[Xen-devel] [PATCH] bypass passthrough MMIO mfns in vram dirty logic

["He, Qing" <qing.he@xxxxxxxxx>]

This patch fixes the fatal page fault when vram dirty logic handles MMIO
of passthrough devices.

Signed-off-by: Qing He <qing.he@xxxxxxxxx>
---


diff -r 810d8c3ac992 xen/arch/x86/mm/shadow/multi.c
--- a/xen/arch/x86/mm/shadow/multi.c    Thu May 08 16:58:33 2008 +0100
+++ b/xen/arch/x86/mm/shadow/multi.c    Tue May 13 00:19:08 2008 +0800
@@ -1268,6 +1268,9 @@ static inline void shadow_vram_get_l1e(s
     if ( !d->dirty_vram ) return;
 
     mfn = shadow_l1e_get_mfn(new_sl1e);
+
+    if ( !mfn_valid(mfn) ) return; /* m2p for mmio_direct may not exist
*/
+
     gfn = mfn_to_gfn(d, mfn);
 
     if ( (gfn >= d->dirty_vram->begin_pfn) && (gfn <
d->dirty_vram->end_pfn) ) {
@@ -1293,6 +1296,9 @@ static inline void shadow_vram_put_l1e(s
     if ( !d->dirty_vram ) return;
 
     mfn = shadow_l1e_get_mfn(old_sl1e);
+
+    if ( !mfn_valid(mfn) ) return;
+
     gfn = mfn_to_gfn(d, mfn);
 
     if ( (gfn >= d->dirty_vram->begin_pfn) && (gfn <
d->dirty_vram->end_pfn) ) {

Attachment: vram-dirty-bypass-mmio-direct.patch
Description: vram-dirty-bypass-mmio-direct.patch

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