jun 10 14:32:00 2005
@@ -30,6 +30,19 @@
 #include <xen/sched.h>
 #include <xen/shadow.h>
 #include <xen/mm.h>
+#ifdef __ia64__
+#define __addr_ok(a) 1 // FIXME-ia64: a variant of access_ok??
+// FIXME-ia64: need to implement real cmpxchg_user on ia64
+#define cmpxchg_user(_p,_o,_n) ((*_p == _o) ? ((*_p = _n), 0) : ((_o =
*_p), 0))
+// FIXME-ia64: the following are meaningless on ia64? move to some
header file
+#define put_page(x) do { } while (0)
+#define put_page_type(x) do { } while (0)
+// FIXME-ia64: these belong in an asm/grant_table.h... PAGE_SIZE
different
+#undef ORDER_GRANT_FRAMES
+//#undef NUM_GRANT_FRAMES
+#define ORDER_GRANT_FRAMES 0
+//#define NUM_GRANT_FRAMES  (1U << ORDER_GRANT_FRAMES)
+#endif
 
 #define PIN_FAIL(_lbl, _rc, _f, _a...)   \
     do {                           \
@@ -162,6 +175,9 @@
 
         frame = __gpfn_to_mfn_foreign(granting_d, sha->frame);
 
+#ifdef __ia64__
+// FIXME-ia64: any error checking need to be done here?
+#else
         if ( unlikely(!pfn_valid(frame)) ||
              unlikely(!((dev_hst_ro_flags & GNTMAP_readonly) ?
                         get_page(&frame_table[frame], granting_d) :
@@ -173,6 +189,7 @@
             PIN_FAIL(unlock_out, GNTST_general_error,
                      "Could not pin the granted frame (%lx)!\n",
frame);
         }
+#endif
 
         if ( dev_hst_ro_flags & GNTMAP_device_map )
             act->pin += (dev_hst_ro_flags & GNTMAP_readonly) ?
@@ -226,6 +243,9 @@
                 sflags = prev_sflags;
             }
 
+#ifdef __ia64__
+// FIXME-ia64: any error checking need to be done here?
+#else
             if ( unlikely(!get_page_type(&frame_table[frame],
                                          PGT_writable_page)) )
             {
@@ -233,6 +253,7 @@
                 PIN_FAIL(unlock_out, GNTST_general_error,
                          "Attempt to write-pin a unwritable page.\n");
             }
+#endif
         }
 
         if ( dev_hst_ro_flags & GNTMAP_device_map )
@@ -253,6 +274,9 @@
 
     spin_unlock(&granting_d->grant_table->lock);
 
+#ifdef __ia64__
+// FIXME-ia64: any error checking need to be done here?
+#else
     if ( (host_virt_addr != 0) && (dev_hst_ro_flags & GNTMAP_host_map)
)
     {
         /* Write update into the pagetable. */
@@ -298,6 +322,7 @@
         }
 
     }
+#endif
 
     *pframe = frame;
     return rc;
@@ -444,10 +469,14 @@
         if ( __gnttab_map_grant_ref(&uop[i], &va) == 0 )
             flush++;
 
+#ifdef __ia64__
+// FIXME-ia64: probably need to do something here to avoid stale
mappings?
+#else
     if ( flush == 1 )
         flush_tlb_one_mask(current->domain->cpumask, va);
     else if ( flush != 0 ) 
         flush_tlb_mask(current->domain->cpumask);
+#endif
 
     return 0;
 }
@@ -542,6 +571,9 @@
         /* Frame is now unmapped for device access. */
     }
 
+#ifdef __ia64__
+// FIXME-ia64: any error checking need to be done here?
+#else
     if ( (virt != 0) &&
          (flags & GNTMAP_host_map) &&
          ((act->pin & (GNTPIN_hstw_mask | GNTPIN_hstr_mask)) > 0))
@@ -596,6 +628,7 @@
         rc = 0;
         *va = virt;
     }
+#endif
 
     if ( (map->ref_and_flags & (GNTMAP_device_map|GNTMAP_host_map)) ==
0)
     {
@@ -603,10 +636,15 @@
         put_maptrack_handle(ld->grant_table, handle);
     }
 
+#ifdef __ia64__
+// FIXME-ia64: any error checking need to be done here?  I think not
and then
+//  this can probably be macro-ized into nothingness
+#else
     /* If just unmapped a writable mapping, mark as dirtied */
     if ( unlikely(shadow_mode_log_dirty(rd)) &&
         !( flags & GNTMAP_readonly ) )
          mark_dirty(rd, frame);
+#endif
 
     /* If the last writable mapping has been removed, put_page_type */
     if ( ( (act->pin & (GNTPIN_devw_mask|GNTPIN_hstw_mask) ) == 0) &&
@@ -640,10 +678,14 @@
         if ( __gnttab_unmap_grant_ref(&uop[i], &va) == 0 )
             flush++;
 
+#ifdef __ia64__
+// FIXME-ia64: probably need to do something here to avoid stale
mappings?
+#else
     if ( flush == 1 )
         flush_tlb_one_mask(current->domain->cpumask, va);
     else if ( flush != 0 ) 
         flush_tlb_mask(current->domain->cpumask);
+#endif
 
     return 0;
 }
@@ -1050,6 +1092,9 @@
 
     spin_lock(&rd->grant_table->lock);
 
+#ifdef __ia64__
+// FIXME-ia64: any error checking need to be done here?
+#else
     pfn = sha->frame;
 
     if ( unlikely(pfn >= max_page ) )
@@ -1064,6 +1109,7 @@
         if (shadow_mode_translate(ld))
             __phys_to_machine_mapping[pfn] = frame;
     }
+#endif
     sha->frame = __mfn_to_gpfn(rd, frame);
     sha->domid = rd->domain_id;
     wmb();
@@ -1109,6 +1155,9 @@
         goto no_mem;
     memset(t->shared, 0, NR_GRANT_FRAMES * PAGE_SIZE);
 
+#ifdef __ia64__
+// I don't think there's anything to do here on ia64?...
+#else
     for ( i = 0; i < NR_GRANT_FRAMES; i++ )
     {
         SHARE_PFN_WITH_DOMAIN(
@@ -1116,6 +1165,7 @@
         machine_to_phys_mapping[(virt_to_phys(t->shared) >> PAGE_SHIFT)
+ i] =
             INVALID_M2P_ENTRY;
     }
+#endif
 
     /* Okay, install the structure. */
     wmb(); /* avoid races with lock-free access to d->grant_table */

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