aboutsummaryrefslogtreecommitdiff
path: root/drivers/lguest
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/lguest')
-rw-r--r--drivers/lguest/lg.h3
-rw-r--r--drivers/lguest/segments.c13
-rw-r--r--drivers/lguest/x86/core.c28
3 files changed, 26 insertions, 18 deletions
diff --git a/drivers/lguest/lg.h b/drivers/lguest/lg.h
index ac8a4a3741b..af92a176697 100644
--- a/drivers/lguest/lg.h
+++ b/drivers/lguest/lg.h
@@ -158,7 +158,8 @@ void free_interrupts(void);
/* segments.c: */
void setup_default_gdt_entries(struct lguest_ro_state *state);
void setup_guest_gdt(struct lg_cpu *cpu);
-void load_guest_gdt(struct lg_cpu *cpu, unsigned long table, u32 num);
+void load_guest_gdt_entry(struct lg_cpu *cpu, unsigned int i,
+ u32 low, u32 hi);
void guest_load_tls(struct lg_cpu *cpu, unsigned long tls_array);
void copy_gdt(const struct lg_cpu *cpu, struct desc_struct *gdt);
void copy_gdt_tls(const struct lg_cpu *cpu, struct desc_struct *gdt);
diff --git a/drivers/lguest/segments.c b/drivers/lguest/segments.c
index 4f15439b7f1..7ede64ffeef 100644
--- a/drivers/lguest/segments.c
+++ b/drivers/lguest/segments.c
@@ -144,18 +144,19 @@ void copy_gdt(const struct lg_cpu *cpu, struct desc_struct *gdt)
gdt[i] = cpu->arch.gdt[i];
}
-/*H:620 This is where the Guest asks us to load a new GDT (LHCALL_LOAD_GDT).
- * We copy it from the Guest and tweak the entries. */
-void load_guest_gdt(struct lg_cpu *cpu, unsigned long table, u32 num)
+/*H:620 This is where the Guest asks us to load a new GDT entry
+ * (LHCALL_LOAD_GDT_ENTRY). We tweak the entry and copy it in. */
+void load_guest_gdt_entry(struct lg_cpu *cpu, u32 num, u32 lo, u32 hi)
{
/* We assume the Guest has the same number of GDT entries as the
* Host, otherwise we'd have to dynamically allocate the Guest GDT. */
if (num > ARRAY_SIZE(cpu->arch.gdt))
kill_guest(cpu, "too many gdt entries %i", num);
- /* We read the whole thing in, then fix it up. */
- __lgread(cpu, cpu->arch.gdt, table, num * sizeof(cpu->arch.gdt[0]));
- fixup_gdt_table(cpu, 0, ARRAY_SIZE(cpu->arch.gdt));
+ /* Set it up, then fix it. */
+ cpu->arch.gdt[num].a = lo;
+ cpu->arch.gdt[num].b = hi;
+ fixup_gdt_table(cpu, num, num+1);
/* Mark that the GDT changed so the core knows it has to copy it again,
* even if the Guest is run on the same CPU. */
cpu->changed |= CHANGED_GDT;
diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c
index a6b717644be..eaf722fe309 100644
--- 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);