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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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134
grub-core/lib/x86_64/xen/relocator.S
View file

@ -16,95 +16,85 @@
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/x86_64/memory.h>
#include <grub/x86_64/types.h>
#include <grub/symbol.h>
#include <grub/xen.h>
/* Macro to load an imm64 value stored by the C-part into %rax: */
#define MOV_IMM64_RAX(var) .byte 0x48, 0xb8; VARIABLE(var); .quad 0
.p2align 4 /* force 16-byte alignment */
VARIABLE(grub_relocator_xen_remap_start)
LOCAL(base):
/* mov imm64, %rax */
.byte 0x48
.byte 0xb8
VARIABLE(grub_relocator_xen_remapper_virt)
.quad 0
/* Remap the remapper to it's new address. */
MOV_IMM64_RAX(grub_relocator_xen_remapper_virt)
movq %rax, %rdi
movq %rax, %rbx
movq %rax, %rdi /* %rdi: new virtual address of remapper */
movq %rax, %rbx /* Remember new virtual address */
/* mov imm64, %rax */
.byte 0x48
.byte 0xb8
VARIABLE(grub_relocator_xen_remapper_map)
.quad 0
MOV_IMM64_RAX(grub_relocator_xen_remapper_map)
movq %rax, %rsi
movq %rax, %rsi /* %rsi: page table entry */
movq $2, %rdx
movq $UVMF_INVLPG, %rdx /* %rdx: flags (inv. single entry) */
movq $__HYPERVISOR_update_va_mapping, %rax
syscall
syscall /* Do the remap operation */
addq $(LOCAL(cont) - LOCAL(base)), %rbx
jmp *%rbx
jmp *%rbx /* Continue with new virtual address */
LOCAL(cont):
/* mov imm64, %rcx */
.byte 0x48
.byte 0xb9
VARIABLE(grub_relocator_xen_paging_size)
.quad 0
/* Modify mappings of new page tables to be read-only. */
MOV_IMM64_RAX(grub_relocator_xen_mfn_list)
/* mov imm64, %rax */
.byte 0x48
.byte 0xb8
VARIABLE(grub_relocator_xen_paging_start)
.quad 0
movq %rax, %rbx /* %rbx is the base of the p2m list */
leaq EXT_C(grub_relocator_xen_paging_areas) (%rip), %r8
movq %rax, %r12
/* mov imm64, %rax */
.byte 0x48
.byte 0xb8
VARIABLE(grub_relocator_xen_mfn_list)
.quad 0
movq %rax, %rsi
1:
movq 0(%r8), %r12 /* Get start pfn of the current area */
movq GRUB_TARGET_SIZEOF_LONG(%r8), %rcx /* Get # of pg tables */
testq %rcx, %rcx /* 0 -> last area reached */
jz 3f
2:
movq %r12, %rdi
movq %rsi, %rbx
movq 0(%rsi), %rsi
shlq $12, %rsi
orq $5, %rsi
movq $2, %rdx
movq %rcx, %r9
shlq $PAGE_SHIFT, %rdi /* virtual address (1:1 mapping) */
movq (%rbx, %r12, 8), %rsi /* mfn */
shlq $PAGE_SHIFT, %rsi
orq $(GRUB_PAGE_PRESENT | GRUB_PAGE_USER), %rsi /* Build pte */
movq $UVMF_INVLPG, %rdx
movq %rcx, %r9 /* %rcx clobbered by hypercall */
movq $__HYPERVISOR_update_va_mapping, %rax
syscall
movq %r9, %rcx
addq $8, %rbx
addq $4096, %r12
movq %rbx, %rsi
incq %r12 /* next pfn */
loop 1b
loop 2b
leaq LOCAL(mmu_op) (%rip), %rdi
movq $3, %rsi
movq $0, %rdx
movq $0x7FF0, %r10
addq $(2 * GRUB_TARGET_SIZEOF_LONG), %r8 /* next pg table area */
jmp 1b
3:
/* Switch page tables: pin new L4 pt, load cr3, unpin old L4. */
leaq EXT_C(grub_relocator_xen_mmu_op) (%rip), %rdi
movq $3, %rsi /* 3 mmu ops */
movq $0, %rdx /* pdone (not used) */
movq $DOMID_SELF, %r10
movq $__HYPERVISOR_mmuext_op, %rax
syscall
/* mov imm64, %rax */
.byte 0x48
.byte 0xb8
VARIABLE(grub_relocator_xen_remap_continue)
.quad 0
/* Continue in virtual kernel mapping. */
MOV_IMM64_RAX(grub_relocator_xen_remap_continue)
jmp *%rax
LOCAL(mmu_op):
VARIABLE(grub_relocator_xen_paging_areas)
/* array of start, size pairs, size 0 is end marker */
.quad 0, 0, 0, 0, 0, 0, 0, 0
VARIABLE(grub_relocator_xen_mmu_op)
.space 256
@ -112,46 +102,32 @@ VARIABLE(grub_relocator_xen_remap_end)
VARIABLE(grub_relocator_xen_start)
/* mov imm64, %rax */
.byte 0x48
.byte 0xb8
VARIABLE(grub_relocator_xen_remapper_virt2)
.quad 0
/* Unmap old remapper area. */
MOV_IMM64_RAX(grub_relocator_xen_remapper_virt2)
movq %rax, %rdi
xorq %rax, %rax
xorq %rax, %rax /* Invalid pte */
movq %rax, %rsi
movq $2, %rdx
movq $UVMF_INVLPG, %rdx
movq $__HYPERVISOR_update_va_mapping, %rax
syscall
/* mov imm64, %rax */
.byte 0x48
.byte 0xb8
VARIABLE(grub_relocator_xen_stack)
.quad 0
/* Prepare registers for starting kernel. */
MOV_IMM64_RAX(grub_relocator_xen_stack)
movq %rax, %rsp
/* mov imm64, %rax */
.byte 0x48
.byte 0xb8
VARIABLE(grub_relocator_xen_start_info)
.quad 0
MOV_IMM64_RAX(grub_relocator_xen_start_info)
movq %rax, %rsi
cld
/* mov imm64, %rax */
.byte 0x48
.byte 0xb8
VARIABLE(grub_relocator_xen_entry_point)
.quad 0
MOV_IMM64_RAX(grub_relocator_xen_entry_point)
/* Now start the new kernel. */
jmp *%rax
VARIABLE(grub_relocator_xen_end)