diff options
Diffstat (limited to 'arch/x86/kvm/emulate.c')
| -rw-r--r-- | arch/x86/kvm/emulate.c | 71 |
1 files changed, 44 insertions, 27 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 50ca1db7247c..7ba4ec77feeb 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -1623,11 +1623,6 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt, goto exception; } - if (!seg_desc.p) { - err_vec = (seg == VCPU_SREG_SS) ? SS_VECTOR : NP_VECTOR; - goto exception; - } - dpl = seg_desc.dpl; switch (seg) { @@ -1643,14 +1638,34 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt, if (!(seg_desc.type & 8)) goto exception; - if (seg_desc.type & 4) { - /* conforming */ - if (dpl > cpl) - goto exception; - } else { - /* nonconforming */ - if (rpl > cpl || dpl != cpl) + if (transfer == X86_TRANSFER_RET) { + /* RET can never return to an inner privilege level. */ + if (rpl < cpl) goto exception; + /* Outer-privilege level return is not implemented */ + if (rpl > cpl) + return X86EMUL_UNHANDLEABLE; + } + if (transfer == X86_TRANSFER_RET || transfer == X86_TRANSFER_TASK_SWITCH) { + if (seg_desc.type & 4) { + /* conforming */ + if (dpl > rpl) + goto exception; + } else { + /* nonconforming */ + if (dpl != rpl) + goto exception; + } + } else { /* X86_TRANSFER_CALL_JMP */ + if (seg_desc.type & 4) { + /* conforming */ + if (dpl > cpl) + goto exception; + } else { + /* nonconforming */ + if (rpl > cpl || dpl != cpl) + goto exception; + } } /* in long-mode d/b must be clear if l is set */ if (seg_desc.d && seg_desc.l) { @@ -1667,6 +1682,10 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt, case VCPU_SREG_TR: if (seg_desc.s || (seg_desc.type != 1 && seg_desc.type != 9)) goto exception; + if (!seg_desc.p) { + err_vec = NP_VECTOR; + goto exception; + } old_desc = seg_desc; seg_desc.type |= 2; /* busy */ ret = ctxt->ops->cmpxchg_emulated(ctxt, desc_addr, &old_desc, &seg_desc, @@ -1691,6 +1710,11 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt, break; } + if (!seg_desc.p) { + err_vec = (seg == VCPU_SREG_SS) ? SS_VECTOR : NP_VECTOR; + goto exception; + } + if (seg_desc.s) { /* mark segment as accessed */ if (!(seg_desc.type & 1)) { @@ -2216,9 +2240,6 @@ static int em_ret_far(struct x86_emulate_ctxt *ctxt) rc = emulate_pop(ctxt, &cs, ctxt->op_bytes); if (rc != X86EMUL_CONTINUE) return rc; - /* Outer-privilege level return is not implemented */ - if (ctxt->mode >= X86EMUL_MODE_PROT16 && (cs & 3) > cpl) - return X86EMUL_UNHANDLEABLE; rc = __load_segment_descriptor(ctxt, (u16)cs, VCPU_SREG_CS, cpl, X86_TRANSFER_RET, &new_desc); @@ -2615,8 +2636,7 @@ emulate_shutdown: } static void -setup_syscalls_segments(struct x86_emulate_ctxt *ctxt, - struct desc_struct *cs, struct desc_struct *ss) +setup_syscalls_segments(struct desc_struct *cs, struct desc_struct *ss) { cs->l = 0; /* will be adjusted later */ set_desc_base(cs, 0); /* flat segment */ @@ -2705,7 +2725,7 @@ static int em_syscall(struct x86_emulate_ctxt *ctxt) if (!(efer & EFER_SCE)) return emulate_ud(ctxt); - setup_syscalls_segments(ctxt, &cs, &ss); + setup_syscalls_segments(&cs, &ss); ops->get_msr(ctxt, MSR_STAR, &msr_data); msr_data >>= 32; cs_sel = (u16)(msr_data & 0xfffc); @@ -2773,7 +2793,7 @@ static int em_sysenter(struct x86_emulate_ctxt *ctxt) if ((msr_data & 0xfffc) == 0x0) return emulate_gp(ctxt, 0); - setup_syscalls_segments(ctxt, &cs, &ss); + setup_syscalls_segments(&cs, &ss); ctxt->eflags &= ~(X86_EFLAGS_VM | X86_EFLAGS_IF); cs_sel = (u16)msr_data & ~SEGMENT_RPL_MASK; ss_sel = cs_sel + 8; @@ -2810,7 +2830,7 @@ static int em_sysexit(struct x86_emulate_ctxt *ctxt) ctxt->mode == X86EMUL_MODE_VM86) return emulate_gp(ctxt, 0); - setup_syscalls_segments(ctxt, &cs, &ss); + setup_syscalls_segments(&cs, &ss); if ((ctxt->rex_prefix & 0x8) != 0x0) usermode = X86EMUL_MODE_PROT64; @@ -3028,8 +3048,7 @@ static int load_state_from_tss16(struct x86_emulate_ctxt *ctxt, return X86EMUL_CONTINUE; } -static int task_switch_16(struct x86_emulate_ctxt *ctxt, - u16 tss_selector, u16 old_tss_sel, +static int task_switch_16(struct x86_emulate_ctxt *ctxt, u16 old_tss_sel, ulong old_tss_base, struct desc_struct *new_desc) { struct tss_segment_16 tss_seg; @@ -3167,8 +3186,7 @@ static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt, return ret; } -static int task_switch_32(struct x86_emulate_ctxt *ctxt, - u16 tss_selector, u16 old_tss_sel, +static int task_switch_32(struct x86_emulate_ctxt *ctxt, u16 old_tss_sel, ulong old_tss_base, struct desc_struct *new_desc) { struct tss_segment_32 tss_seg; @@ -3276,10 +3294,9 @@ static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt, old_tss_sel = 0xffff; if (next_tss_desc.type & 8) - ret = task_switch_32(ctxt, tss_selector, old_tss_sel, - old_tss_base, &next_tss_desc); + ret = task_switch_32(ctxt, old_tss_sel, old_tss_base, &next_tss_desc); else - ret = task_switch_16(ctxt, tss_selector, old_tss_sel, + ret = task_switch_16(ctxt, old_tss_sel, old_tss_base, &next_tss_desc); if (ret != X86EMUL_CONTINUE) return ret; |