diff options
Diffstat (limited to 'arch/x86/kvm/emulate.c')
| -rw-r--r-- | arch/x86/kvm/emulate.c | 459 |
1 files changed, 76 insertions, 383 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 3b27622d4642..5cc3efa0e21c 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -242,37 +242,6 @@ enum x86_transfer_type { X86_TRANSFER_TASK_SWITCH, }; -static ulong reg_read(struct x86_emulate_ctxt *ctxt, unsigned nr) -{ - if (KVM_EMULATOR_BUG_ON(nr >= NR_EMULATOR_GPRS, ctxt)) - nr &= NR_EMULATOR_GPRS - 1; - - if (!(ctxt->regs_valid & (1 << nr))) { - ctxt->regs_valid |= 1 << nr; - ctxt->_regs[nr] = ctxt->ops->read_gpr(ctxt, nr); - } - return ctxt->_regs[nr]; -} - -static ulong *reg_write(struct x86_emulate_ctxt *ctxt, unsigned nr) -{ - if (KVM_EMULATOR_BUG_ON(nr >= NR_EMULATOR_GPRS, ctxt)) - nr &= NR_EMULATOR_GPRS - 1; - - BUILD_BUG_ON(sizeof(ctxt->regs_dirty) * BITS_PER_BYTE < NR_EMULATOR_GPRS); - BUILD_BUG_ON(sizeof(ctxt->regs_valid) * BITS_PER_BYTE < NR_EMULATOR_GPRS); - - ctxt->regs_valid |= 1 << nr; - ctxt->regs_dirty |= 1 << nr; - return &ctxt->_regs[nr]; -} - -static ulong *reg_rmw(struct x86_emulate_ctxt *ctxt, unsigned nr) -{ - reg_read(ctxt, nr); - return reg_write(ctxt, nr); -} - static void writeback_registers(struct x86_emulate_ctxt *ctxt) { unsigned long dirty = ctxt->regs_dirty; @@ -791,8 +760,7 @@ static int linearize(struct x86_emulate_ctxt *ctxt, ctxt->mode, linear); } -static inline int assign_eip(struct x86_emulate_ctxt *ctxt, ulong dst, - enum x86emul_mode mode) +static inline int assign_eip(struct x86_emulate_ctxt *ctxt, ulong dst) { ulong linear; int rc; @@ -802,41 +770,71 @@ static inline int assign_eip(struct x86_emulate_ctxt *ctxt, ulong dst, if (ctxt->op_bytes != sizeof(unsigned long)) addr.ea = dst & ((1UL << (ctxt->op_bytes << 3)) - 1); - rc = __linearize(ctxt, addr, &max_size, 1, false, true, mode, &linear); + rc = __linearize(ctxt, addr, &max_size, 1, false, true, ctxt->mode, &linear); if (rc == X86EMUL_CONTINUE) ctxt->_eip = addr.ea; return rc; } +static inline int emulator_recalc_and_set_mode(struct x86_emulate_ctxt *ctxt) +{ + u64 efer; + struct desc_struct cs; + u16 selector; + u32 base3; + + ctxt->ops->get_msr(ctxt, MSR_EFER, &efer); + + if (!(ctxt->ops->get_cr(ctxt, 0) & X86_CR0_PE)) { + /* Real mode. cpu must not have long mode active */ + if (efer & EFER_LMA) + return X86EMUL_UNHANDLEABLE; + ctxt->mode = X86EMUL_MODE_REAL; + return X86EMUL_CONTINUE; + } + + if (ctxt->eflags & X86_EFLAGS_VM) { + /* Protected/VM86 mode. cpu must not have long mode active */ + if (efer & EFER_LMA) + return X86EMUL_UNHANDLEABLE; + ctxt->mode = X86EMUL_MODE_VM86; + return X86EMUL_CONTINUE; + } + + if (!ctxt->ops->get_segment(ctxt, &selector, &cs, &base3, VCPU_SREG_CS)) + return X86EMUL_UNHANDLEABLE; + + if (efer & EFER_LMA) { + if (cs.l) { + /* Proper long mode */ + ctxt->mode = X86EMUL_MODE_PROT64; + } else if (cs.d) { + /* 32 bit compatibility mode*/ + ctxt->mode = X86EMUL_MODE_PROT32; + } else { + ctxt->mode = X86EMUL_MODE_PROT16; + } + } else { + /* Legacy 32 bit / 16 bit mode */ + ctxt->mode = cs.d ? