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-rw-r--r--arch/x86/include/asm/kvm_host.h3
-rw-r--r--arch/x86/kvm/emulate.c30
-rw-r--r--arch/x86/kvm/x86.c177
3 files changed, 151 insertions, 59 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f9a2f66530c..06d9e79ca37 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -614,8 +614,7 @@ int emulator_set_dr(struct x86_emulate_ctxt *ctxt, int dr,
unsigned long value);
void kvm_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg);
-int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector,
- int type_bits, int seg);
+int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, int seg);
int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason);
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 2db760ff887..a1a7b27adf4 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1309,7 +1309,7 @@ static int emulate_pop_sreg(struct x86_emulate_ctxt *ctxt,
if (rc != 0)
return rc;
- rc = kvm_load_segment_descriptor(ctxt->vcpu, (u16)selector, 1, seg);
+ rc = kvm_load_segment_descriptor(ctxt->vcpu, (u16)selector, seg);
return rc;
}
@@ -1491,7 +1491,7 @@ static int emulate_ret_far(struct x86_emulate_ctxt *ctxt,
rc = emulate_pop(ctxt, ops, &cs, c->op_bytes);
if (rc)
return rc;
- rc = kvm_load_segment_descriptor(ctxt->vcpu, (u16)cs, 1, VCPU_SREG_CS);
+ rc = kvm_load_segment_descriptor(ctxt->vcpu, (u16)cs, VCPU_SREG_CS);
return rc;
}
@@ -2122,12 +2122,11 @@ special_insn:
break;
case 0x8e: { /* mov seg, r/m16 */
uint16_t sel;
- int type_bits;
- int err;
sel = c->src.val;
- if (c->modrm_reg == VCPU_SREG_CS) {
+ if (c->modrm_reg == VCPU_SREG_CS ||
+ c->modrm_reg > VCPU_SREG_GS) {
kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
goto done;
}
@@ -2135,18 +2134,7 @@ special_insn:
if (c->modrm_reg == VCPU_SREG_SS)
toggle_interruptibility(ctxt, X86_SHADOW_INT_MOV_SS);
- if (c->modrm_reg <= 5) {
- type_bits = (c->modrm_reg == 1) ? 9 : 1;
- err = kvm_load_segment_descriptor(ctxt->vcpu, sel,
- type_bits, c->modrm_reg);
- } else {
- printk(KERN_INFO "Invalid segreg in modrm byte 0x%02x\n",
- c->modrm);
- goto cannot_emulate;
- }
-
- if (err < 0)
- goto cannot_emulate;
+ rc = kvm_load_segment_descriptor(ctxt->vcpu, sel, c->modrm_reg);
c->dst.type = OP_NONE; /* Disable writeback. */
break;
@@ -2320,11 +2308,9 @@ special_insn:
case 0xe9: /* jmp rel */
goto jmp;
case 0xea: /* jmp far */
- if (kvm_load_segment_descriptor(ctxt->vcpu, c->src2.val, 9,
- VCPU_SREG_CS) < 0) {
- DPRINTF("jmp far: Failed to load CS descriptor\n");
- goto cannot_emulate;
- }
+ if (kvm_load_segment_descriptor(ctxt->vcpu, c->src2.val,
+ VCPU_SREG_CS))
+ goto done;
c->eip = c->src.val;
break;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 203ee7d0ed5..c3d2acbbb91 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4787,7 +4787,7 @@ static int kvm_load_realmode_segment(struct kvm_vcpu *vcpu, u16 selector, int se
.unusable = 0,
};
kvm_x86_ops->set_segment(vcpu, &segvar, seg);
- return 0;
+ return X86EMUL_CONTINUE;
}
static int is_vm86_segment(struct kvm_vcpu *vcpu, int seg)
@@ -4797,43 +4797,112 @@ static int is_vm86_segment(struct kvm_vcpu *vcpu, int seg)
(kvm_get_rflags(vcpu) & X86_EFLAGS_VM);
}
-static void kvm_check_segment_descriptor(struct kvm_vcpu *vcpu, int seg,
