if ( unlikely(cmpxchg_user(&sha->flags, prev_sflags,
prev_sflags | GTF_writing)) )
PIN_FAIL(GNTST_general_error,
- "Fault while modifying shared flags.\n");
+ "Fault while modifying shared flags.\n");
if ( likely(prev_sflags == sflags) )
break;
ld->grant_table->maptrack[handle].ref_and_flags =
(ref << MAPTRACK_REF_SHIFT) | (flags & MAPTRACK_GNTMAP_MASK);
+ /* At this point:
+ * act->pin updated to reflect mapping
+ * sha->flags updated to indicate to granting domain mapping done
+ * maptrack points to correct remote domain data
+ * frame contains the mfn
+ */
+
if ( (host_virt_addr != 0) && (flags & GNTMAP_host_map) )
{
/* Write update into the pagetable
{
act->pin -= GNTPIN_hstw_inc;
if ( (act->pin & (GNTPIN_hstw_mask | GNTPIN_hstr_mask)) == 0 )
+ {
put_page_type(&frame_table[frame]);
+ clear_bit(_GTF_writing, &sha->flags);
+ }
if ( act->pin == 0 )
+ {
put_page(&frame_table[frame]);
+ clear_bit(_GTF_reading, &sha->flags);
+ }
}
goto fail;
}
+ /* Check to see if update overwrote a mapping of the same mfn
+ * - if so, must handle ref count here
+ */
if ( rc == GNTUPDVA_prev_ro )
act->pin -= GNTPIN_hstr_inc;
if ( rc == GNTUPDVA_prev_rw )
{
act->pin -= GNTPIN_hstw_inc;
- put_page_type(&frame_table[frame]);
+
+ if ( (act->pin & (GNTPIN_hstw_mask | GNTPIN_devw_mask)) == 0 )
+ {
+ put_page_type(&frame_table[frame]);
+ clear_bit(_GTF_writing, &sha->flags);
+ }
}
rc = 0;
*va = host_virt_addr;
*/
}
+ /* Unchecked and unconditional writes to user uop. */
if ( flags & GNTMAP_device_map )
(void)__put_user(frame, &uop->dev_bus_addr);
- /* Unchecked and unconditional. */
(void)__put_user(handle, &uop->handle);
spin_unlock(&rd->grant_table->lock);
(void)__put_user(rc, &uop->handle);
spin_unlock(&rd->grant_table->lock);
put_domain(rd);
- put_maptrack_handle(ld->grant_table, handle); //cwc22: check this
+ put_maptrack_handle(ld->grant_table, handle);
return rc;
}
if ( flush == 1 )
__flush_tlb_one(va);
+
else if ( flush )
local_flush_tlb();
+
return 0;
}
GNTPIN_devr_inc : GNTPIN_devw_inc;
}
else
- {
frame = act->frame;
- }
+
if ( (virt != 0) &&
(map->ref_and_flags & GNTMAP_host_map) &&
goto fail;
}
- /* This code _requires_ that the act->pin bits are updated
- * if a mapping is ever switched between RO and RW.
- */
- act->pin -= ( _ol1e & _PAGE_RW ) ? GNTPIN_hstw_inc
- : GNTPIN_hstr_inc;
-
/* Delete pagetable entry
*/
if ( unlikely(__put_user(0, (unsigned long *)pl1e)))
rc = -EINVAL;
goto fail;
}
+
+ act->pin -= (map->ref_and_flags & GNTMAP_readonly) ?
+ GNTPIN_hstr_inc : GNTPIN_hstw_inc;
+
rc = 0;
*va = virt;
}
if ( flush == 1 )
__flush_tlb_one(va);
+
else if ( flush )
local_flush_tlb();
+
return 0;
}
gnttab_check_unmap(
struct domain *rd, struct domain *ld, unsigned long frame, int readonly)
{
- /* TODO: beat the caller around the head with a brick.
- * have to walk the grant tables to find this thing.
+ /* Called when put_page is invoked on a page belonging to a foreign domain.
+ * Instead of decrementing the frame table ref count, locate the grant
+ * table entry, if any, and if found, decrement that count.
+ * Called a _lot_ at domain creation because pages mapped by priv domains
+ * also traverse this.
*/
- /*DPRINTK("gnttab_check_unmap remote dom(%d) local dom(%d) frame (%x) flags(%x).\n",
- rd->id, ld->id, frame, readonly);*/
- return 0;
+
+ unsigned int handle, ref, refcount;
+ grant_table_t *lgt, *rgt;
+ active_grant_entry_t *act;
+ grant_mapping_t *map;
+ int found = 0;
+
+ lgt = ld->grant_table;
+ rgt = rd->grant_table;
+
+ if ( ld->id != 0 ) {
+ DPRINTK("Foreign unref rd(%d) ld(%d) frm(%x) flgs(%x).\n",
+ rd->id, ld->id, frame, readonly);
+ }
+
+ for ( handle = 0; handle < NR_MAPTRACK_ENTRIES; handle++ )
+ {
+ map = &lgt->maptrack[handle];
+
+
+ /* cwc22: if multiple grants of the same frame are disallowed,
+ * then the readonly check here can be changed to cause an early abort
+ * if we've matched on frame, but not on write permission.
