From ceffb4597253b2420d2f171d8b1cdf2cd3137989 Mon Sep 17 00:00:00 2001 From: Gleb Natapov Date: Thu, 18 Mar 2010 15:20:19 +0200 Subject: [PATCH] KVM: Use task switch from emulator.c Remove old task switch code from x86.c Signed-off-by: Gleb Natapov Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/emulate.c | 6 +- arch/x86/kvm/x86.c | 561 ++--------------------------------------- 2 files changed, 22 insertions(+), 545 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 702bffffd27f..8225ec26efed 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2291,6 +2291,7 @@ static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt, u16 old_tss_sel = ops->get_segment_selector(VCPU_SREG_TR, ctxt->vcpu); ulong old_tss_base = get_cached_descriptor_base(ctxt, ops, VCPU_SREG_TR); + u32 desc_limit; /* FIXME: old_tss_base == ~0 ? */ @@ -2311,7 +2312,10 @@ static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt, } } - if (!next_tss_desc.p || desc_limit_scaled(&next_tss_desc) < 0x67) { + desc_limit = desc_limit_scaled(&next_tss_desc); + if (!next_tss_desc.p || + ((desc_limit < 0x67 && (next_tss_desc.type & 8)) || + desc_limit < 0x2b)) { kvm_queue_exception_e(ctxt->vcpu, TS_VECTOR, tss_selector & 0xfffc); return X86EMUL_PROPAGATE_FAULT; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index fbee8fbb33b5..f69854c8f339 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4832,557 +4832,30 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu, return 0; } -static void seg_desct_to_kvm_desct(struct desc_struct *seg_desc, u16 selector, - struct kvm_segment *kvm_desct) -{ - kvm_desct->base = get_desc_base(seg_desc); - kvm_desct->limit = get_desc_limit(seg_desc); - if (seg_desc->g) { - kvm_desct->limit <<= 12; - kvm_desct->limit |= 0xfff; - } - kvm_desct->selector = selector; - kvm_desct->type = seg_desc->type; - kvm_desct->present = seg_desc->p; - kvm_desct->dpl = seg_desc->dpl; - kvm_desct->db = seg_desc->d; - kvm_desct->s = seg_desc->s; - kvm_desct->l = seg_desc->l; - kvm_desct->g = seg_desc->g; - kvm_desct->avl = seg_desc->avl; - if (!selector) - kvm_desct->unusable = 1; - else - kvm_desct->unusable = 0; - kvm_desct->padding = 0; -} - -static void get_segment_descriptor_dtable(struct kvm_vcpu *vcpu, - u16 selector, - struct desc_ptr *dtable) -{ - if (selector & 1 << 2) { - struct kvm_segment kvm_seg; - - kvm_get_segment(vcpu, &kvm_seg, VCPU_SREG_LDTR); - - if (kvm_seg.unusable) - dtable->size = 0; - else - dtable->size = kvm_seg.limit; - dtable->address = kvm_seg.base; - } - else - kvm_x86_ops->get_gdt(vcpu, dtable); -} - -/* allowed just for 8 bytes segments */ -static int load_guest_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, - struct desc_struct *seg_desc) -{ - struct desc_ptr dtable; - u16 index = selector >> 3; - int ret; - u32 err; - gva_t addr; - - get_segment_descriptor_dtable(vcpu, selector, &dtable); - - if (dtable.size < index * 8 + 7) { - kvm_queue_exception_e(vcpu, GP_VECTOR, selector & 0xfffc); - return