[PATCH RFC 32/55] efi: switch EFI L4 table to use new APIs

[Wei Liu <wei.liu2@citrix.com>]

This requires storing the MFN instead of linear address of the L4
table. Adjust code accordingly.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 xen/arch/x86/efi/runtime.h | 12 +++++++++---
 xen/common/efi/boot.c      |  8 ++++++--
 xen/common/efi/efi.h       |  3 ++-
 xen/common/efi/runtime.c   |  8 ++++----
 4 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/xen/arch/x86/efi/runtime.h b/xen/arch/x86/efi/runtime.h
index d9eb8f5c27..277d237953 100644
--- a/xen/arch/x86/efi/runtime.h
+++ b/xen/arch/x86/efi/runtime.h
@@ -2,11 +2,17 @@
 #include <asm/mc146818rtc.h>
 
 #ifndef COMPAT
-l4_pgentry_t *__read_mostly efi_l4_pgtable;
+mfn_t __read_mostly efi_l4_mfn = INVALID_MFN_INITIALIZER;
 
 void efi_update_l4_pgtable(unsigned int l4idx, l4_pgentry_t l4e)
 {
-    if ( efi_l4_pgtable )
-        l4e_write(efi_l4_pgtable + l4idx, l4e);
+    if ( !mfn_eq(efi_l4_mfn, INVALID_MFN) )
+    {
+        l4_pgentry_t *l4t;
+
+        l4t = map_xen_pagetable_new(efi_l4_mfn);
+        l4e_write(l4t + l4idx, l4e);
+        UNMAP_XEN_PAGETABLE_NEW(l4t);
+    }
 }
 #endif
diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
index 3868293d06..f55d6a6d76 100644
--- a/xen/common/efi/boot.c
+++ b/xen/common/efi/boot.c
@@ -1488,6 +1488,7 @@ void __init efi_init_memory(void)
         unsigned int prot;
     } *extra, *extra_head = NULL;
 #endif
+    l4_pgentry_t *efi_l4_pgtable;
 
     free_ebmalloc_unused_mem();
 
@@ -1603,8 +1604,9 @@ void __init efi_init_memory(void)
                                  mdesc_ver, efi_memmap);
 #else
     /* Set up 1:1 page tables to do runtime calls in "physical" mode. */
-    efi_l4_pgtable = alloc_xen_pagetable();
-    BUG_ON(!efi_l4_pgtable);
+    efi_l4_mfn = alloc_xen_pagetable_new();
+    BUG_ON(mfn_eq(efi_l4_mfn, INVALID_MFN));
+    efi_l4_pgtable = map_xen_pagetable_new(efi_l4_mfn);
     clear_page(efi_l4_pgtable);
 
     copy_mapping(efi_l4_pgtable, 0, max_page, ram_range_valid);
@@ -1703,6 +1705,8 @@ void __init efi_init_memory(void)
           i < l4_table_offset(DIRECTMAP_VIRT_END); ++i )
         efi_l4_pgtable[i] = idle_pg_table[i];
 #endif
+
+    UNMAP_XEN_PAGETABLE_NEW(efi_l4_pgtable);
 }
 #endif
 
diff --git a/xen/common/efi/efi.h b/xen/common/efi/efi.h
index 6b9c56ead1..139b660ed7 100644
--- a/xen/common/efi/efi.h
+++ b/xen/common/efi/efi.h
@@ -6,6 +6,7 @@
 #include <efi/eficapsule.h>
 #include <efi/efiapi.h>
 #include <xen/efi.h>
+#include <xen/mm.h>
 #include <xen/spinlock.h>
 #include <asm/page.h>
 
@@ -29,7 +30,7 @@ extern UINTN efi_memmap_size, efi_mdesc_size;
 extern void *efi_memmap;
 
 #ifdef CONFIG_X86
-extern l4_pgentry_t *efi_l4_pgtable;
+extern mfn_t efi_l4_mfn;
 #endif
 
 extern const struct efi_pci_rom *efi_pci_roms;
diff --git a/xen/common/efi/runtime.c b/xen/common/efi/runtime.c
index 3d118d571d..8263f1d863 100644
--- a/xen/common/efi/runtime.c
+++ b/xen/common/efi/runtime.c
@@ -85,7 +85,7 @@ struct efi_rs_state efi_rs_enter(void)
     static const u32 mxcsr = MXCSR_DEFAULT;
     struct efi_rs_state state = { .cr3 = 0 };
 
-    if ( !efi_l4_pgtable )
+    if ( mfn_eq(efi_l4_mfn, INVALID_MFN) )
         return state;
 
     state.cr3 = read_cr3();
@@ -111,7 +111,7 @@ struct efi_rs_state efi_rs_enter(void)
         lgdt(&gdt_desc);
     }
 
-    switch_cr3_cr4(virt_to_maddr(efi_l4_pgtable), read_cr4());
+    switch_cr3_cr4(mfn_to_maddr(efi_l4_mfn), read_cr4());
 
     return state;
 }
@@ -140,9 +140,9 @@ void efi_rs_leave(struct efi_rs_state *state)
 
 bool efi_rs_using_pgtables(void)
 {
-    return efi_l4_pgtable &&
+    return !mfn_eq(efi_l4_mfn, INVALID_MFN) &&
            (smp_processor_id() == efi_rs_on_cpu) &&
-           (read_cr3() == virt_to_maddr(efi_l4_pgtable));
+           (read_cr3() == mfn_to_maddr(efi_l4_mfn));
 }
 
 unsigned long efi_get_time(void)
-- 
2.11.0


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