+ */
+ if ( ( map->ref_and_flags & MAPTRACK_GNTMAP_MASK ) &&
+ ( readonly ? 1 : (!(map->ref_and_flags & GNTMAP_readonly))))
+ {
+ ref = (map->ref_and_flags >> MAPTRACK_REF_SHIFT);
+ act = &rgt->active[ref];
+
+ spin_lock(&rgt->lock);
+
+ if ( act->frame != frame )
+ {
+ spin_unlock(&rgt->lock);
+ continue;
+ }
+
+ refcount = act->pin & ( readonly ? GNTPIN_hstr_mask
+ : GNTPIN_hstw_mask );
+ if ( refcount == 0 )
+ {
+ spin_unlock(&rgt->lock);
+ continue;
+ }
+
+ /* gotcha */
+ DPRINTK("Grant unref rd(%d) ld(%d) frm(%x) flgs(%x).\n",
+ rd->id, ld->id, frame, readonly);
+
+ if ( readonly )
+ act->pin -= GNTPIN_hstr_inc;
+ else
+ {
+ act->pin -= GNTPIN_hstw_inc;
+
+ /* any more granted writable mappings? */
+ if ( (act->pin & (GNTPIN_hstw_mask | GNTPIN_hstr_mask)) == 0 )
+ {
+ put_page_type(&frame_table[frame]);
+ clear_bit(_GTF_writing, &rgt->shared[ref].flags);
+ }
+ }
+
+ if ( act->pin == 0 )
+ {
+ put_page(&frame_table[frame]);
+ clear_bit(_GTF_reading, &rgt->shared[ref].flags);
+ }
+ spin_unlock(&rgt->lock);
+
+ clear_bit(GNTMAP_host_map, &map->ref_and_flags);
+
+ if ( !(map->ref_and_flags & GNTMAP_device_map) )
+ put_maptrack_handle(lgt, handle);
+
+ found = 1;
+ break;
+ }
+ }
+
+ return found;
}
int
return -ENOMEM;
}
-void
-gnttab_release_all_mappings(grant_table_t *gt)
-{
- grant_mapping_t *map;
- domid_t dom;
- grant_ref_t ref;
- u16 handle;
- u32 pincount;
- struct domain *ld, *rd;
- unsigned long frame;
- active_grant_entry_t *act;
- grant_entry_t *sha;
-
- ld = current->domain;
-
- for ( handle = 0; handle < NR_MAPTRACK_ENTRIES; handle++ )
- {
- map = >->maptrack[handle];
-
- if ( map->ref_and_flags & MAPTRACK_GNTMAP_MASK )
- {
- dom = map->domid;
- ref = map->ref_and_flags >> MAPTRACK_REF_SHIFT;
-
- DPRINTK("Grant release (%hu) ref:(%hu) flags:(%x) dom:(%hu)\n",
- handle, ref,
- map->ref_and_flags & MAPTRACK_GNTMAP_MASK, dom);
-
- if ( unlikely((rd = find_domain_by_id(dom)) == NULL) ||
- unlikely(ld == rd) )
- {
- if ( rd != NULL )
- put_domain(rd);
-
- printk(KERN_WARNING "Grant release: Could not find domain %d\n", dom);
- continue;
- }
-
- act = &rd->grant_table->active[ref];
- sha = &rd->grant_table->shared[ref];
-
- spin_lock(&rd->grant_table->lock);
-
- frame = act->frame;
-
- pincount = ((act->pin & GNTPIN_hstw_mask) >> GNTPIN_hstw_shift) +
- ((act->pin & GNTPIN_devw_mask) >> GNTPIN_devw_shift);
-
- if ( pincount > 0 )
- put_page_type(&frame_table[frame]);
-
- if (act->pin)
- put_page(&frame_table[frame]);
-
- act->pin = 0;
-
- clear_bit(_GTF_reading, &sha->flags);
- clear_bit(_GTF_writing, &sha->flags);
-
- spin_unlock(&rd->grant_table->lock);
-
- map->ref_and_flags = 0;
-
- put_domain(rd);
- }
- }
-}
-
void
grant_table_destroy(
struct domain *d)
if ( (t = d->grant_table) != NULL )
{
- if ( t->maptrack != NULL )
- gnttab_release_all_mappings(t);
-
/* Free memory relating to this grant table. */
d->grant_table = NULL;
free_xenheap_page((unsigned long)t->shared);
projects / xen.git / commitdiff