X86EMUL_PROPAGATE_FAULT; - } - addr = dtable.base + index * 8; - ret = kvm_read_guest_virt_system(addr, seg_desc, sizeof(*seg_desc), - vcpu, &err); - if (ret == X86EMUL_PROPAGATE_FAULT) - kvm_inject_page_fault(vcpu, addr, err); - - return ret; -} - -/* allowed just for 8 bytes segments */ -static int save_guest_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, - struct desc_struct *seg_desc) -{ - struct desc_ptr dtable; - u16 index = selector >> 3; - - get_segment_descriptor_dtable(vcpu, selector, &dtable); - - if (dtable.size < index * 8 + 7) - return 1; - return kvm_write_guest_virt(dtable.address + index*8, seg_desc, sizeof(*seg_desc), vcpu, NULL); -} - -static gpa_t get_tss_base_addr_write(struct kvm_vcpu *vcpu, - struct desc_struct *seg_desc) -{ - u32 base_addr = get_desc_base(seg_desc); - - return kvm_mmu_gva_to_gpa_write(vcpu, base_addr, NULL); -} - -static gpa_t get_tss_base_addr_read(struct kvm_vcpu *vcpu, - struct desc_struct *seg_desc) -{ - u32 base_addr = get_desc_base(seg_desc); - - return kvm_mmu_gva_to_gpa_read(vcpu, base_addr, NULL); -} - -static u16 get_segment_selector(struct kvm_vcpu *vcpu, int seg) -{ - struct kvm_segment kvm_seg; - - kvm_get_segment(vcpu, &kvm_seg, seg); - return kvm_seg.selector; -} - -static int kvm_load_realmode_segment(struct kvm_vcpu *vcpu, u16 selector, int seg) -{ - struct kvm_segment segvar = { - .base = selector << 4, - .limit = 0xffff, - .selector = selector, - .type = 3, - .present = 1, - .dpl = 3, - .db = 0, - .s = 1, - .l = 0, - .g = 0, - .avl = 0, - .unusable = 0, - }; - kvm_x86_ops->set_segment(vcpu, &segvar, seg); - return X86EMUL_CONTINUE; -} - -static int is_vm86_segment(struct kvm_vcpu *vcpu, int seg) -{ - return (seg != VCPU_SREG_LDTR) && - (seg != VCPU_SREG_TR) && - (kvm_get_rflags(vcpu) & X86_EFLAGS_VM); -} - -int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, int seg) -{ - struct kvm_segment kvm_seg; - struct desc_struct seg_desc; - u8 dpl, rpl, cpl; - unsigned err_vec = GP_VECTOR; - u32 err_code = 0; - bool null_selector = !(selector & ~0x3); /* 0000-0003 are null */ - int ret; - - if (is_vm86_segment(vcpu, seg) || !is_protmode(vcpu)) - return kvm_load_realmode_segment(vcpu, selector, seg); - - /* NULL selector is not valid for TR, CS and SS */ - if ((seg == VCPU_SREG_CS || seg == VCPU_SREG_SS || seg == VCPU_SREG_TR) - && null_selector) - goto exception; - - /* TR should be in GDT only */ - if (seg == VCPU_SREG_TR && (selector & (1 << 2))) - goto exception; - - ret = load_guest_segment_descriptor(vcpu, selector, &seg_desc); - if (ret) - return ret; - - seg_desct_to_kvm_desct(&seg_desc, selector, &kvm_seg); - - if (null_selector) { /* for NULL selector skip all following checks */ - kvm_seg.unusable = 1; - goto load; - } - - err_code = selector & 0xfffc; - err_vec = GP_VECTOR; - - /* can't load system descriptor into segment selecor */ - if (seg <= VCPU_SREG_GS && !kvm_seg.s) - goto exception; - - if (!kvm_seg.present) { - err_vec = (seg == VCPU_SREG_SS) ? SS_VECTOR : NP_VECTOR; - goto exception; - } - - rpl = selector & 3; - dpl = kvm_seg.dpl; - cpl = kvm_x86_ops->get_cpl(vcpu); - - switch (seg) { - case VCPU_SREG_SS: - /* - * segment is not a writable data segment or segment - * selector's RPL != CPL or segment selector's RPL != CPL - */ - if (rpl != cpl || (kvm_seg.type & 0xa) != 0x2 || dpl != cpl) - goto exception; - break; - case VCPU_SREG_CS: - if (!