- u16 selector)
-{
- /* NULL selector is not valid for CS and SS */
- if (seg == VCPU_SREG_CS || seg == VCPU_SREG_SS)
- if (!selector)
- kvm_queue_exception_e(vcpu, TS_VECTOR, selector >> 3);
-}
-
-int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector,
- int type_bits, int seg)
+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);
- if (load_guest_segment_descriptor(vcpu, selector, &seg_desc))
- return 1;
+ /* 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);
- kvm_check_segment_descriptor(vcpu, seg, selector);
- kvm_seg.type |= type_bits;
+ if (null_selector) { /* for NULL selector skip all following checks */
+ kvm_seg.unusable = 1;
+ goto load;
+ }
- if (seg != VCPU_SREG_SS && seg != VCPU_SREG_CS &&
- seg != VCPU_SREG_LDTR)
- if (!kvm_seg.s)
- kvm_seg.unusable = 1;
+ err_code = selector & 0xfffc;
+ err_vec = GP_VECTOR;
- kvm_set_segment(vcpu, &kvm_seg, seg);
- if (selector && !kvm_seg.unusable && kvm_seg.s) {
+ /* 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);
}
- return 0;
+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,
@@ -4859,6 +4928,14 @@ static void save_state_to_tss32(struct kvm_vcpu *vcpu,
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)
{
@@ -4876,25 +4953,41 @@ static int load_state_from_tss32(struct kvm_vcpu *vcpu,
kvm_register_write(vcpu, VCPU_REGS_RSI, tss->esi);
kvm_register_write(vcpu, VCPU_REGS_RDI, tss->edi);
- if (kvm_load_segment_descriptor(vcpu, tss->ldt_selector, 0, VCPU_SREG_LDTR))
+ /*
+ * 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, 1, VCPU_SREG_ES))
+ if (kvm_load_segment_descriptor(vcpu, tss->es, VCPU_SREG_ES))
return 1;
- if (kvm_load_segment_descriptor(vcpu, tss->cs, 9, VCPU_SREG_CS))
+ if (kvm_load_segment_descriptor(vcpu, tss->cs, VCPU_SREG_CS))
return 1;
- if (kvm_load_segment_descriptor(vcpu, tss->ss, 1, VCPU_SREG_SS))
+ if (kvm_load_segment_descriptor(vcpu, tss->ss, VCPU_SREG_SS))
return 1;
- if (kvm_load_segment_descriptor(vcpu, tss->ds, 1, VCPU_SREG_DS))
+ if (kvm_load_segment_descriptor(vcpu, tss->ds, VCPU_SREG_DS))
return 1;
- if (kvm_load_segment_descriptor(vcpu, tss->fs, 1, VCPU_SREG_FS))
+ if (kvm_load_segment_descriptor(vcpu, tss->fs, VCPU_SREG_FS))
return 1;
- if (kvm_load_segment_descriptor(vcpu, tss->gs, 1, VCPU_SREG_GS))
+ if (kvm_load_segment_descriptor(vcpu, tss->gs, VCPU_SREG_GS))
return 1;
return 0;
}
@@ -4934,19 +5027,33 @@ static int load_state_from_tss16(struct kvm_vcpu *vcpu,
kvm_register_write(vcpu, VCPU_REGS_RSI, tss->si);
kvm_register_write(vcpu, VCPU_REGS_RDI, tss->di);
- if (kvm_load_segment_descriptor(vcpu, tss->ldt, 0, VCPU_SREG_LDTR))
+ /*
+ * 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, 1, VCPU_SREG_ES))
+ if (kvm_load_segment_descriptor(vcpu, tss->es, VCPU_SREG_ES))
return 1;
- if (kvm_load_segment_descriptor(vcpu, tss->cs, 9, VCPU_SREG_CS))
+ if (kvm_load_segment_descriptor(vcpu, tss->cs, VCPU_SREG_CS))
return 1;
- if (kvm_load_segment_descriptor(vcpu, tss->ss, 1, VCPU_SREG_SS))
+ if (kvm_load_segment_descriptor(vcpu, tss->ss, VCPU_SREG_SS))
return 1;
- if (kvm_load_segment_descriptor(vcpu, tss->ds, 1, VCPU_SREG_DS))
+ if (kvm_load_segment_descriptor(vcpu, tss->ds, VCPU_SREG_DS))
return 1;
return 0;
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-22 21:10:52 +0000