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-rw-r--r--drivers/lguest/x86/core.c724
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diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c
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--- a/drivers/lguest/x86/core.c
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@@ -1,724 +0,0 @@
-/*
- * Copyright (C) 2006, Rusty Russell <rusty@rustcorp.com.au> IBM Corporation.
- * Copyright (C) 2007, Jes Sorensen <jes@sgi.com> SGI.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
- * NON INFRINGEMENT. See the GNU General Public License for more
- * details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
-/*P:450
- * This file contains the x86-specific lguest code. It used to be all
- * mixed in with drivers/lguest/core.c but several foolhardy code slashers
- * wrestled most of the dependencies out to here in preparation for porting
- * lguest to other architectures (see what I mean by foolhardy?).
- *
- * This also contains a couple of non-obvious setup and teardown pieces which
- * were implemented after days of debugging pain.
-:*/
-#include <linux/kernel.h>
-#include <linux/start_kernel.h>
-#include <linux/string.h>
-#include <linux/console.h>
-#include <linux/screen_info.h>
-#include <linux/irq.h>
-#include <linux/interrupt.h>
-#include <linux/clocksource.h>
-#include <linux/clockchips.h>
-#include <linux/cpu.h>
-#include <linux/lguest.h>
-#include <linux/lguest_launcher.h>
-#include <asm/paravirt.h>
-#include <asm/param.h>
-#include <asm/page.h>
-#include <asm/pgtable.h>
-#include <asm/desc.h>
-#include <asm/setup.h>
-#include <asm/lguest.h>
-#include <linux/uaccess.h>
-#include <asm/fpu/internal.h>
-#include <asm/tlbflush.h>
-#include "../lg.h"
-
-static int cpu_had_pge;
-
-static struct {
- unsigned long offset;
- unsigned short segment;
-} lguest_entry;
-
-/* Offset from where switcher.S was compiled to where we've copied it */
-static unsigned long switcher_offset(void)
-{
- return switcher_addr - (unsigned long)start_switcher_text;
-}
-
-/* This cpu's struct lguest_pages (after the Switcher text page) */
-static struct lguest_pages *lguest_pages(unsigned int cpu)
-{
- return &(((struct lguest_pages *)(switcher_addr + PAGE_SIZE))[cpu]);
-}
-
-static DEFINE_PER_CPU(struct lg_cpu *, lg_last_cpu);
-
-/*S:010
- * We approach the Switcher.
- *
- * Remember that each CPU has two pages which are visible to the Guest when it
- * runs on that CPU. This has to contain the state for that Guest: we copy the
- * state in just before we run the Guest.
- *
- * Each Guest has "changed" flags which indicate what has changed in the Guest
- * since it last ran. We saw this set in interrupts_and_traps.c and
- * segments.c.
- */
-static void copy_in_guest_info(struct lg_cpu *cpu, struct lguest_pages *pages)
-{
- /*
- * Copying all this data can be quite expensive. We usually run the
- * same Guest we ran last time (and that Guest hasn't run anywhere else
- * meanwhile). If that's not the case, we pretend everything in the
- * Guest has changed.
- */
- if (__this_cpu_read(lg_last_cpu) != cpu || cpu->last_pages != pages) {
- __this_cpu_write(lg_last_cpu, cpu);
- cpu->last_pages = pages;
- cpu->changed = CHANGED_ALL;
- }
-
- /*
- * These copies are pretty cheap, so we do them unconditionally: */
- /* Save the current Host top-level page directory.
- */
- pages->state.host_cr3 = __pa(current->mm->pgd);
- /*
- * Set up the Guest's page tables to see this CPU's pages (and no
- * other CPU's pages).
- */
- map_switcher_in_guest(cpu, pages);
- /*
- * Set up the two "TSS" members which tell the CPU what stack to use
- * for traps which do directly into the Guest (ie. traps at privilege
- * level 1).
- */
- pages->state.guest_tss.sp1 = cpu->esp1;
- pages->state.guest_tss.ss1 = cpu->ss1;
-
- /* Copy direct-to-Guest trap entries. */
- if (cpu->changed & CHANGED_IDT)
- copy_traps(cpu, pages->state.guest_idt, default_idt_entries);
-
- /* Copy all GDT entries which the Guest can change. */
- if (cpu->changed & CHANGED_GDT)
- copy_gdt(cpu, pages->state.guest_gdt);
- /* If only the TLS entries have changed, copy them. */
- else if (cpu->changed & CHANGED_GDT_TLS)
- copy_gdt_tls(cpu, pages->state.guest_gdt);
-
- /* Mark the Guest as unchanged for next time. */
- cpu->changed = 0;
-}
-
-/* Finally: the code to actually call into the Switcher to run the Guest. */
-static void run_guest_once(struct lg_cpu *cpu, struct lguest_pages *pages)
-{
- /* This is a dummy value we need for GCC's sake. */
- unsigned int clobber;
-
- /*
- * Copy the guest-specific information into this CPU's "struct
- * lguest_pages".
