lguest: fix on Intel when KVM loaded (unhandled trap 13)

[sfrench/cifs-2.6.git] / drivers / lguest / x86 / core.c

diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c
index a6b717644be0d50efc2f257e52e9e543cc545833..eaf722fe309a2919de7cd3488b452b7604d94546 100644 (file)
--- a/drivers/lguest/x86/core.c
+++ b/drivers/lguest/x86/core.c
@@ -324,6 +324,11 @@ static void rewrite_hypercall(struct lg_cpu *cpu)
        u8 insn[3] = {0xcd, 0x1f, 0x90};
 
        __lgwrite(cpu, guest_pa(cpu, cpu->regs->eip), insn, sizeof(insn));
+       /* The above write might have caused a copy of that page to be made
+        * (if it was read-only).  We need to make sure the Guest has
+        * up-to-date pagetables.  As this doesn't happen often, we can just
+        * drop them all. */
+       guest_pagetable_clear_all(cpu);
 }
 
 static bool is_hypercall(struct lg_cpu *cpu)
@@ -353,6 +358,16 @@ void lguest_arch_handle_trap(struct lg_cpu *cpu)
                        if (emulate_insn(cpu))
                                return;
                }
+               /* If KVM is active, the vmcall instruction triggers a
+                * General Protection Fault.  Normally it triggers an
+                * invalid opcode fault (6): */
+       case 6:
+               /* We need to check if ring == GUEST_PL and
+                * faulting instruction == vmcall. */
+               if (is_hypercall(cpu)) {
+                       rewrite_hypercall(cpu);
+                       return;
+               }
                break;
        case 14: /* We've intercepted a Page Fault. */
                /* The Guest accessed a virtual address that wasn't mapped.
@@ -398,15 +413,6 @@ void lguest_arch_handle_trap(struct lg_cpu *cpu)
                 * up the pointer now to indicate a hypercall is pending. */
                cpu->hcall = (struct hcall_args *)cpu->regs;
                return;
-       case 6:
-               /* kvm hypercalls trigger an invalid opcode fault (6).
-                * We need to check if ring == GUEST_PL and
-                * faulting instruction == vmcall. */
-               if (is_hypercall(cpu)) {
-                       rewrite_hypercall(cpu);
-                       return;
-               }
-               break;
        }
 
        /* We didn't handle the trap, so it needs to go to the Guest. */
@@ -563,8 +569,8 @@ void __exit lguest_arch_host_fini(void)
 int lguest_arch_do_hcall(struct lg_cpu *cpu, struct hcall_args *args)
 {
        switch (args->arg0) {
-       case LHCALL_LOAD_GDT:
-               load_guest_gdt(cpu, args->arg1, args->arg2);
+       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);