diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index e8a58409b5ac0e2788a96a2fb97be7b77dea82bd..47e716ef46b7a0f3d5aa3f56593fb63263968966 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -1410,11 +1410,11 @@ static int write_segment_descriptor(struct x86_emulate_ctxt *ctxt, } /* Does not support long mode */ -static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt, - u16 selector, int seg) +static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt, + u16 selector, int seg, u8 cpl) { struct desc_struct seg_desc, old_desc; - u8 dpl, rpl, cpl; + u8 dpl, rpl; unsigned err_vec = GP_VECTOR; u32 err_code = 0; bool null_selector = !(selector & ~0x3); /* 0000-0003 are null */ @@ -1442,7 +1442,6 @@ static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt, } rpl = selector & 3; - cpl = ctxt->ops->cpl(ctxt); /* NULL selector is not valid for TR, CS and SS (except for long mode) */ if ((seg == VCPU_SREG_CS @@ -1544,6 +1543,13 @@ static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt, return X86EMUL_PROPAGATE_FAULT; } +static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt, + u16 selector, int seg) +{ + u8 cpl = ctxt->ops->cpl(ctxt); + return __load_segment_descriptor(ctxt, selector, seg, cpl); +} + static void write_register_operand(struct operand *op) { /* The 4-byte case *is* correct: in 64-bit mode we zero-extend. */ @@ -2405,6 +2411,7 @@ static int load_state_from_tss16(struct x86_emulate_ctxt *ctxt, struct tss_segment_16 *tss) { int ret; + u8 cpl; ctxt->_eip = tss->ip; ctxt->eflags = tss->flag | 2; @@ -2427,23 +2434,25 @@ static int load_state_from_tss16(struct x86_emulate_ctxt *ctxt, set_segment_selector(ctxt, tss->ss, VCPU_SREG_SS); set_segment_selector(ctxt, tss->ds, VCPU_SREG_DS); + cpl = tss->cs & 3; + /* * Now load segment descriptors. If fault happens at this stage * it is handled in a context of new task */ - ret = load_segment_descriptor(ctxt, tss->ldt, VCPU_SREG_LDTR); + ret = __load_segment_descriptor(ctxt, tss->ldt, VCPU_SREG_LDTR, cpl); if (ret != X86EMUL_CONTINUE) return ret; - ret = load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES); + ret = __load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES, cpl); if (ret != X86EMUL_CONTINUE) return ret; - ret = load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS); + ret = __load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS, cpl); if (ret != X86EMUL_CONTINUE) return ret; - ret = load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS); + ret = __load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS, cpl); if (ret != X86EMUL_CONTINUE) return ret; - ret = load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS); + ret = __load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS, cpl); if (ret != X86EMUL_CONTINUE) return ret; @@ -2521,6 +2530,7 @@ static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt, struct tss_segment_32 *tss) { int ret; + u8 cpl; if (ctxt->ops->set_cr(ctxt, 3, tss->cr3)) return emulate_gp(ctxt, 0); @@ -2539,7 +2549,8 @@ static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt, /* * SDM says that segment selectors are loaded before segment - * descriptors + * descriptors. This is important because CPL checks will + * use CS.RPL. */ set_segment_selector(ctxt, tss->ldt_selector, VCPU_SREG_LDTR); set_segment_selector(ctxt, tss->es, VCPU_SREG_ES); @@ -2553,43 +2564,38 @@ static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt, * If we're switching between Protected Mode and VM86, we need to make * sure to update the mode before loading the segment descriptors so * that the selectors are interpreted correctly. - * - * Need to get rflags to the vcpu struct immediately because it - * influences the CPL which is checked at least when loading the segment - * descriptors and when pushing an error code to the new kernel stack. - * - * TODO Introduce a separate ctxt->ops->set_cpl callback */ - if (ctxt->eflags & X86_EFLAGS_VM) + if (ctxt->eflags & X86_EFLAGS_VM) { ctxt->mode = X86EMUL_MODE_VM86; - else + cpl = 3; + } else { ctxt->mode = X86EMUL_MODE_PROT32; - - ctxt->ops->set_rflags(ctxt, ctxt->eflags); + cpl = tss->cs & 3; + } /* * Now load segment descriptors. If fault happenes at this stage * it is handled in a context of new task */ - ret = load_segment_descriptor(ctxt, tss->ldt_selector, VCPU_SREG_LDTR); + ret = __load_segment_descriptor(ctxt, tss->ldt_selector, VCPU_SREG_LDTR, cpl); if (ret != X86EMUL_CONTINUE) return ret; - ret = load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES); + ret = __load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES, cpl); if (ret != X86EMUL_CONTINUE) return ret; - ret = load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS); + ret = __load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS, cpl); if (ret != X86EMUL_CONTINUE) return ret; - ret = load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS); + ret = __load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS, cpl); if (ret != X86EMUL_CONTINUE) return ret; - ret = load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS); + ret = __load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS, cpl); if (ret != X86EMUL_CONTINUE) return ret; - ret = load_segment_descriptor(ctxt, tss->fs, VCPU_SREG_FS); + ret = __load_segment_descriptor(ctxt, tss->fs, VCPU_SREG_FS, cpl); if (ret != X86EMUL_CONTINUE) return ret; - ret = load_segment_descriptor(ctxt, tss->gs, VCPU_SREG_GS); + ret = __load_segment_descriptor(ctxt, tss->gs, VCPU_SREG_GS, cpl); if (ret != X86EMUL_CONTINUE) return ret;