- */
- copy_in_guest_info(cpu, pages);
-
- /*
- * Set the trap number to 256 (impossible value). If we fault while
- * switching to the Guest (bad segment registers or bug), this will
- * cause us to abort the Guest.
- */
- cpu->regs->trapnum = 256;
-
- /*
- * Now: we push the "eflags" register on the stack, then do an "lcall".
- * This is how we change from using the kernel code segment to using
- * the dedicated lguest code segment, as well as jumping into the
- * Switcher.
- *
- * The lcall also pushes the old code segment (KERNEL_CS) onto the
- * stack, then the address of this call. This stack layout happens to
- * exactly match the stack layout created by an interrupt...
- */
- asm volatile("pushf; lcall *%4"
- /*
- * This is how we tell GCC that %eax ("a") and %ebx ("b")
- * are changed by this routine. The "=" means output.
- */
- : "=a"(clobber), "=b"(clobber)
- /*
- * %eax contains the pages pointer. ("0" refers to the
- * 0-th argument above, ie "a"). %ebx contains the
- * physical address of the Guest's top-level page
- * directory.
- */
- : "0"(pages),
- "1"(__pa(cpu->lg->pgdirs[cpu->cpu_pgd].pgdir)),
- "m"(lguest_entry)
- /*
- * We tell gcc that all these registers could change,
- * which means we don't have to save and restore them in
- * the Switcher.
- */
- : "memory", "%edx", "%ecx", "%edi", "%esi");
-}
-/*:*/
-
-unsigned long *lguest_arch_regptr(struct lg_cpu *cpu, size_t reg_off, bool any)
-{
- switch (reg_off) {
- case offsetof(struct pt_regs, bx):
- return &cpu->regs->ebx;
- case offsetof(struct pt_regs, cx):
- return &cpu->regs->ecx;
- case offsetof(struct pt_regs, dx):
- return &cpu->regs->edx;
- case offsetof(struct pt_regs, si):
- return &cpu->regs->esi;
- case offsetof(struct pt_regs, di):
- return &cpu->regs->edi;
- case offsetof(struct pt_regs, bp):
- return &cpu->regs->ebp;
- case offsetof(struct pt_regs, ax):
- return &cpu->regs->eax;
- case offsetof(struct pt_regs, ip):
- return &cpu->regs->eip;
- case offsetof(struct pt_regs, sp):
- return &cpu->regs->esp;
- }
-
- /* Launcher can read these, but we don't allow any setting. */
- if (any) {
- switch (reg_off) {
- case offsetof(struct pt_regs, ds):
- return &cpu->regs->ds;
- case offsetof(struct pt_regs, es):
- return &cpu->regs->es;
- case offsetof(struct pt_regs, fs):
- return &cpu->regs->fs;
- case offsetof(struct pt_regs, gs):
- return &cpu->regs->gs;
- case offsetof(struct pt_regs, cs):
- return &cpu->regs->cs;
- case offsetof(struct pt_regs, flags):
- return &cpu->regs->eflags;
- case offsetof(struct pt_regs, ss):
- return &cpu->regs->ss;
- }
- }
-
- return NULL;
-}
-
-/*M:002
- * There are hooks in the scheduler which we can register to tell when we
- * get kicked off the CPU (preempt_notifier_register()). This would allow us
- * to lazily disable SYSENTER which would regain some performance, and should
- * also simplify copy_in_guest_info(). Note that we'd still need to restore
- * things when we exit to Launcher userspace, but that's fairly easy.
- *
- * We could also try using these hooks for PGE, but that might be too expensive.
- *
- * The hooks were designed for KVM, but we can also put them to good use.
-:*/
-
-/*H:040
- * This is the i386-specific code to setup and run the Guest. Interrupts
- * are disabled: we own the CPU.
- */
-void lguest_arch_run_guest(struct lg_cpu *cpu)
-{
- /*
- * SYSENTER is an optimized way of doing system calls. We can't allow
- * it because it always jumps to privilege level 0. A normal Guest
- * won't try it because we don't advertise it in CPUID, but a malicious
- * Guest (or malicious Guest userspace program) could, so we tell the
- * CPU to disable it before running the Guest.
