[Xen-devel] [v3 02/10] log-dirty: add new paging_mark_gfn_dirty

[Kai Huang <kai.huang@xxxxxxxxxxxxxxx>]

PML logs GPA in PML buffer. Original paging_mark_dirty takes MFN as parameter
but it gets guest pfn internally and use guest pfn to as index for looking up
radix log-dirty tree. In flushing PML buffer, calling paging_mark_dirty directly
introduces redundant p2m lookups (gfn->mfn->gfn), therefore we introduce
paging_mark_gfn_dirty which is bulk of paging_mark_dirty but takes guest pfn as
parameter, and in flushing PML buffer we call paging_mark_gfn_dirty directly.
Original paging_mark_dirty then simply is a wrapper of paging_mark_gfn_dirty.

Signed-off-by: Kai Huang <kai.huang@xxxxxxxxxxxxxxx>
---
 xen/arch/x86/mm/paging.c     | 31 +++++++++++++++++++++----------
 xen/include/asm-x86/paging.h |  2 ++
 2 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/xen/arch/x86/mm/paging.c b/xen/arch/x86/mm/paging.c
index b54d76a..77c929b 100644
--- a/xen/arch/x86/mm/paging.c
+++ b/xen/arch/x86/mm/paging.c
@@ -266,24 +266,17 @@ static int paging_log_dirty_disable(struct domain *d, 
bool_t resuming)
     return ret;
 }
 
-/* Mark a page as dirty */
-void paging_mark_dirty(struct domain *d, unsigned long guest_mfn)
+/* Mark a page as dirty, with taking guest pfn as parameter */
+void paging_mark_gfn_dirty(struct domain *d, unsigned long pfn)
 {
-    unsigned long pfn;
-    mfn_t gmfn;
     int changed;
     mfn_t mfn, *l4, *l3, *l2;
     unsigned long *l1;
     int i1, i2, i3, i4;
 
-    gmfn = _mfn(guest_mfn);
-
-    if ( !paging_mode_log_dirty(d) || !mfn_valid(gmfn) ||
-         page_get_owner(mfn_to_page(gmfn)) != d )
+    if ( !paging_mode_log_dirty(d) )
         return;
 
-    /* We /really/ mean PFN here, even for non-translated guests. */
-    pfn = get_gpfn_from_mfn(mfn_x(gmfn));
     /* Shared MFNs should NEVER be marked dirty */
     BUG_ON(SHARED_M2P(pfn));
 
@@ -351,6 +344,24 @@ out:
     return;
 }
 
+/* Mark a page as dirty */
+void paging_mark_dirty(struct domain *d, unsigned long guest_mfn)
+{
+    unsigned long pfn;
+    mfn_t gmfn;
+
+    gmfn = _mfn(guest_mfn);
+
+    if ( !paging_mode_log_dirty(d) || !mfn_valid(gmfn) ||
+         page_get_owner(mfn_to_page(gmfn)) != d )
+        return;
+
+    /* We /really/ mean PFN here, even for non-translated guests. */
+    pfn = get_gpfn_from_mfn(mfn_x(gmfn));
+
+    paging_mark_gfn_dirty(d, pfn);
+}
+
 
 /* Is this guest page dirty? */
 int paging_mfn_is_dirty(struct domain *d, mfn_t gmfn)
diff --git a/xen/include/asm-x86/paging.h b/xen/include/asm-x86/paging.h
index 53de715..c99324c 100644
--- a/xen/include/asm-x86/paging.h
+++ b/xen/include/asm-x86/paging.h
@@ -156,6 +156,8 @@ void paging_log_dirty_init(struct domain *d,
 
 /* mark a page as dirty */
 void paging_mark_dirty(struct domain *d, unsigned long guest_mfn);
+/* mark a page as dirty with taking guest pfn as parameter */
+void paging_mark_gfn_dirty(struct domain *d, unsigned long pfn);
 
 /* is this guest page dirty? 
  * This is called from inside paging code, with the paging lock held. */
-- 
2.1.0


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