[Xen-devel] [PATCH v2 11/22] mini-os: add static page tables for virtual kernel area for HVMlite

[Juergen Gross <jgross@xxxxxxxx>]

In HVMlite mode we need the virtual kernel area for mapping of the
console and xenbus ring pages as especially on 32 bit architecture
their pfns might be above the supported maximum memory size.

Add the page tables needed for doing the mapping.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Reviewed-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>
---
 arch/x86/mm.c     | 11 +++++++++++
 arch/x86/x86_64.S |  7 +++++++
 2 files changed, 18 insertions(+)

diff --git a/arch/x86/mm.c b/arch/x86/mm.c
index 0543017..cbb5617 100644
--- a/arch/x86/mm.c
+++ b/arch/x86/mm.c
@@ -733,6 +733,17 @@ void arch_init_mm(unsigned long* start_pfn_p, unsigned 
long* max_pfn_p)
 
     *start_pfn_p = start_pfn;
     *max_pfn_p = max_pfn;
+
+#ifndef CONFIG_PARAVIRT
+#ifdef __x86_64__
+    BUILD_BUG_ON(l4_table_offset(VIRT_KERNEL_AREA) != 1 ||
+                 l3_table_offset(VIRT_KERNEL_AREA) != 0 ||
+                 l2_table_offset(VIRT_KERNEL_AREA) != 0);
+#else
+    BUILD_BUG_ON(l3_table_offset(VIRT_KERNEL_AREA) != 0 ||
+                 l2_table_offset(VIRT_KERNEL_AREA) == 0);
+#endif
+#endif
 }
 
 grant_entry_t *arch_init_gnttab(int nr_grant_frames)
diff --git a/arch/x86/x86_64.S b/arch/x86/x86_64.S
index 17a9ead..5932bfb 100644
--- a/arch/x86/x86_64.S
+++ b/arch/x86/x86_64.S
@@ -418,10 +418,17 @@ ENTRY(__arch_switch_threads)
 .data
 .globl page_table_base
         .align __PAGE_SIZE
+page_table_virt_l2:
+        PTE(page_table_virt_l1 + L2_PROT)
+        .align __PAGE_SIZE, 0
+page_table_virt_l3:
+        PTE(page_table_virt_l2 + L3_PROT)
+        .align __PAGE_SIZE, 0
 page_table_l3:
         PTE(page_table_l2 + L3_PROT)
         .align __PAGE_SIZE, 0
 page_table_base:
         PTE(page_table_l3 + L4_PROT)
+        PTE(page_table_virt_l3 + L4_PROT)
         .align __PAGE_SIZE, 0
 #endif
-- 
2.6.6


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