Mailing List Archive

# HG changeset patch
# User Keir Fraser <keir.fraser@citrix.com>
# Date 1276245074 -3600
# Node ID 2e38205b0d736bea92c3909cff6b363809f89d91
# Parent 04e81a65d27ef09654cd731735fc6a4ebc6314d4
grant iommu: Correctly handle multiple mappings of same MFN.

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
---
xen/common/grant_table.c | 44 ++++++++++++++++++++++++++++++++++++++------
1 files changed, 38 insertions(+), 6 deletions(-)

diff -r 04e81a65d27e -r 2e38205b0d73 xen/common/grant_table.c
--- a/xen/common/grant_table.c Thu Jun 10 22:39:52 2010 +0100
+++ b/xen/common/grant_table.c Fri Jun 11 09:31:14 2010 +0100
@@ -393,6 +393,29 @@ static int _set_status(unsigned gt_versi
return _set_status_v2(domid, readonly, mapflag, shah, act, status);
}

+static void mapcount(
+ struct domain *ld, unsigned long mfn,
+ unsigned int *wrc, unsigned int *rdc)
+{
+ struct grant_table *gt = ld->grant_table;
+ struct grant_mapping *map;
+ grant_handle_t handle;
+ struct domain *rd;
+
+ *wrc = *rdc = 0;
+
+ for ( handle = 0; handle < gt->maptrack_limit; handle++ )
+ {
+ map = &maptrack_entry(gt, handle);
+ if ( !(map->flags & (GNTMAP_device_map|GNTMAP_host_map)) )
+ continue;
+ rd = rcu_lock_domain_by_id(map->domid);
+ if ( active_entry(rd->grant_table, map->ref).frame == mfn )
+ (map->flags & GNTMAP_readonly) ? (*rdc)++ : (*wrc)++;
+ rcu_unlock_domain(rd);
+ }
+}
+
/*
* Returns 0 if TLB flush / invalidate required by caller.
* va will indicate the address to be invalidated.
@@ -598,17 +621,25 @@ __gnttab_map_grant_ref(

if ( !is_hvm_domain(ld) && need_iommu(ld) )
{
+ unsigned int wrc, rdc;
int err = 0;
/* Shouldn't happen, because you can't use iommu in a HVM domain. */
BUG_ON(paging_mode_translate(ld));
/* We're not translated, so we know that gmfns and mfns are
the same things, so the IOMMU entry is always 1-to-1. */
+ mapcount(ld, frame, &wrc, &rdc);
if ( (act_pin & (GNTPIN_hstw_mask|GNTPIN_devw_mask)) &&
!(old_pin & (GNTPIN_hstw_mask|GNTPIN_devw_mask)) )
- err = iommu_map_page(ld, frame, frame,
- IOMMUF_readable|IOMMUF_writable);
+ {
+ if ( wrc == 0 )
+ err = iommu_map_page(ld, frame, frame,
+ IOMMUF_readable|IOMMUF_writable);
+ }
else if ( act_pin && !old_pin )
- err = iommu_map_page(ld, frame, frame, IOMMUF_readable);
+ {
+ if ( (wrc + rdc) == 0 )
+ err = iommu_map_page(ld, frame, frame, IOMMUF_readable);
+ }
if ( err )
{
rc = GNTST_general_error;
@@ -785,12 +816,13 @@ __gnttab_unmap_common(

if ( !is_hvm_domain(ld) && need_iommu(ld) )
{
+ unsigned int wrc, rdc;
int err = 0;
BUG_ON(paging_mode_translate(ld));
- if ( old_pin && !act->pin )
+ mapcount(ld, op->frame, &wrc, &rdc);
+ if ( (wrc + rdc) == 0 )
err = iommu_unmap_page(ld, op->frame);
- else if ( (old_pin & (GNTPIN_hstw_mask|GNTPIN_devw_mask)) &&
- !(act->pin & (GNTPIN_hstw_mask|GNTPIN_devw_mask)) )
+ else if ( wrc == 0 )
err = iommu_map_page(ld, op->frame, op->frame, IOMMUF_readable);
if ( err )
{

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