- */
- if (boot_cpu_has(X86_FEATURE_SEP))
- wrmsr(MSR_IA32_SYSENTER_CS, 0, 0);
-
- /*
- * Now we actually run the Guest. It will return when something
- * interesting happens, and we can examine its registers to see what it
- * was doing.
- */
- run_guest_once(cpu, lguest_pages(raw_smp_processor_id()));
-
- /*
- * Note that the "regs" structure contains two extra entries which are
- * not really registers: a trap number which says what interrupt or
- * trap made the switcher code come back, and an error code which some
- * traps set.
- */
-
- /* Restore SYSENTER if it's supposed to be on. */
- if (boot_cpu_has(X86_FEATURE_SEP))
- wrmsr(MSR_IA32_SYSENTER_CS, __KERNEL_CS, 0);
-
- /*
- * If the Guest page faulted, then the cr2 register will tell us the
- * bad virtual address. We have to grab this now, because once we
- * re-enable interrupts an interrupt could fault and thus overwrite
- * cr2, or we could even move off to a different CPU.
- */
- if (cpu->regs->trapnum == 14)
- cpu->arch.last_pagefault = read_cr2();
- /*
- * Similarly, if we took a trap because the Guest used the FPU,
- * we have to restore the FPU it expects to see.
- * fpu__restore() may sleep and we may even move off to
- * a different CPU. So all the critical stuff should be done
- * before this.
- */
- else if (cpu->regs->trapnum == 7 && !fpregs_active())
- fpu__restore(&current->thread.fpu);
-}
-
-/*H:130
- * Now we've examined the hypercall code; our Guest can make requests.
- * Our Guest is usually so well behaved; it never tries to do things it isn't
- * allowed to, and uses hypercalls instead. Unfortunately, Linux's paravirtual
- * infrastructure isn't quite complete, because it doesn't contain replacements
- * for the Intel I/O instructions. As a result, the Guest sometimes fumbles
- * across one during the boot process as it probes for various things which are
- * usually attached to a PC.
- *
- * When the Guest uses one of these instructions, we get a trap (General
- * Protection Fault) and come here. We queue this to be sent out to the
- * Launcher to handle.
- */
-
-/*
- * The eip contains the *virtual* address of the Guest's instruction:
- * we copy the instruction here so the Launcher doesn't have to walk
- * the page tables to decode it. We handle the case (eg. in a kernel
- * module) where the instruction is over two pages, and the pages are
- * virtually but not physically contiguous.
- *
- * The longest possible x86 instruction is 15 bytes, but we don't handle
- * anything that strange.
- */
-static void copy_from_guest(struct lg_cpu *cpu,
- void *dst, unsigned long vaddr, size_t len)
-{
- size_t to_page_end = PAGE_SIZE - (vaddr % PAGE_SIZE);
- unsigned long paddr;
-
- BUG_ON(len > PAGE_SIZE);
-
- /* If it goes over a page, copy in two parts. */
- if (len > to_page_end) {
- /* But make sure the next page is mapped! */
- if (__guest_pa(cpu, vaddr + to_page_end, &paddr))
- copy_from_guest(cpu, dst + to_page_end,
- vaddr + to_page_end,
- len - to_page_end);
- else
- /* Otherwise fill with zeroes. */
- memset(dst + to_page_end, 0, len - to_page_end);
- len = to_page_end;
- }
-
- /* This will kill the guest if it isn't mapped, but that
- * shouldn't happen. */
- __lgread(cpu, dst, guest_pa(cpu, vaddr), len);
-}
-
-
-static void setup_emulate_insn(struct lg_cpu *cpu)
-{
- cpu->pending.trap = 13;
- copy_from_guest(cpu, cpu->pending.insn, cpu->regs->eip,
- sizeof(cpu->pending.insn));
-}
-
-static void setup_iomem_insn(struct lg_cpu *cpu, unsigned long iomem_addr)
-{
- cpu->pending.trap = 14;
- cpu->pending.addr = iomem_addr;
- copy_from_guest(cpu, cpu->pending.insn, cpu->regs->eip,
- sizeof(cpu->pending.insn));
-}
-
-/*H:050 Once we've re-enabled interrupts, we look at why the Guest exited. */
-void lguest_arch_handle_trap(struct lg_cpu *cpu)
-{
- unsigned long iomem_addr;
-
- switch (cpu->regs->trapnum) {
- case 13: /* We've intercepted a General Protection Fault. */
- /* Hand to Launcher to emulate those pesky IN and OUT insns */
- if (cpu->regs->errcode == 0) {
- setup_emulate_insn(cpu);
- return;
- }
- break;
- case 14: /* We've intercepted a Page Fault. */
- /*
- * The Guest accessed a virtual address that wasn't mapped.
