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KVM: x86 emulator: do not inject exception directly into vcpu

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Return exception as a result of instruction emulation and handle
injection in KVM code.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Gleb Natapov 2010-04-28 19:15:44 +03:00 committed by Avi Kivity
parent 95cb229530
commit 54b8486f46
3 changed files with 100 additions and 50 deletions
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6
arch/x86/include/asm/kvm_emulate.h
View File

@ -216,6 +216,12 @@ struct x86_emulate_ctxt {
int interruptibility;
bool restart; /* restart string instruction after writeback */
int exception; /* exception that happens during emulation or -1 */
u32 error_code; /* error code for exception */
bool error_code_valid;
unsigned long cr2; /* faulted address in case of #PF */
/* decode cache */
struct decode_cache decode;
};

124
arch/x86/kvm/emulate.c
View File

@ -653,6 +653,37 @@ static unsigned long ss_base(struct x86_emulate_ctxt *ctxt,
return seg_base(ctxt, ops, VCPU_SREG_SS);
}
static void emulate_exception(struct x86_emulate_ctxt *ctxt, int vec,
u32 error, bool valid)
{
ctxt->exception = vec;
ctxt->error_code = error;
ctxt->error_code_valid = valid;
ctxt->restart = false;
}
static void emulate_gp(struct x86_emulate_ctxt *ctxt, int err)
{
emulate_exception(ctxt, GP_VECTOR, err, true);
}
static void emulate_pf(struct x86_emulate_ctxt *ctxt, unsigned long addr,
int err)
{
ctxt->cr2 = addr;
emulate_exception(ctxt, PF_VECTOR, err, true);
}
static void emulate_ud(struct x86_emulate_ctxt *ctxt)
{
emulate_exception(ctxt, UD_VECTOR, 0, false);
}
static void emulate_ts(struct x86_emulate_ctxt *ctxt, int err)
{
emulate_exception(ctxt, TS_VECTOR, err, true);
}
static int do_fetch_insn_byte(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
unsigned long eip, u8 *dest)
@ -1285,7 +1316,7 @@ static int read_emulated(struct x86_emulate_ctxt *ctxt,
rc = ops->read_emulated(addr, mc->data + mc->end, n, &err,
ctxt->vcpu);
if (rc == X86EMUL_PROPAGATE_FAULT)
kvm_inject_page_fault(ctxt->vcpu, addr, err);
emulate_pf(ctxt, addr, err);
if (rc != X86EMUL_CONTINUE)
return rc;
mc->end += n;
@ -1366,13 +1397,13 @@ static int read_segment_descriptor(struct x86_emulate_ctxt *ctxt,
get_descriptor_table_ptr(ctxt, ops, selector, &dt);
if (dt.size < index * 8 + 7) {
kvm_inject_gp(ctxt->vcpu, selector & 0xfffc);
emulate_gp(ctxt, selector & 0xfffc);
return X86EMUL_PROPAGATE_FAULT;
}
addr = dt.address + index * 8;
ret = ops->read_std(addr, desc, sizeof *desc, ctxt->vcpu, &err);
if (ret == X86EMUL_PROPAGATE_FAULT)
kvm_inject_page_fault(ctxt->vcpu, addr, err);
emulate_pf(ctxt, addr, err);
return ret;
}
@ -1391,14 +1422,14 @@ static int write_segment_descriptor(struct x86_emulate_ctxt *ctxt,
get_descriptor_table_ptr(ctxt, ops, selector, &dt);
if (dt.size < index * 8 + 7) {
kvm_inject_gp(ctxt->vcpu, selector & 0xfffc);
emulate_gp(ctxt, selector & 0xfffc);
return X86EMUL_PROPAGATE_FAULT;
}
addr = dt.address + index * 8;
ret = ops->write_std(addr, desc, sizeof *desc, ctxt->vcpu, &err);
if (ret == X86EMUL_PROPAGATE_FAULT)
kvm_inject_page_fault(ctxt->vcpu, addr, err);
emulate_pf(ctxt, addr, err);
return ret;
}
@ -1517,7 +1548,7 @@ load:
ops->set_cached_descriptor(&seg_desc, seg, ctxt->vcpu);
return X86EMUL_CONTINUE;
exception:
kvm_queue_exception_e(ctxt->vcpu, err_vec, err_code);
emulate_exception(ctxt, err_vec, err_code, true);
return X86EMUL_PROPAGATE_FAULT;
}
@ -1578,7 +1609,7 @@ static int emulate_popf(struct x86_emulate_ctxt *ctxt,
break;
case X86EMUL_MODE_VM86:
if (iopl < 3) {
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
return X86EMUL_PROPAGATE_FAULT;
}
change_mask |= EFLG_IF;
