[Xen-devel] [PATCH v2 08/17] Save/Restore Support: Add arch_mm_pre|post_suspend

[Bruno Alvisio <bruno.alvisio@xxxxxxxxx>]

For PV guests the pagetables reference the real MFNs rather than PFNs, so when
the guest is resumed into a different area of a hosts memory, these will need to
be rewritten. Thus for PV guests the MFNs need to be replaced with PFNs:
canonicalization.

PVH guests are auto-translated so no memory operation is needed.

Signed-off-by: Bruno Alvisio <bruno.alvisio@xxxxxxxxx>
Reviewed-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>
---
 arch/x86/mm.c         | 14 ++++++++++++++
 include/x86/arch_mm.h |  3 +++
 2 files changed, 17 insertions(+)

diff --git a/arch/x86/mm.c b/arch/x86/mm.c
index 05ad029..1b163ac 100644
--- a/arch/x86/mm.c
+++ b/arch/x86/mm.c
@@ -848,6 +848,20 @@ void arch_init_p2m(unsigned long max_pfn)
 
     arch_remap_p2m(max_pfn);
 }
+
+void arch_mm_pre_suspend(void)
+{
+    //TODO: Canonicalize pagetables
+}
+
+void arch_mm_post_suspend(int canceled)
+{
+    //TODO: Locate pagetables and 'uncanonicalize' them
+}
+#else
+void arch_mm_pre_suspend(void){ }
+
+void arch_mm_post_suspend(int canceled){ }
 #endif
 
 void arch_init_mm(unsigned long* start_pfn_p, unsigned long* max_pfn_p)
diff --git a/include/x86/arch_mm.h b/include/x86/arch_mm.h
index ab8a53e..cbbeb21 100644
--- a/include/x86/arch_mm.h
+++ b/include/x86/arch_mm.h
@@ -279,6 +279,9 @@ pgentry_t *need_pgt(unsigned long addr);
 void arch_mm_preinit(void *p);
 unsigned long alloc_virt_kernel(unsigned n_pages);
 
+void arch_mm_pre_suspend(void);
+void arch_mm_post_suspend(int canceled);
+
 #ifndef CONFIG_PARAVIRT
 void arch_print_memmap(void);
 #endif
-- 
2.3.2 (Apple Git-55)


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