- * This happens a lot: we don't actually set up most of the page
- * tables for the Guest at all when we start: as it runs it asks
- * for more and more, and we set them up as required. In this
- * case, we don't even tell the Guest that the fault happened.
- *
- * The errcode tells whether this was a read or a write, and
- * whether kernel or userspace code.
- */
- if (demand_page(cpu, cpu->arch.last_pagefault,
- cpu->regs->errcode, &iomem_addr))
- return;
-
- /* Was this an access to memory mapped IO? */
- if (iomem_addr) {
- /* Tell Launcher, let it handle it. */
- setup_iomem_insn(cpu, iomem_addr);
- return;
- }
-
- /*
- * OK, it's really not there (or not OK): the Guest needs to
- * know. We write out the cr2 value so it knows where the
- * fault occurred.
- *
- * Note that if the Guest were really messed up, this could
- * happen before it's done the LHCALL_LGUEST_INIT hypercall, so
- * lg->lguest_data could be NULL
- */
- if (cpu->lg->lguest_data &&
- put_user(cpu->arch.last_pagefault,
- &cpu->lg->lguest_data->cr2))
- kill_guest(cpu, "Writing cr2");
- break;
- case 7: /* We've intercepted a Device Not Available fault. */
- /* No special handling is needed here. */
- break;
- case 32 ... 255:
- /* This might be a syscall. */
- if (could_be_syscall(cpu->regs->trapnum))
- break;
-
- /*
- * Other values mean a real interrupt occurred, in which case
- * the Host handler has already been run. We just do a
- * friendly check if another process should now be run, then
- * return to run the Guest again.
- */
- cond_resched();
- return;
- case LGUEST_TRAP_ENTRY:
- /*
- * Our 'struct hcall_args' maps directly over our regs: we set
- * up the pointer now to indicate a hypercall is pending.
- */
- cpu->hcall = (struct hcall_args *)cpu->regs;
- return;
- }
-
- /* We didn't handle the trap, so it needs to go to the Guest. */
- if (!deliver_trap(cpu, cpu->regs->trapnum))
- /*
- * If the Guest doesn't have a handler (either it hasn't
- * registered any yet, or it's one of the faults we don't let
- * it handle), it dies with this cryptic error message.
- */
- kill_guest(cpu, "unhandled trap %li at %#lx (%#lx)",
- cpu->regs->trapnum, cpu->regs->eip,
- cpu->regs->trapnum == 14 ? cpu->arch.last_pagefault
- : cpu->regs->errcode);
-}
-
-/*
- * Now we can look at each of the routines this calls, in increasing order of
- * complexity: do_hypercalls(), emulate_insn(), maybe_do_interrupt(),
- * deliver_trap() and demand_page(). After all those, we'll be ready to
- * examine the Switcher, and our philosophical understanding of the Host/Guest
- * duality will be complete.
-:*/
-static void adjust_pge(void *on)
-{
- if (on)
- cr4_set_bits(X86_CR4_PGE);
- else
- cr4_clear_bits(X86_CR4_PGE);
-}
-
-/*H:020
- * Now the Switcher is mapped and every thing else is ready, we need to do
- * some more i386-specific initialization.
- */
-void __init lguest_arch_host_init(void)
-{
- int i;
-
- /*
- * Most of the x86/switcher_32.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
- * compiled-in 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 neater. */
- 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_rw(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.sp0 = (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_rw(i)[GDT_ENTRY_LGUEST_CS] = FULL_EXEC_SEGMENT;
- get_cpu_gdt_rw(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;
-
- /*
- * Finally, we need to turn off "Page Global Enable". PGE is an
- * optimization where page table entries are specially marked to show
- * they never change. The Host kernel marks all the kernel pages this
- * way because it's always present, even when userspace is running.
- *
- * Lguest breaks this: unbeknownst to the rest of the Host kernel, we
- * switch to the Guest kernel. If you don't disable this on all CPUs,
- * you'll get really weird bugs that you'll chase for two days.
- *
- * I used to turn PGE off every time we switched to the Guest and back
- * on when we return, but that slowed the Switcher down noticibly.
- */
-
- /*
- * We don't need the complexity of CPUs coming and going while we're
- * doing this.
- */
- get_online_cpus();
- if (boot_cpu_has(X86_FEATURE_PGE)) { /* We have a broader idea of "global". */
- /* Remember that this was originally set (for cleanup). */
- cpu_had_pge = 1;
- /*
- * adjust_pge is a helper function which sets or unsets the PGE
- * bit on its CPU, depending on the argument (0 == unset).