(kvm_seg.type & 8)) - goto exception; - - if (kvm_seg.type & 4) { - /* conforming */ - if (dpl > cpl) - goto exception; - } else { - /* nonconforming */ - if (rpl > cpl || dpl != cpl) - goto exception; - } - /* CS(RPL) <- CPL */ - selector = (selector & 0xfffc) | cpl; - break; - case VCPU_SREG_TR: - if (kvm_seg.s || (kvm_seg.type != 1 && kvm_seg.type != 9)) - goto exception; - break; - case VCPU_SREG_LDTR: - if (kvm_seg.s || kvm_seg.type != 2) - goto exception; - break; - default: /* DS, ES, FS, or GS */ - /* - * segment is not a data or readable code segment or - * ((segment is a data or nonconforming code segment) - * and (both RPL and CPL > DPL)) - */ - if ((kvm_seg.type & 0xa) == 0x8 || - (((kvm_seg.type & 0xc) != 0xc) && (rpl > dpl && cpl > dpl))) - goto exception; - break; - } - - if (!kvm_seg.unusable && kvm_seg.s) { - /* mark segment as accessed */ - kvm_seg.type |= 1; - seg_desc.type |= 1; - save_guest_segment_descriptor(vcpu, selector, &seg_desc); - } -load: - kvm_set_segment(vcpu, &kvm_seg, seg); - return X86EMUL_CONTINUE; -exception: - kvm_queue_exception_e(vcpu, err_vec, err_code); - return X86EMUL_PROPAGATE_FAULT; -} - -static void save_state_to_tss32(struct kvm_vcpu *vcpu, - struct tss_segment_32 *tss) -{ - tss->cr3 = vcpu->arch.cr3; - tss->eip = kvm_rip_read(vcpu); - tss->eflags = kvm_get_rflags(vcpu); - tss->eax = kvm_register_read(vcpu, VCPU_REGS_RAX); - tss->ecx = kvm_register_read(vcpu, VCPU_REGS_RCX); - tss->edx = kvm_register_read(vcpu, VCPU_REGS_RDX); - tss->ebx = kvm_register_read(vcpu, VCPU_REGS_RBX); - tss->esp = kvm_register_read(vcpu, VCPU_REGS_RSP); - tss->ebp = kvm_register_read(vcpu, VCPU_REGS_RBP); - tss->esi = kvm_register_read(vcpu, VCPU_REGS_RSI); - tss->edi = kvm_register_read(vcpu, VCPU_REGS_RDI); - tss->es = get_segment_selector(vcpu, VCPU_SREG_ES); - tss->cs = get_segment_selector(vcpu, VCPU_SREG_CS); - tss->ss = get_segment_selector(vcpu, VCPU_SREG_SS); - tss->ds = get_segment_selector(vcpu, VCPU_SREG_DS); - tss->fs = get_segment_selector(vcpu, VCPU_SREG_FS); - tss->gs = get_segment_selector(vcpu, VCPU_SREG_GS); - tss->ldt_selector = get_segment_selector(vcpu, VCPU_SREG_LDTR); -} - -static void kvm_load_segment_selector(struct kvm_vcpu *vcpu, u16 sel, int seg) -{ - struct kvm_segment kvm_seg; - kvm_get_segment(vcpu, &kvm_seg, seg); - kvm_seg.selector = sel; - kvm_set_segment(vcpu, &kvm_seg, seg); -} - -static int load_state_from_tss32(struct kvm_vcpu *vcpu, - struct tss_segment_32 *tss) -{ - kvm_set_cr3(vcpu, tss->cr3); - - kvm_rip_write(vcpu, tss->eip); - kvm_set_rflags(vcpu, tss->eflags | 