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xen: modify page table construction

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Modify the page table construction to allow multiple virtual regions
to be mapped. This is done as preparation for removing the p2m list
from the initial kernel mapping in order to support huge pv domains.

This allows a cleaner approach for mapping the relocator page by
using this capability.

The interface to the assembler level of the relocator has to be changed
in order to be able to process multiple page table areas.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Juergen Gross 2016-03-03 10:38:15 +01:00 • committed by Daniel Kiper
parent 5500cefccd
commit b67a95ecad
6 changed files with 358 additions and 233 deletions
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87
grub-core/lib/i386/xen/relocator.S
View file

@ -16,6 +16,8 @@
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/i386/memory.h>
#include <grub/i386/types.h>
#include <grub/symbol.h>
#include <grub/xen.h>
@ -23,78 +25,86 @@
VARIABLE(grub_relocator_xen_remap_start)
LOCAL(base):
/* mov imm32, %ebx */
/* Remap the remapper to it's new address. */
/* mov imm32, %ebx - %ebx: new virtual address of remapper */
.byte 0xbb
VARIABLE(grub_relocator_xen_remapper_virt)
.long 0
/* mov imm32, %ecx */
/* mov imm32, %ecx - %ecx: low part of page table entry */
.byte 0xb9
VARIABLE(grub_relocator_xen_remapper_map)
.long 0
/* mov imm32, %edx */
/* mov imm32, %edx - %edx: high part of page table entry */
.byte 0xba
VARIABLE(grub_relocator_xen_remapper_map_high)
.long 0
movl %ebx, %ebp
movl %ebx, %ebp /* %ebx is clobbered by hypercall */
movl $2, %esi
movl $UVMF_INVLPG, %esi /* esi: flags (inv. single entry) */
movl $__HYPERVISOR_update_va_mapping, %eax
int $0x82
movl %ebp, %ebx
addl $(LOCAL(cont) - LOCAL(base)), %ebx
jmp *%ebx
jmp *%ebx /* Continue with new virtual address */
LOCAL(cont):
xorl %eax, %eax
movl %eax, %ebp
/* Modify mappings of new page tables to be read-only. */
/* mov imm32, %eax */
.byte 0xb8
VARIABLE(grub_relocator_xen_paging_areas_addr)
.long 0
movl %eax, %ebx
1:
movl 0(%ebx), %ebp /* Get start pfn of the current area */
movl GRUB_TARGET_SIZEOF_LONG(%ebx), %ecx /* Get # of pg tables */
testl %ecx, %ecx /* 0 -> last area reached */
jz 3f
addl $(2 * GRUB_TARGET_SIZEOF_LONG), %ebx
movl %ebx, %esp /* Save current area pointer */
2:
movl %ecx, %edi
/* mov imm32, %eax */
.byte 0xb8
VARIABLE(grub_relocator_xen_mfn_list)
.long 0
movl %eax, %edi
movl %ebp, %eax
movl 0(%edi, %eax, 4), %ecx
/* mov imm32, %ebx */
.byte 0xbb
VARIABLE(grub_relocator_xen_paging_start)
.long 0
shll $12, %eax
addl %eax, %ebx
movl 0(%eax, %ebp, 4), %ecx /* mfn */
movl %ebp, %ebx
shll $PAGE_SHIFT, %ebx /* virtual address (1:1 mapping) */
movl %ecx, %edx
shll $12, %ecx
shrl $20, %edx
orl $5, %ecx
movl $2, %esi
shll $PAGE_SHIFT, %ecx /* prepare pte low part */
shrl $(32 - PAGE_SHIFT), %edx /* pte high part */
orl $(GRUB_PAGE_PRESENT | GRUB_PAGE_USER), %ecx /* pte low */
movl $UVMF_INVLPG, %esi
movl $__HYPERVISOR_update_va_mapping, %eax
int $0x82
int $0x82 /* parameters: eax, ebx, ecx, edx, esi */
incl %ebp
/* mov imm32, %ecx */
.byte 0xb9
VARIABLE(grub_relocator_xen_paging_size)
.long 0
cmpl %ebp, %ecx
incl %ebp /* next pfn */
movl %edi, %ecx
ja 1b
loop 2b
mov %esp, %ebx /* restore area poniter */
jmp 1b
3:
/* Switch page tables: pin new L3 pt, load cr3, unpin old L3. */
/* mov imm32, %ebx */
.byte 0xbb
VARIABLE(grub_relocator_xen_mmu_op_addr)
.long 0
movl $3, %ecx
movl $0, %edx
movl $0x7FF0, %esi
movl $3, %ecx /* 3 mmu ops */
movl $0, %edx /* pdone (not used) */
movl $DOMID_SELF, %esi
movl $__HYPERVISOR_mmuext_op, %eax
int $0x82
/* Continue in virtual kernel mapping. */
/* mov imm32, %eax */
.byte 0xb8
VARIABLE(grub_relocator_xen_remap_continue)
@ -102,6 +112,9 @@ VARIABLE(grub_relocator_xen_remap_continue)
jmp *%eax
VARIABLE(grub_relocator_xen_paging_areas)
.long 0, 0, 0, 0, 0, 0, 0, 0
VARIABLE(grub_relocator_xen_mmu_op)
.space 256
@ -109,6 +122,7 @@ VARIABLE(grub_relocator_xen_remap_end)
VARIABLE(grub_relocator_xen_start)
/* Unmap old remapper area. */
/* mov imm32, %eax */
.byte 0xb8
VARIABLE(grub_relocator_xen_remapper_virt2)
@ -116,14 +130,14 @@ VARIABLE(grub_relocator_xen_remapper_virt2)
movl %eax, %edi
xorl %ecx, %ecx
xorl %ecx, %ecx /* Invalid pte */
xorl %edx, %edx
movl $2, %esi
movl $UVMF_INVLPG, %esi
movl $__HYPERVISOR_update_va_mapping, %eax
int $0x82
/* Prepare registers for starting kernel. */
/* mov imm32, %eax */
.byte 0xb8
VARIABLE(grub_relocator_xen_stack)
@ -145,6 +159,7 @@ VARIABLE(grub_relocator_xen_start_info)
VARIABLE(grub_relocator_xen_entry_point)
.long 0
/* Now start the new kernel. */
jmp *%eax
VARIABLE(grub_relocator_xen_end)