- */
- on_each_cpu(adjust_pge, (void *)0, 1);
- /* Turn off the feature in the global feature set. */
- clear_cpu_cap(&boot_cpu_data, X86_FEATURE_PGE);
- }
- put_online_cpus();
-}
-/*:*/
-
-void __exit lguest_arch_host_fini(void)
-{
- /* If we had PGE before we started, turn it back on now. */
- get_online_cpus();
- if (cpu_had_pge) {
- set_cpu_cap(&boot_cpu_data, X86_FEATURE_PGE);
- /* adjust_pge's argument "1" means set PGE. */
- on_each_cpu(adjust_pge, (void *)1, 1);
- }
- put_online_cpus();
-}
-
-
-/*H:122 The i386-specific hypercalls simply farm out to the right functions. */
-int lguest_arch_do_hcall(struct lg_cpu *cpu, struct hcall_args *args)
-{
- switch (args->arg0) {
- case LHCALL_LOAD_GDT_ENTRY:
- load_guest_gdt_entry(cpu, args->arg1, args->arg2, args->arg3);
- break;
- case LHCALL_LOAD_IDT_ENTRY:
- load_guest_idt_entry(cpu, args->arg1, args->arg2, args->arg3);
- break;
- case LHCALL_LOAD_TLS:
- guest_load_tls(cpu, args->arg1);
- break;
- default:
- /* Bad Guest. Bad! */
- return -EIO;
- }
- return 0;
-}
-
-/*H:126 i386-specific hypercall initialization: */
-int lguest_arch_init_hypercalls(struct lg_cpu *cpu)
-{
- u32 tsc_speed;
-
- /*
- * The pointer to the Guest's "struct lguest_data" is the only argument.
- * We check that address now.
- */
- if (!lguest_address_ok(cpu->lg, cpu->hcall->arg1,
- sizeof(*cpu->lg->lguest_data)))
- return -EFAULT;
-
- /*
- * Having checked it, we simply set lg->lguest_data to point straight
- * into the Launcher's memory at the right place and then use
- * copy_to_user/from_user from now on, instead of lgread/write. I put
- * this in to show that I'm not immune to writing stupid
- * optimizations.
- */
- cpu->lg->lguest_data = cpu->lg->mem_base + cpu->hcall->arg1;
-
- /*
- * We insist that the Time Stamp Counter exist and doesn't change with
- * cpu frequency. Some devious chip manufacturers decided that TSC
- * changes could be handled in software. I decided that time going
- * backwards might be good for benchmarks, but it's bad for users.
- *
- * We also insist that the TSC be stable: the kernel detects unreliable
- * TSCs for its own purposes, and we use that here.
- */
- if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) && !check_tsc_unstable())
- tsc_speed = tsc_khz;
- else
- tsc_speed = 0;
- if (put_user(tsc_speed, &cpu->lg->lguest_data->tsc_khz))
- return -EFAULT;
-
- /* The interrupt code might not like the system call vector. */
- if (!check_syscall_vector(cpu->lg))
- kill_guest(cpu, "bad syscall vector");
-
- return 0;
-}
-/*:*/
-
-/*L:030
- * Most of the Guest's registers are left alone: we used get_zeroed_page() to
- * allocate the structure, so they will be 0.
- */
-void lguest_arch_setup_regs(struct lg_cpu *cpu, unsigned long start)
-{
- struct lguest_regs *regs = cpu->regs;
-
- /*
- * There are four "segment" registers which the Guest needs to boot:
- * The "code segment" register (cs) refers to the kernel code segment
- * __KERNEL_CS, and the "data", "extra" and "stack" segment registers
- * refer to the kernel data segment __KERNEL_DS.
- *
- * The privilege level is packed into the lower bits. The Guest runs
- * at privilege level 1 (GUEST_PL).
- */
- regs->ds = regs->es = regs->ss = __KERNEL_DS|GUEST_PL;
- regs->cs = __KERNEL_CS|GUEST_PL;
-
- /*
- * The "eflags" register contains miscellaneous flags. Bit 1 (0x002)
- * is supposed to always be "1". Bit 9 (0x200) controls whether
- * interrupts are enabled. We always leave interrupts enabled while
- * running the Guest.
- */
- regs->eflags = X86_EFLAGS_IF | X86_EFLAGS_FIXED;
-
- /*
- * The "Extended Instruction Pointer" register says where the Guest is
- * running.
- */
- regs->eip = start;
-
- /*
- * %esi points to our boot information, at physical address 0, so don't
- * touch it.
- */
-
- /* There are a couple of GDT entries the Guest expects at boot. */
- setup_guest_gdt(cpu);
-}