2); - - kvm_register_write(vcpu, VCPU_REGS_RAX, tss->eax); - kvm_register_write(vcpu, VCPU_REGS_RCX, tss->ecx); - kvm_register_write(vcpu, VCPU_REGS_RDX, tss->edx); - kvm_register_write(vcpu, VCPU_REGS_RBX, tss->ebx); - kvm_register_write(vcpu, VCPU_REGS_RSP, tss->esp); - kvm_register_write(vcpu, VCPU_REGS_RBP, tss->ebp); - kvm_register_write(vcpu, VCPU_REGS_RSI, tss->esi); - kvm_register_write(vcpu, VCPU_REGS_RDI, tss->edi); - - /* - * SDM says that segment selectors are loaded before segment - * descriptors - */ - kvm_load_segment_selector(vcpu, tss->ldt_selector, VCPU_SREG_LDTR); - kvm_load_segment_selector(vcpu, tss->es, VCPU_SREG_ES); - kvm_load_segment_selector(vcpu, tss->cs, VCPU_SREG_CS); - kvm_load_segment_selector(vcpu, tss->ss, VCPU_SREG_SS); - kvm_load_segment_selector(vcpu, tss->ds, VCPU_SREG_DS); - kvm_load_segment_selector(vcpu, tss->fs, VCPU_SREG_FS); - kvm_load_segment_selector(vcpu, tss->gs, VCPU_SREG_GS); - - /* - * Now load segment descriptors. If fault happenes at this stage - * it is handled in a context of new task - */ - if (kvm_load_segment_descriptor(vcpu, tss->ldt_selector, VCPU_SREG_LDTR)) - return 1; - - if (kvm_load_segment_descriptor(vcpu, tss->es, VCPU_SREG_ES)) - return 1; - - if (kvm_load_segment_descriptor(vcpu, tss->cs, VCPU_SREG_CS)) - return 1; - - if (kvm_load_segment_descriptor(vcpu, tss->ss, VCPU_SREG_SS)) - return 1; - - if (kvm_load_segment_descriptor(vcpu, tss->ds, VCPU_SREG_DS)) - return 1; - - if (kvm_load_segment_descriptor(vcpu, tss->fs, VCPU_SREG_FS)) - return 1; - - if (kvm_load_segment_descriptor(vcpu, tss->gs, VCPU_SREG_GS)) - return 1; - return 0; -} - -static void save_state_to_tss16(struct kvm_vcpu *vcpu, - struct tss_segment_16 *tss) -{ - tss->ip = kvm_rip_read(vcpu); - tss->flag = kvm_get_rflags(vcpu); - tss->ax = kvm_register_read(vcpu, VCPU_REGS_RAX); - tss->cx = kvm_register_read(vcpu, VCPU_REGS_RCX); - tss->dx = kvm_register_read(vcpu, VCPU_REGS_RDX); - tss->bx = kvm_register_read(vcpu, VCPU_REGS_RBX); - tss->sp = kvm_register_read(vcpu, VCPU_REGS_RSP); - tss->bp = kvm_register_read(vcpu, VCPU_REGS_RBP); - tss->si = kvm_register_read(vcpu, VCPU_REGS_RSI); - tss->di = kvm_register_read(vcpu, VCPU_REGS_RDI); - - tss->es = get_segment_selector(vcpu, VCPU_SREG_ES); - tss->cs = get_segment_selector(vcpu, VCPU_SREG_CS); - tss->ss = get_segment_selector(vcpu, VCPU_SREG_SS); - tss->ds = get_segment_selector(vcpu, VCPU_SREG_DS); - tss->ldt = get_segment_selector(vcpu, VCPU_SREG_LDTR); -} - -static int load_state_from_tss16(struct kvm_vcpu *vcpu, - struct tss_segment_16 *tss) -{ - kvm_rip_write(vcpu, tss->ip); - kvm_set_rflags(vcpu, tss->flag | 2); - kvm_register_write(vcpu, VCPU_REGS_RAX, tss->ax); - kvm_register_write(vcpu, VCPU_REGS_RCX, tss->cx); - kvm_register_write(vcpu, VCPU_REGS_RDX, tss->dx); - kvm_register_write(vcpu, VCPU_REGS_RBX, tss->bx); - kvm_register_write(vcpu, VCPU_REGS_RSP, tss->sp); - kvm_register_write(vcpu, VCPU_REGS_RBP, tss->bp); - kvm_register_write(vcpu, VCPU_REGS_RSI, tss->si); - kvm_register_write(vcpu, VCPU_REGS_RDI, tss->di); - - /* - * SDM