diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/x86_emulate.c | 70 |
1 files changed, 69 insertions, 1 deletions
diff --git a/arch/x86/kvm/x86_emulate.c b/arch/x86/kvm/x86_emulate.c index 4d7256da59d8..7a9bddb3ebd4 100644 --- a/arch/x86/kvm/x86_emulate.c +++ b/arch/x86/kvm/x86_emulate.c @@ -1476,6 +1476,71 @@ emulate_syscall(struct x86_emulate_ctxt *ctxt) return 0; } +static int +emulate_sysenter(struct x86_emulate_ctxt *ctxt) +{ + struct decode_cache *c = &ctxt->decode; + struct kvm_segment cs, ss; + u64 msr_data; + + /* inject #UD if LOCK prefix is used */ + if (c->lock_prefix) + return -1; + + /* inject #GP if in real mode or paging is disabled */ + if (ctxt->mode == X86EMUL_MODE_REAL || + !(ctxt->vcpu->arch.cr0 & X86_CR0_PE)) { + kvm_inject_gp(ctxt->vcpu, 0); + return -1; + } + + /* XXX sysenter/sysexit have not been tested in 64bit mode. + * Therefore, we inject an #UD. + */ + if (ctxt->mode == X86EMUL_MODE_PROT64) + return -1; + + setup_syscalls_segments(ctxt, &cs, &ss); + + kvm_x86_ops->get_msr(ctxt->vcpu, MSR_IA32_SYSENTER_CS, &msr_data); + switch (ctxt->mode) { + case X86EMUL_MODE_PROT32: + if ((msr_data & 0xfffc) == 0x0) { + kvm_inject_gp(ctxt->vcpu, 0); + return -1; + } + break; + case X86EMUL_MODE_PROT64: + if (msr_data == 0x0) { + kvm_inject_gp(ctxt->vcpu, 0); + return -1; + } + break; + } + + ctxt->eflags &= ~(EFLG_VM | EFLG_IF | EFLG_RF); + cs.selector = (u16)msr_data; + cs.selector &= ~SELECTOR_RPL_MASK; + ss.selector = cs.selector + 8; + ss.selector &= ~SELECTOR_RPL_MASK; + if (ctxt->mode == X86EMUL_MODE_PROT64 + || is_long_mode(ctxt->vcpu)) { + cs.db = 0; + cs.l = 1; + } + + kvm_x86_ops->set_segment(ctxt->vcpu, &cs, VCPU_SREG_CS); + kvm_x86_ops->set_segment(ctxt->vcpu, &ss, VCPU_SREG_SS); + + kvm_x86_ops->get_msr(ctxt->vcpu, MSR_IA32_SYSENTER_EIP, &msr_data); + c->eip = msr_data; + + kvm_x86_ops->get_msr(ctxt->vcpu, MSR_IA32_SYSENTER_ESP, &msr_data); + c->regs[VCPU_REGS_RSP] = msr_data; + + return 0; +} + int x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) { @@ -2144,7 +2209,10 @@ twobyte_insn: c->dst.type = OP_NONE; break; case 0x34: /* sysenter */ - goto cannot_emulate; + if (emulate_sysenter(ctxt) == -1) + goto cannot_emulate; + else + goto writeback; break; case 0x35: /* sysexit */ goto cannot_emulate; |