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16; + } + + return X86EMUL_CONTINUE; +} + static inline int assign_eip_near(struct x86_emulate_ctxt *ctxt, ulong dst) { - return assign_eip(ctxt, dst, ctxt->mode); + return assign_eip(ctxt, dst); } -static int assign_eip_far(struct x86_emulate_ctxt *ctxt, ulong dst, - const struct desc_struct *cs_desc) +static int assign_eip_far(struct x86_emulate_ctxt *ctxt, ulong dst) { - enum x86emul_mode mode = ctxt->mode; - int rc; + int rc = emulator_recalc_and_set_mode(ctxt); -#ifdef CONFIG_X86_64 - if (ctxt->mode >= X86EMUL_MODE_PROT16) { - if (cs_desc->l) { - u64 efer = 0; + if (rc != X86EMUL_CONTINUE) + return rc; - ctxt->ops->get_msr(ctxt, MSR_EFER, &efer); - if (efer & EFER_LMA) - mode = X86EMUL_MODE_PROT64; - } else - mode = X86EMUL_MODE_PROT32; /* temporary value */ - } -#endif - if (mode == X86EMUL_MODE_PROT16 || mode == X86EMUL_MODE_PROT32) - mode = cs_desc->d ? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16; - rc = assign_eip(ctxt, dst, mode); - if (rc == X86EMUL_CONTINUE) - ctxt->mode = mode; - return rc; + return assign_eip(ctxt, dst); } static inline int jmp_rel(struct x86_emulate_ctxt *ctxt, int rel) @@ -2172,7 +2170,7 @@ static int em_jmp_far(struct x86_emulate_ctxt *ctxt) if (rc != X86EMUL_CONTINUE) return rc; - rc = assign_eip_far(ctxt, ctxt->src.val, &new_desc); + rc = assign_eip_far(ctxt, ctxt->src.val); /* Error handling is not implemented. */ if (rc != X86EMUL_CONTINUE) return X86EMUL_UNHANDLEABLE; @@ -2250,7 +2248,7 @@ static int em_ret_far(struct x86_emulate_ctxt *ctxt) &new_desc); if (rc != X86EMUL_CONTINUE) return rc; - rc = assign_eip_far(ctxt, eip, &new_desc); + rc = assign_eip_far(ctxt, eip); /* Error handling is not implemented. */ if (rc != X86EMUL_CONTINUE) return X86EMUL_UNHANDLEABLE; @@ -2309,335 +2307,15 @@ static int em_lseg(struct x86_emulate_ctxt *ctxt) return rc; } -static int emulator_has_longmode(struct x86_emulate_ctxt *ctxt) -{ -#ifdef CONFIG_X86_64 - return ctxt->ops->guest_has_long_mode(ctxt); -#else - return false; -#endif -} - -static void rsm_set_desc_flags(struct desc_struct *desc, u32 flags) -{ - desc->g = (flags >> 23) & 1; - desc->d = (flags >> 22) & 1; - desc->l = (flags >> 21) & 1; - desc->avl = (flags >> 20) & 1; - desc->p = (flags >> 15) & 1; - desc->dpl = (flags >> 13) & 3; - desc->s = (flags >> 12) & 1; - desc->type = (flags >> 8) & 15; -} - -static int rsm_load_seg_32(struct x86_emulate_ctxt *ctxt, const char *smstate, - int n) -{ - struct desc_struct desc; - int offset; - u16 selector; - - selector = GET_SMSTATE(u32, smstate, 0x7fa8 + n * 4); - - if (n < 3) - offset = 0x7f84 + n * 12; - else - offset = 0x7f2c + (n - 3) * 12; - - set_desc_base(&desc, GET_SMSTATE(u32, smstate, offset + 8)); - set_desc_limit(&desc, GET_SMSTATE(u32, smstate, offset + 4)); - rsm_set_desc_flags(&desc, GET_SMSTATE(u32, smstate, offset)); - ctxt->ops->set_segment(ctxt, selector, &desc, 0, n); - return X86EMUL_CONTINUE; -} - -#ifdef CONFIG_X86_64 -static int rsm_load_seg_64(struct x86_emulate_ctxt *ctxt, const char *smstate, - int n) -{ - struct desc_struct desc; - int offset; - u16 selector; - u32 base3; - - offset = 0x7e00 + n * 16; - - selector = GET_SMSTATE(u16, smstate, offset); - rsm_set_desc_flags(&desc, GET_SMSTATE(u16, smstate, offset + 2) << 8); - set_desc_limit(&desc, GET_SMSTATE(u32, smstate, offset + 4)); - set_desc_base(&desc, GET_SMSTATE(u32, smstate, offset + 8)); - base3 = GET_SMSTATE(u32, smstate, offset + 12); - - ctxt->ops->set_segment(ctxt, selector, &desc, base3, n); - return X86EMUL_CONTINUE; -} -#endif - -static int rsm_enter_protected_mode(struct x86_emulate_ctxt *ctxt, - u64 cr0, u64 cr3, u64 cr4) -{ - int bad; - u64 pcid; - - /* In order to later set CR4.PCIDE, CR3[11:0] must be zero. */ - pcid = 0; - if (cr4 & X86_CR4_PCIDE) { - pcid = cr3 & 0xfff; - cr3 &= ~0xfff; - } - - bad = ctxt->ops->set_cr(ctxt, 3, cr3); - if (bad) - return X86EMUL_UNHANDLEABLE; - - /* - * First enable PAE, long mode needs it before CR0.PG = 1 is set. - * Then enable protected mode. However, PCID cannot be enabled - * if EFER.LMA=0, so set it separately. - */ - bad = ctxt->ops->set_cr(ctxt, 4, cr4 & ~X86_CR4_PCIDE); - if (bad) - return X86EMUL_UNHANDLEABLE; - - bad = ctxt->ops->set_cr(ctxt, 0, cr0); - if (bad) - return X86EMUL_UNHANDLEABLE; - - if (cr4 & X86_CR4_PCIDE) { - bad = ctxt->ops->set_cr(ctxt, 4, cr4); - if (bad) - return X86EMUL_UNHANDLEABLE; - if (pcid) { - bad = ctxt->ops->set_cr(ctxt, 3, cr3 | pcid); - if (bad) - return X86EMUL_UNHANDLEABLE; - } - - } - - return X86EMUL_CONTINUE; -} - -static int rsm_load_state_32(struct x86_emulate_ctxt *ctxt, - const char *smstate) -{ - struct desc_struct desc; - struct desc_ptr dt; - u16 selector; - u32 val, cr0, cr3, cr4; - int i; - - cr0 = GET_SMSTATE(u32, smstate, 0x7ffc); - cr3 = GET_SMSTATE(u32, smstate, 0x7ff8); - ctxt->eflags = GET_SMSTATE(u32, smstate, 0x7ff4) | X86_EFLAGS_FIXED; - ctxt->_eip = GET_SMSTATE(u32, smstate, 0x7ff0); - - for (i = 0; i < NR_EMULATOR_GPRS; i++) - *reg_write(ctxt, i) = GET_SMSTATE(u32, smstate, 0x7fd0 + i * 4); - - val = GET_SMSTATE(u32, smstate, 0x7fcc); - - if (ctxt->ops->set_dr(ctxt, 6, val)) - return X86EMUL_UNHANDLEABLE; - - val = GET_SMSTATE(u32, smstate, 0x7fc8); - - if (ctxt->ops->set_dr(ctxt, 7, val)) - return X86EMUL_UNHANDLEABLE; - - selector = GET_SMSTATE(u32, smstate, 0x7fc4); - set_desc_base(&desc, GET_SMSTATE(u32, smstate, 0x7f64)); - set_desc_limit(&desc, GET_SMSTATE(u32, smstate, 0x7f60)); - rsm_set_desc_flags(&desc, GET_SMSTATE(u32, smstate, 0x7f5c)); - ctxt->ops->set_segment(ctxt, selector, &desc, 0, VCPU_SREG_TR); - - selector = GET_SMSTATE(u32, smstate, 0x7fc0); - set_desc_base(&desc, GET_SMSTATE(u32, smstate, 0x7f80)); - set_desc_limit(&desc, GET_SMSTATE(u32, smstate, 0x7f7c)); - rsm_set_desc_flags(&desc, GET_SMSTATE(u32, smstate, 0x7f78)); - ctxt->ops->set_segment(ctxt, selector, &desc, 0, VCPU_SREG_LDTR); - - dt.address = GET_SMSTATE(u32, smstate, 0x7f74); - dt.size = GET_SMSTATE(u32, smstate, 0x7f70); - ctxt->ops->set_gdt(ctxt, &dt); - - dt.address = GET_SMSTATE(u32, smstate, 0x7f58); - dt.size = GET_SMSTATE(u32, smstate, 0x7f54); - ctxt->ops->set_idt(ctxt, &dt); - - for (i = 0; i < 6; i++) { - int r = rsm_load_seg_32(ctxt, smstate, i); - if (r != X86EMUL_CONTINUE) - return