- /* Most of the switcher.S doesn't care that it's been moved; on Intel,
- * jumps are relative, and it doesn't access any references to external
- * code or data.
- *
- * The only exception is the interrupt handlers in switcher.S: their
- * addresses are placed in a table (default_idt_entries), so we need to
- * update the table with the new addresses. switcher_offset() is a
- * convenience function which returns the distance between the builtin
- * switcher code and the high-mapped copy we just made. */
- for (i = 0; i < IDT_ENTRIES; i++)
- default_idt_entries[i] += switcher_offset();
-
- /*
- * Set up the Switcher's per-cpu areas.
- *
- * Each CPU gets two pages of its own within the high-mapped region
- * (aka. "struct lguest_pages"). Much of this can be initialized now,
- * but some depends on what Guest we are running (which is set up in
- * copy_in_guest_info()).
- */
- for_each_possible_cpu(i) {
- /* lguest_pages() returns this CPU's two pages. */
- struct lguest_pages *pages = lguest_pages(i);
- /* This is a convenience pointer to make the code fit one
- * statement to a line. */
- struct lguest_ro_state *state = &pages->state;
-
- /* The Global Descriptor Table: the Host has a different one
- * for each CPU. We keep a descriptor for the GDT which says
- * where it is and how big it is (the size is actually the last
- * byte, not the size, hence the "-1"). */
- state->host_gdt_desc.size = GDT_SIZE-1;
- state->host_gdt_desc.address = (long)get_cpu_gdt_table(i);
-
- /* All CPUs on the Host use the same Interrupt Descriptor
- * Table, so we just use store_idt(), which gets this CPU's IDT
- * descriptor. */
- store_idt(&state->host_idt_desc);
-
- /* The descriptors for the Guest's GDT and IDT can be filled
- * out now, too. We copy the GDT & IDT into ->guest_gdt and
- * ->guest_idt before actually running the Guest. */
- state->guest_idt_desc.size = sizeof(state->guest_idt)-1;
- state->guest_idt_desc.address = (long)&state->guest_idt;
- state->guest_gdt_desc.size = sizeof(state->guest_gdt)-1;
- state->guest_gdt_desc.address = (long)&state->guest_gdt;
-
- /* We know where we want the stack to be when the Guest enters
- * the switcher: in pages->regs. The stack grows upwards, so
- * we start it at the end of that structure. */
- state->guest_tss.esp0 = (long)(&pages->regs + 1);
- /* And this is the GDT entry to use for the stack: we keep a
- * couple of special LGUEST entries. */
- state->guest_tss.ss0 = LGUEST_DS;
-
- /* x86 can have a finegrained bitmap which indicates what I/O
- * ports the process can use. We set it to the end of our
- * structure, meaning "none". */
- state->guest_tss.io_bitmap_base = sizeof(state->guest_tss);
-
- /* Some GDT entries are the same across all Guests, so we can
- * set them up now. */
- setup_default_gdt_entries(state);
- /* Most IDT entries are the same for all Guests, too.*/
- setup_default_idt_entries(state, default_idt_entries);
-
- /* The Host needs to be able to use the LGUEST segments on this
- * CPU, too, so put them in the Host GDT. */
- get_cpu_gdt_table(i)[GDT_ENTRY_LGUEST_CS] = FULL_EXEC_SEGMENT;
- get_cpu_gdt_table(i)[GDT_ENTRY_LGUEST_DS] = FULL_SEGMENT;
- }
-
- /* In the Switcher, we want the %cs segment register to use the
- * LGUEST_CS GDT entry: we've put that in the Host and Guest GDTs, so
- * it will be undisturbed when we switch. To change %cs and jump we
- * need this structure to feed to Intel's "lcall" instruction. */
- lguest_entry.offset = (long)switch_to_guest + switcher_offset();
- lguest_entry.segment = LGUEST_CS;
-