diff options
Diffstat (limited to 'drivers/lguest')
| -rw-r--r-- | drivers/lguest/lg.h | 3 | ||||
| -rw-r--r-- | drivers/lguest/segments.c | 13 | ||||
| -rw-r--r-- | drivers/lguest/x86/core.c | 28 |
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); |