#ifndef __VMM_PAGING_H
#define __VMM_PAGING_H
+
#include <geekos/ktypes.h>
#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
#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
} 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);
