@@ -668,6 +668,20 @@ trampoline_setup:
add %esi,sym_fs(__page_tables_start)-8(,%ecx,8)
2: loop 1b
+ /* Map Xen into the higher mappings using 2M superpages. */
+ lea _PAGE_PSE + PAGE_HYPERVISOR_RWX + sym_esi(_start), %eax
+ mov $sym_offs(_start), %ecx /* %eax = PTE to write ^ */
+ mov $sym_offs(_end - 1), %edx
+ shr $L2_PAGETABLE_SHIFT, %ecx /* %ecx = First slot to write */
+ shr $L2_PAGETABLE_SHIFT, %edx /* %edx = Final slot to write */
+
+1: mov %eax, sym_offs(l2_xenmap)(%esi, %ecx, 8)
+ add $1, %ecx
+ add $1 << L2_PAGETABLE_SHIFT, %eax
+
+ cmp %edx, %ecx
+ jbe 1b
+
/*
* Map Xen into the directmap (needed for early-boot pagetable
* handling/walking), and identity map Xen into bootmap (needed for
@@ -43,6 +43,14 @@ multiboot_ptr:
GLOBAL(stack_start)
.quad cpu0_stack + STACK_SIZE - CPUINFO_sizeof
+ .section .bss.page_aligned, "aw", @nobits
+ .align PAGE_SIZE, 0
+
+/* L2 mapping the Xen text/data/bss region. Uses 1x 4k page. */
+GLOBAL(l2_xenmap)
+ .fill L2_PAGETABLE_ENTRIES, 8, 0
+ .size l2_xenmap, . - l2_xenmap
+
.section .data.page_aligned, "aw", @progbits
.align PAGE_SIZE, 0
/*
@@ -80,21 +88,6 @@ GLOBAL(l2_directmap)
.fill 4 * L2_PAGETABLE_ENTRIES - 1, 8, 0
.size l2_directmap, . - l2_directmap
-/*
- * L2 mapping the 1GB Xen text/data/bss region. At boot it maps 16MB from
- * __image_base__, and is modified when Xen relocates itself. Uses 1x 4k
- * page.
- */
-GLOBAL(l2_xenmap)
- .quad 0
- idx = 1
- .rept 7
- .quad sym_offs(__image_base__) + (idx << L2_PAGETABLE_SHIFT) + (PAGE_HYPERVISOR_RWX | _PAGE_PSE)
- idx = idx + 1
- .endr
- .fill L2_PAGETABLE_ENTRIES - 8, 8, 0
- .size l2_xenmap, . - l2_xenmap
-
/* L2 mapping the fixmap. Uses 1x 4k page. */
l2_fixmap:
idx = 0
@@ -585,6 +585,20 @@ static void __init efi_arch_memory_setup(void)
if ( !efi_enabled(EFI_LOADER) )
return;
+ /*
+ * Map Xen into the higher mappings, using 2M superpages.
+ *
+ * NB: We are currently in physical mode, so a RIP-relative relocation
+ * against _start/_end result in our arbitrary placement by the bootloader
+ * in memory, rather than the intended high mappings position. Subtract
+ * xen_phys_start to get the appropriate slots in l2_xenmap[].
+ */
+ for ( i = l2_table_offset((UINTN)_start - xen_phys_start);
+ i <= l2_table_offset((UINTN)_end - 1 - xen_phys_start); ++i )
+ l2_xenmap[i] =
+ l2e_from_paddr(xen_phys_start + (i << L2_PAGETABLE_SHIFT),
+ PAGE_HYPERVISOR_RWX | _PAGE_PSE);
+
/* Check that there is at least 4G of mapping space in l2_*map[] */
BUILD_BUG_ON((sizeof(l2_bootmap) / L2_PAGETABLE_ENTRIES) < 4);
BUILD_BUG_ON((sizeof(l2_directmap) / L2_PAGETABLE_ENTRIES) < 4);
@@ -360,6 +360,9 @@ ASSERT(__2M_rwdata_end <= XEN_VIRT_END - XEN_VIRT_START + __XEN_VIRT_START -
ASSERT(kexec_reloc_size - kexec_reloc <= PAGE_SIZE, "kexec_reloc is too large")
#endif
+/* The Multiboot setup paths relies on this to simplify superpage PTE creation. */
+ASSERT(IS_ALIGNED(_start, MB(2)), "_start misaligned")
+
ASSERT(IS_ALIGNED(__2M_text_end, SECTION_ALIGN), "__2M_text_end misaligned")
ASSERT(IS_ALIGNED(__2M_rodata_start, SECTION_ALIGN), "__2M_rodata_start misaligned")
ASSERT(IS_ALIGNED(__2M_rodata_end, SECTION_ALIGN), "__2M_rodata_end misaligned")
The build-time construction of l2_xenmap[] imposes an arbitrary limit of 16M total, which is a limit looking to be lifted. Move l2_xenmap[] into the BSS, and adjust both the BIOS and EFI paths to fill it in dynamically, based on the final linked size of Xen. Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> --- CC: Jan Beulich <JBeulich@suse.com> CC: Wei Liu <wl@xen.org> CC: Roger Pau Monné <roger.pau@citrix.com> v2: * Rewrite several comments --- xen/arch/x86/boot/head.S | 14 ++++++++++++++ xen/arch/x86/boot/x86_64.S | 23 ++++++++--------------- xen/arch/x86/efi/efi-boot.h | 14 ++++++++++++++ xen/arch/x86/xen.lds.S | 3 +++ 4 files changed, 39 insertions(+), 15 deletions(-)