r; - } - - cr4 = GET_SMSTATE(u32, smstate, 0x7f14); - - ctxt->ops->set_smbase(ctxt, GET_SMSTATE(u32, smstate, 0x7ef8)); - - return rsm_enter_protected_mode(ctxt, cr0, cr3, cr4); -} - -#ifdef CONFIG_X86_64 -static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, - const char *smstate) -{ - struct desc_struct desc; - struct desc_ptr dt; - u64 val, cr0, cr3, cr4; - u32 base3; - u16 selector; - int i, r; - - for (i = 0; i < NR_EMULATOR_GPRS; i++) - *reg_write(ctxt, i) = GET_SMSTATE(u64, smstate, 0x7ff8 - i * 8); - - ctxt->_eip = GET_SMSTATE(u64, smstate, 0x7f78); - ctxt->eflags = GET_SMSTATE(u32, smstate, 0x7f70) | X86_EFLAGS_FIXED; - - val = GET_SMSTATE(u64, smstate, 0x7f68); - - if (ctxt->ops->set_dr(ctxt, 6, val)) - return X86EMUL_UNHANDLEABLE; - - val = GET_SMSTATE(u64, smstate, 0x7f60); - - if (ctxt->ops->set_dr(ctxt, 7, val)) - return X86EMUL_UNHANDLEABLE; - - cr0 = GET_SMSTATE(u64, smstate, 0x7f58); - cr3 = GET_SMSTATE(u64, smstate, 0x7f50); - cr4 = GET_SMSTATE(u64, smstate, 0x7f48); - ctxt->ops->set_smbase(ctxt, GET_SMSTATE(u32, smstate, 0x7f00)); - val = GET_SMSTATE(u64, smstate, 0x7ed0); - - if (ctxt->ops->set_msr(ctxt, MSR_EFER, val & ~EFER_LMA)) - return X86EMUL_UNHANDLEABLE; - - selector = GET_SMSTATE(u32, smstate, 0x7e90); - rsm_set_desc_flags(&desc, GET_SMSTATE(u32, smstate, 0x7e92) << 8); - set_desc_limit(&desc, GET_SMSTATE(u32, smstate, 0x7e94)); - set_desc_base(&desc, GET_SMSTATE(u32, smstate, 0x7e98)); - base3 = GET_SMSTATE(u32, smstate, 0x7e9c); - ctxt->ops->set_segment(ctxt, selector, &desc, base3, VCPU_SREG_TR); - - dt.size = GET_SMSTATE(u32, smstate, 0x7e84); - dt.address = GET_SMSTATE(u64, smstate, 0x7e88); - ctxt->ops->set_idt(ctxt, &dt); - - selector = GET_SMSTATE(u32, smstate, 0x7e70); - rsm_set_desc_flags(&desc, GET_SMSTATE(u32, smstate, 0x7e72) << 8); - set_desc_limit(&desc, GET_SMSTATE(u32, smstate, 0x7e74)); - set_desc_base(&desc, GET_SMSTATE(u32, smstate, 0x7e78)); - base3 = GET_SMSTATE(u32, smstate, 0x7e7c); - ctxt->ops->set_segment(ctxt, selector, &desc, base3, VCPU_SREG_LDTR); - - dt.size = GET_SMSTATE(u32, smstate, 0x7e64); - dt.address = GET_SMSTATE(u64, smstate, 0x7e68); - ctxt->ops->set_gdt(ctxt, &dt); - - r = rsm_enter_protected_mode(ctxt, cr0, cr3, cr4); - if (r != X86EMUL_CONTINUE) - return r; - - for (i = 0; i < 6; i++) { - r = rsm_load_seg_64(ctxt, smstate, i); - if (r != X86EMUL_CONTINUE) - return r; - } - - return X86EMUL_CONTINUE; -} -#endif - static int em_rsm(struct x86_emulate_ctxt *ctxt) { - unsigned long cr0, cr4, efer; - char buf[512]; - u64 smbase; - int ret; - if ((ctxt->ops->get_hflags(ctxt) & X86EMUL_SMM_MASK) == 0) return emulate_ud(ctxt); - smbase = ctxt->ops->get_smbase(ctxt); - - ret = ctxt->ops->read_phys(ctxt, smbase + 0xfe00, buf, sizeof(buf)); - if (ret != X86EMUL_CONTINUE) - return X86EMUL_UNHANDLEABLE; - - if ((ctxt->ops->get_hflags(ctxt) & X86EMUL_SMM_INSIDE_NMI_MASK) == 0) - ctxt->ops->set_nmi_mask(ctxt, false); - - ctxt->ops->exiting_smm(ctxt); - - /* - * Get back to real mode, to prepare a safe state in which to load - * CR0/CR3/CR4/EFER. It's all a bit more complicated if the vCPU - * supports