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yaml
---
r: 186078
b: refs/heads/master
c: c697518
h: refs/heads/master
v: v3
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Gleb Natapov authored and Marcelo Tosatti committed Mar 1, 2010
1 parent 2e4f537 commit 5a0a2d5
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Showing 4 changed files with 152 additions and 60 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 6f550484a15ea1b468665cdf59f020bf08ccb292
refs/heads/master: c697518a861e6c43b92b848895f9926580ee63c3
3 changes: 1 addition & 2 deletions trunk/arch/x86/include/asm/kvm_host.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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);

Expand Down
30 changes: 8 additions & 22 deletions trunk/arch/x86/kvm/emulate.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
}

Expand Down Expand Up @@ -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;
}

Expand Down Expand Up @@ -2122,31 +2122,19 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
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;
}

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;
Expand Down Expand Up @@ -2320,11 +2308,9 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
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;
Expand Down
177 changes: 142 additions & 35 deletions trunk/arch/x86/kvm/x86.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand All @@ -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,
Expand All @@ -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)
{
Expand All @@ -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;
}
Expand Down Expand Up @@ -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;
}
Expand Down

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