says that segment selectors are loaded before segment - * descriptors - */ - kvm_load_segment_selector(vcpu, tss->ldt, VCPU_SREG_LDTR); - kvm_load_segment_selector(vcpu, tss->es, VCPU_SREG_ES); - kvm_load_segment_selector(vcpu, tss->cs, VCPU_SREG_CS); - kvm_load_segment_selector(vcpu, tss->ss, VCPU_SREG_SS); - kvm_load_segment_selector(vcpu, tss->ds, VCPU_SREG_DS); - - /* - * Now load segment descriptors. If fault happenes at this stage - * it is handled in a context of new task - */ - if (kvm_load_segment_descriptor(vcpu, tss->ldt, VCPU_SREG_LDTR)) - return 1; - - if (kvm_load_segment_descriptor(vcpu, tss->es, VCPU_SREG_ES)) - return 1; - - if (kvm_load_segment_descriptor(vcpu, tss->cs, VCPU_SREG_CS)) - return 1; - - if (kvm_load_segment_descriptor(vcpu, tss->ss, VCPU_SREG_SS)) - return 1; - - if (kvm_load_segment_descriptor(vcpu, tss->ds, VCPU_SREG_DS)) - return 1; - return 0; -} - -static int kvm_task_switch_16(struct kvm_vcpu *vcpu, u16 tss_selector, - u16 old_tss_sel, u32 old_tss_base, - struct desc_struct *nseg_desc) -{ - struct tss_segment_16 tss_segment_16; - int ret = 0; - - if (kvm_read_guest(vcpu->kvm, old_tss_base, &tss_segment_16, - sizeof tss_segment_16)) - goto out; - - save_state_to_tss16(vcpu, &tss_segment_16); - - if (kvm_write_guest(vcpu->kvm, old_tss_base, &tss_segment_16, - sizeof tss_segment_16)) - goto out; - - if (kvm_read_guest(vcpu->kvm, get_tss_base_addr_read(vcpu, nseg_desc), - &tss_segment_16, sizeof tss_segment_16)) - goto out; - - if (old_tss_sel != 0xffff) { - tss_segment_16.prev_task_link = old_tss_sel; - - if (kvm_write_guest(vcpu->kvm, - get_tss_base_addr_write(vcpu, nseg_desc), - &tss_segment_16.prev_task_link, - sizeof tss_segment_16.prev_task_link)) - goto out; - } - - if (load_state_from_tss16(vcpu, &tss_segment_16)) - goto out; - - ret = 1; -out: - return ret; -} - -static int kvm_task_switch_32(struct kvm_vcpu *vcpu, u16 tss_selector, - u16 old_tss_sel, u32 old_tss_base, - struct desc_struct *nseg_desc) -{ - struct tss_segment_32 tss_segment_32; - int ret = 0; - - if (kvm_read_guest(vcpu->kvm, old_tss_base, &tss_segment_32, - sizeof tss_segment_32)) - goto out; - - save_state_to_tss32(vcpu, &tss_segment_32); - - if (kvm_write_guest(vcpu->kvm, old_tss_base, &tss_segment_32, - sizeof tss_segment_32)) - goto out; - - if (kvm_read_guest(vcpu->kvm, get_tss_base_addr_read(vcpu, nseg_desc), - &tss_segment_32, sizeof tss_segment_32)) - goto out; - - if (old_tss_sel != 0xffff) { - tss_segment_32.prev_task_link = old_tss_sel; - - if (kvm_write_guest(vcpu->kvm, - get_tss_base_addr_write(vcpu, nseg_desc), - &tss_segment_32.prev_task_link, - sizeof tss_segment_32.prev_task_link)) - goto out; - } - - if (load_state_from_tss32(vcpu, &tss_segment_32)) - goto out; - - ret = 1; -out: - return ret; -} - int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason) { - struct kvm_segment tr_seg; - struct desc_struct cseg_desc; - struct