long mode. - */ - if (emulator_has_longmode(ctxt)) { - struct desc_struct cs_desc; - - /* Zero CR4.PCIDE before CR0.PG. */ - cr4 = ctxt->ops->get_cr(ctxt, 4); - if (cr4 & X86_CR4_PCIDE) - ctxt->ops->set_cr(ctxt, 4, cr4 & ~X86_CR4_PCIDE); - - /* A 32-bit code segment is required to clear EFER.LMA. */ - memset(&cs_desc, 0, sizeof(cs_desc)); - cs_desc.type = 0xb; - cs_desc.s = cs_desc.g = cs_desc.p = 1; - ctxt->ops->set_segment(ctxt, 0, &cs_desc, 0, VCPU_SREG_CS); - } - - /* For the 64-bit case, this will clear EFER.LMA. */ - cr0 = ctxt->ops->get_cr(ctxt, 0); - if (cr0 & X86_CR0_PE) - ctxt->ops->set_cr(ctxt, 0, cr0 & ~(X86_CR0_PG | X86_CR0_PE)); - - if (emulator_has_longmode(ctxt)) { - /* Clear CR4.PAE before clearing EFER.LME. */ - cr4 = ctxt->ops->get_cr(ctxt, 4); - if (cr4 & X86_CR4_PAE) - ctxt->ops->set_cr(ctxt, 4, cr4 & ~X86_CR4_PAE); - - /* And finally go back to 32-bit mode. */ - efer = 0; - ctxt->ops->set_msr(ctxt, MSR_EFER, efer); - } - - /* - * Give leave_smm() a chance to make ISA-specific changes to the vCPU - * state (e.g. enter guest mode) before loading state from the SMM - * state-save area. - */ - if (ctxt->ops->leave_smm(ctxt, buf)) - goto emulate_shutdown; - -#ifdef CONFIG_X86_64 - if (emulator_has_longmode(ctxt)) - ret = rsm_load_state_64(ctxt, buf); - else -#endif - ret = rsm_load_state_32(ctxt, buf); - - if (ret != X86EMUL_CONTINUE) - goto emulate_shutdown; - - /* - * Note, the ctxt->ops callbacks are responsible for handling side - * effects when writing MSRs and CRs, e.g. MMU context resets, CPUID - * runtime updates, etc... If that changes, e.g. this flow is moved - * out of the emulator to make it look more like enter_smm(), then - * those side effects need to be explicitly handled for both success - * and shutdown. - */ - return X86EMUL_CONTINUE; + if (ctxt->ops->leave_smm(ctxt)) + ctxt->ops->triple_fault(ctxt); -emulate_shutdown: - ctxt->ops->triple_fault(ctxt); - return X86EMUL_CONTINUE; + return emulator_recalc_and_set_mode(ctxt); } static void @@ -2876,6 +2554,7 @@ static int em_sysexit(struct x86_emulate_ctxt *ctxt) ops->set_segment(ctxt, ss_sel, &ss, 0, VCPU_SREG_SS); ctxt->_eip = rdx; + ctxt->mode = usermode; *reg_write(ctxt, VCPU_REGS_RSP) = rcx; return X86EMUL_CONTINUE; @@ -3469,7 +3148,7 @@ static int em_call_far(struct x86_emulate_ctxt *ctxt) if (rc != X86EMUL_CONTINUE) return rc; - rc = assign_eip_far(ctxt, ctxt->src.val, &new_desc); + rc = assign_eip_far(ctxt, ctxt->src.val); if (rc != X86EMUL_CONTINUE) goto fail; @@ -3611,11 +3290,25 @@ static int em_movbe(struct x86_emulate_ctxt *ctxt) static int em_cr_write(struct x86_emulate_ctxt *ctxt) { - if (ctxt->ops->set_cr(ctxt, ctxt->modrm_reg, ctxt->src.val)) + int cr_num = ctxt->modrm_reg; + int r; + + if (ctxt->ops->set_cr(ctxt, cr_num, ctxt->src.val)) return emulate_gp(ctxt, 0); /* Disable writeback. */ ctxt->dst.type = OP_NONE; + + if (cr_num == 0) { + /* + * CR0 write might have updated CR0.PE and/or CR0.PG + * which can affect the cpu's execution mode. + */ + r = emulator_recalc_and_set_mode(ctxt); + if (r != X86EMUL_CONTINUE) + return r; + } + return X86EMUL_CONTINUE; } |