X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?a=blobdiff_plain;f=palacios%2Finclude%2Fgeekos%2Fvmm_paging.h;h=626049ce170cb50fd205e72375dc0a22c6309ff9;hb=271ad3fd89672d441db3c5ffa673ee649e4ce532;hp=6125d5da0bf7d4cc0be8f9a3804e9ecf518b5e79;hpb=122a7d532b4bb6914ff291d53f6111f1e52613b7;p=palacios.git

diff --git a/palacios/include/geekos/vmm_paging.h b/palacios/include/geekos/vmm_paging.h
index 6125d5d..626049c 100644
--- a/palacios/include/geekos/vmm_paging.h
+++ b/palacios/include/geekos/vmm_paging.h
@@ -1,6 +1,7 @@
 #ifndef __VMM_PAGING_H
 #define __VMM_PAGING_H
 
+
 #include <geekos/ktypes.h>
 
 
@@ -8,6 +9,73 @@
 #include <geekos/vmm_mem.h>
 #include <geekos/vmm_util.h>
 
+/*
+
+In the following, when we say "page table", we mean the whole 2 or 4 layer
+page table (PDEs, PTEs), etc.
+
+
+guest-visible paging state
+ This is the state that the guest thinks the machine is using
+ It consists of
+   - guest physical memory
+       The physical memory addresses the guest is allowed to use
+       (see shadow page maps, below)
+   - guest page tables 
+       (we care about when the current one changes)
+   - guest paging registers (these are never written to hardware)
+        CR0
+        CR3
+
+
+shadow paging state
+ This the state that the machine will actually use when the guest
+ is running.  It consists of:
+   - current shadow page table
+        This is the page table actually useed when the guest is running.
+        It is changed/regenerated when the guest page table changes
+        It mostly reflects the guest page table, except that it restricts 
+        physical addresses to those the VMM allocates to the guest.
+   - shadow page maps
+        This is a mapping from guest physical memory addresses to
+        the current location of the guest physical memory content.   
+        It maps from regions of physical memory addresses to regions 
+        located in physical memory or elsewhere.  
+        (8192,16384) -> MEM(8912,...)
+        (0,8191) -> DISK(65536,..) 
+   - guest paging registers (these are written to guest state)
+        CR0
+        CR3
+
+host paging state
+  This is the state we expect to be operative when the VMM is running.
+  Typically, this is set up by the host os into which we have embedded
+  the VMM, but we include the description here for clarity.
+    - current page table
+        This is the page table we use when we are executing in 
+        the VMM (or the host os)
+    - paging regisers
+        CR0
+        CR3
+
+
+The reason why the shadow paging state and the host paging state are
+distinct is to permit the guest to use any virtual address it wants,
+irrespective of the addresses the VMM or the host os use.  These guest
+virtual addresses are reflected in the shadow paging state.  When we
+exit from the guest, we switch to the host paging state so that any
+virtual addresses that overlap between the guest and VMM/host now map
+to the physical addresses epxected by the VMM/host.  On AMD SVM, this
+switch is done by the hardware.  On Intel VT, the switch is done
+by the hardware as well, but we are responsible for manually updating
+the host state in the vmcs before entering the guest.
+
+
+*/
+
+
+
+
 #define MAX_PAGE_TABLE_ENTRIES      1024
 #define MAX_PAGE_DIR_ENTRIES        1024
 
@@ -20,8 +88,10 @@
 #define PAGE_TABLE_INDEX(x)      ((((uint_t)x) >> 12) & 0x3ff)
 #define PAGE_OFFSET(x)           ((((uint_t)x) & 0xfff))
 
-#define PAGE_ALLIGNED_ADDR(x)   (((uint_t) (x)) >> 12)
-#define PAGE_ADDR(x)   (PAGE_ALLIGNED_ADDR(x) << 12)
+#define PAGE_ALIGNED_ADDR(x)   (((uint_t) (x)) >> 12)
+#ifndef PAGE_ADDR
+#define PAGE_ADDR(x)   (PAGE_ALIGNED_ADDR(x) << 12)
+#endif
 
 #define PAGE_POWER 12
 
@@ -122,10 +192,41 @@ typedef struct pml4e {
 } pml4e64_t;
 
 
-vmm_pde_t * generate_guest_page_tables(vmm_mem_layout_t * layout, vmm_mem_list_t * list);
-pml4e64_t * generate_guest_page_tables_64(vmm_mem_layout_t * layout, vmm_mem_list_t * list);
 
-void free_guest_page_tables(vmm_pde_t * pde);
+typedef enum { PDE32 } page_directory_type_t;
+
+
+typedef struct shadow_paging_state {
+  // these two reflect the top-level page directory
+  // of the guest page table
+  page_directory_type_t  guest_page_directory_type;
+  void                  *guest_page_directory;         // points to guest's current page table
+
+  // This reflects the guest physical to host physical mapping
+  shadow_map_t          shadow_map;
+
+  // these two reflect the top-level page directory 
+  // the shadow page table
+  page_directory_type_t  shadow_page_directory_type;
+  void                  *shadow_page_directory;
+ 
+} shadow_paging_state_t;
+
+
+
+int init_shadow_paging_state(shadow_paging_state_t *state);
+
+// This function will cause the shadow page table to be deleted
+// and rewritten to reflect the guest page table and the shadow map
+int wholesale_update_shadow_paging_state(shadow_paging_state_t *state);
+
+//void free_guest_page_tables(vmm_pde_t * pde);
+
+//generate_shadow_
+
+//vmm_pde_t * generate_guest_page_tables(shadow_map_t * map, vmm_mem_list_t * list);
+//pml4e64_t * generate_guest_page_tables_64(shadow_map_t * map, vmm_mem_list_t * list);
+
 
 void PrintDebugPageTables(vmm_pde_t * pde);