desc_struct nseg_desc; - int ret = 0; - u32 old_tss_base = get_segment_base(vcpu, VCPU_SREG_TR); - u16 old_tss_sel = get_segment_selector(vcpu, VCPU_SREG_TR); - u32 desc_limit; - - old_tss_base = kvm_mmu_gva_to_gpa_write(vcpu, old_tss_base, NULL); - - /* FIXME: Handle errors. Failure to read either TSS or their - * descriptors should generate a pagefault. - */ - if (load_guest_segment_descriptor(vcpu, tss_selector, &nseg_desc)) - goto out; - - if (load_guest_segment_descriptor(vcpu, old_tss_sel, &cseg_desc)) - goto out; - - if (reason != TASK_SWITCH_IRET) { - int cpl; - - cpl = kvm_x86_ops->get_cpl(vcpu); - if ((tss_selector & 3) > nseg_desc.dpl || cpl > nseg_desc.dpl) { - kvm_queue_exception_e(vcpu, GP_VECTOR, 0); - return 1; - } - } - - desc_limit = get_desc_limit(&nseg_desc); - if (!nseg_desc.p || - ((desc_limit < 0x67 && (nseg_desc.type & 8)) || - desc_limit < 0x2b)) { - kvm_queue_exception_e(vcpu, TS_VECTOR, tss_selector & 0xfffc); - return 1; - } - - if (reason == TASK_SWITCH_IRET || reason == TASK_SWITCH_JMP) { - cseg_desc.type &= ~(1 << 1); //clear the B flag - save_guest_segment_descriptor(vcpu, old_tss_sel, &cseg_desc); - } - - if (reason == TASK_SWITCH_IRET) { - u32 eflags = kvm_get_rflags(vcpu); - kvm_set_rflags(vcpu, eflags & ~X86_EFLAGS_NT); - } + int cs_db, cs_l, ret; + cache_all_regs(vcpu); - /* set back link to prev task only if NT bit is set in eflags - note that old_tss_sel is not used afetr this point */ - if (reason != TASK_SWITCH_CALL && reason != TASK_SWITCH_GATE) - old_tss_sel = 0xffff; + kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l); - if (nseg_desc.type & 8) - ret = kvm_task_switch_32(vcpu, tss_selector, old_tss_sel, - old_tss_base, &nseg_desc); - else - ret = kvm_task_switch_16(vcpu, tss_selector, old_tss_sel, - old_tss_base, &nseg_desc); + vcpu->arch.emulate_ctxt.vcpu = vcpu; + vcpu->arch.emulate_ctxt.eflags = kvm_x86_ops->get_rflags(vcpu); + vcpu->arch.emulate_ctxt.eip = kvm_rip_read(vcpu); + vcpu->arch.emulate_ctxt.mode = + (!is_protmode(vcpu)) ? X86EMUL_MODE_REAL : + (vcpu->arch.emulate_ctxt.eflags & X86_EFLAGS_VM) + ? X86EMUL_MODE_VM86 : cs_l + ? X86EMUL_MODE_PROT64 : cs_db + ? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16; - if (reason == TASK_SWITCH_CALL || reason == TASK_SWITCH_GATE) { - u32 eflags = kvm_get_rflags(vcpu); - kvm_set_rflags(vcpu, eflags | X86_EFLAGS_NT); - } + ret = emulator_task_switch(&vcpu->arch.emulate_ctxt, &emulate_ops, + tss_selector, reason); - if (reason != TASK_SWITCH_IRET) { - nseg_desc.type |= (1 << 1); - save_guest_segment_descriptor(vcpu, tss_selector, - &nseg_desc); - } + if (ret == X86EMUL_CONTINUE) + kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags); - kvm_x86_ops->set_cr0(vcpu, kvm_read_cr0(vcpu) | X86_CR0_TS); - seg_desct_to_kvm_desct(&nseg_desc, tss_selector, &tr_seg); - tr_seg.type = 11; - kvm_set_segment(vcpu, &tr_seg, VCPU_SREG_TR); -out: - return ret; + return (ret != X86EMUL_CONTINUE); } EXPORT_SYMBOL_GPL(kvm_task_switch); -- GitLab