Make emulator check that vcpu is allowed to execute IN, INS, OUT, OUTS, CLI, STI.
Signed-off-by: Gleb Natapov <[email protected]> --- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/emulate.c | 18 ++++++++--- arch/x86/kvm/x86.c | 63 +++++++++++++++++++++++++++++++++++---- 3 files changed, 71 insertions(+), 11 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index c07c16f..f9a2f66 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -678,6 +678,7 @@ void kvm_disable_tdp(void); int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3); int complete_pio(struct kvm_vcpu *vcpu); +bool kvm_check_iopl(struct kvm_vcpu *vcpu); struct kvm_memory_slot *gfn_to_memslot_unaliased(struct kvm *kvm, gfn_t gfn); diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index c44b460..aee5cc2 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2227,13 +2227,21 @@ special_insn: c->dst.type = OP_NONE; /* Disable writeback. */ break; case 0xfa: /* cli */ - ctxt->eflags &= ~X86_EFLAGS_IF; - c->dst.type = OP_NONE; /* Disable writeback. */ + if (kvm_check_iopl(ctxt->vcpu)) + kvm_inject_gp(ctxt->vcpu, 0); + else { + ctxt->eflags &= ~X86_EFLAGS_IF; + c->dst.type = OP_NONE; /* Disable writeback. */ + } break; case 0xfb: /* sti */ - toggle_interruptibility(ctxt, X86_SHADOW_INT_STI); - ctxt->eflags |= X86_EFLAGS_IF; - c->dst.type = OP_NONE; /* Disable writeback. */ + if (kvm_check_iopl(ctxt->vcpu)) + kvm_inject_gp(ctxt->vcpu, 0); + else { + toggle_interruptibility(ctxt, X86_SHADOW_INT_STI); + ctxt->eflags |= X86_EFLAGS_IF; + c->dst.type = OP_NONE; /* Disable writeback. */ + } break; case 0xfc: /* cld */ ctxt->eflags &= ~EFLG_DF; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0f4ab8d..3dfc430 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3595,10 +3595,58 @@ static int pio_string_write(struct kvm_vcpu *vcpu) return r; } +bool kvm_check_iopl(struct kvm_vcpu *vcpu) +{ + int iopl; + if (!is_protmode(vcpu)) + return false; + if (kvm_get_rflags(vcpu) & X86_EFLAGS_VM) + return true; + iopl = (kvm_get_rflags(vcpu) & X86_EFLAGS_IOPL) >> IOPL_SHIFT; + return kvm_x86_ops->get_cpl(vcpu) > iopl; +} + +bool kvm_check_io_port_access_allowed(struct kvm_vcpu *vcpu, u16 port, u16 len) +{ + struct kvm_segment tr_seg; + int r; + u16 io_bitmap_ptr; + u8 perm, bit_idx = port & 0x7; + unsigned mask = (1 << len) - 1; + + kvm_get_segment(vcpu, &tr_seg, VCPU_SREG_TR); + if (tr_seg.unusable) + return false; + if (tr_seg.limit < 103) + return false; + r = kvm_read_guest_virt_system(tr_seg.base + 102, &io_bitmap_ptr, 2, + vcpu, NULL); + if (r != X86EMUL_CONTINUE) + return false; + if (io_bitmap_ptr + port/8 >= tr_seg.limit) + return false; + r = kvm_read_guest_virt_system(tr_seg.base + io_bitmap_ptr + port/8, + &perm, 1, vcpu, NULL); + if (r != X86EMUL_CONTINUE) + return false; + if ((perm >> bit_idx) & mask) + return false; + return true; +} + int kvm_emulate_pio(struct kvm_vcpu *vcpu, int in, int size, unsigned port) { unsigned long val; + trace_kvm_pio(!in, port, size, 1); + + if (kvm_check_iopl(vcpu)) { + if (!kvm_check_io_port_access_allowed(vcpu, port, size)) { + kvm_inject_gp(vcpu, 0); + return 1; + } + } + vcpu->run->exit_reason = KVM_EXIT_IO; vcpu->run->io.direction = in ? KVM_EXIT_IO_IN : KVM_EXIT_IO_OUT; vcpu->run->io.size = vcpu->arch.pio.size = size; @@ -3610,9 +3658,6 @@ int kvm_emulate_pio(struct kvm_vcpu *vcpu, int in, int size, unsigned port) vcpu->arch.pio.down = 0; vcpu->arch.pio.rep = 0; - trace_kvm_pio(vcpu->run->io.direction == KVM_EXIT_IO_OUT, port, - size, 1); - val = kvm_register_read(vcpu, VCPU_REGS_RAX); memcpy(vcpu->arch.pio_data, &val, 4); @@ -3631,6 +3676,15 @@ int kvm_emulate_pio_string(struct kvm_vcpu *vcpu, int in, unsigned now, in_page; int ret = 0; + trace_kvm_pio(!in, port, size, count); + + if (kvm_check_iopl(vcpu)) { + if (!kvm_check_io_port_access_allowed(vcpu, port, size)) { + kvm_inject_gp(vcpu, 0); + return 1; + } + } + vcpu->run->exit_reason = KVM_EXIT_IO; vcpu->run->io.direction = in ? KVM_EXIT_IO_IN : KVM_EXIT_IO_OUT; vcpu->run->io.size = vcpu->arch.pio.size = size; @@ -3642,9 +3696,6 @@ int kvm_emulate_pio_string(struct kvm_vcpu *vcpu, int in, vcpu->arch.pio.down = down; vcpu->arch.pio.rep = rep; - trace_kvm_pio(vcpu->run->io.direction == KVM_EXIT_IO_OUT, port, - size, count); - if (!count) { kvm_x86_ops->skip_emulated_instruction(vcpu); return 1; -- 1.6.5 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