@ -1829,7 +1860,7 @@ static inline int writeback(struct x86_emulate_ctxt *ctxt,
&err,
ctxt->vcpu);
if (rc == X86EMUL_PROPAGATE_FAULT)
kvm_inject_page_fault(ctxt->vcpu,
emulate_pf(ctxt,
(unsigned long)c->dst.ptr, err);
if (rc != X86EMUL_CONTINUE)
return rc;
@ -1883,7 +1914,7 @@ emulate_syscall(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
/* syscall is not available in real mode */
if (ctxt->mode == X86EMUL_MODE_REAL ||
ctxt->mode == X86EMUL_MODE_VM86) {
kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
emulate_ud(ctxt);
return X86EMUL_PROPAGATE_FAULT;
}
@ -1937,7 +1968,7 @@ emulate_sysenter(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
/* inject #GP if in real mode */
if (ctxt->mode == X86EMUL_MODE_REAL) {
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
return X86EMUL_PROPAGATE_FAULT;
}
@ -1945,7 +1976,7 @@ emulate_sysenter(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
* Therefore, we inject an #UD.
*/
if (ctxt->mode == X86EMUL_MODE_PROT64) {
kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
emulate_ud(ctxt);
return X86EMUL_PROPAGATE_FAULT;
}
@ -1955,13 +1986,13 @@ emulate_sysenter(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
switch (ctxt->mode) {
case X86EMUL_MODE_PROT32:
if ((msr_data & 0xfffc) == 0x0) {
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
return X86EMUL_PROPAGATE_FAULT;
}
break;
case X86EMUL_MODE_PROT64:
if (msr_data == 0x0) {
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
return X86EMUL_PROPAGATE_FAULT;
}
break;
@ -2004,7 +2035,7 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
/* inject #GP if in real mode or Virtual 8086 mode */
if (ctxt->mode == X86EMUL_MODE_REAL ||
ctxt->mode == X86EMUL_MODE_VM86) {
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
return X86EMUL_PROPAGATE_FAULT;
}
@ -2022,7 +2053,7 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
case X86EMUL_MODE_PROT32:
cs_sel = (u16)(msr_data + 16);
if ((msr_data & 0xfffc) == 0x0) {
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
return X86EMUL_PROPAGATE_FAULT;
}
ss_sel = (u16)(msr_data + 24);
@ -2030,7 +2061,7 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
case X86EMUL_MODE_PROT64:
cs_sel = (u16)(msr_data + 32);
if (msr_data == 0x0) {
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
return X86EMUL_PROPAGATE_FAULT;
}
ss_sel = cs_sel + 8;
@ -2192,7 +2223,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
&err);
if (ret == X86EMUL_PROPAGATE_FAULT) {
/* FIXME: need to provide precise fault address */
kvm_inject_page_fault(ctxt->vcpu, old_tss_base, err);
emulate_pf(ctxt, old_tss_base, err);
return ret;
}
@ -2202,7 +2233,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
&err);
if (ret == X86EMUL_PROPAGATE_FAULT) {
/* FIXME: need to provide precise fault address */
kvm_inject_page_fault(ctxt->vcpu, old_tss_base, err);
emulate_pf(ctxt, old_tss_base, err);
return ret;
}
@ -2210,7 +2241,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
&err);
if (ret == X86EMUL_PROPAGATE_FAULT) {
/* FIXME: need to provide precise fault address */
kvm_inject_page_fault(ctxt->vcpu, new_tss_base, err);
emulate_pf(ctxt, new_tss_base, err);
return ret;
}
@ -2223,7 +2254,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
ctxt->vcpu, &err);
if (ret == X86EMUL_PROPAGATE_FAULT) {
/* FIXME: need to provide precise fault address */
kvm_inject_page_fault(ctxt->vcpu, new_tss_base, err);
emulate_pf(ctxt, new_tss_base, err);
return ret;
}
}
@ -2266,7 +2297,7 @@ static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt,
int ret;
if (ops->set_cr(3, tss->cr3, ctxt->vcpu)) {
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
return X86EMUL_PROPAGATE_FAULT;
}
c->eip = tss->eip;
@ -2334,7 +2365,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
&err);
if (ret == X86EMUL_PROPAGATE_FAULT) {
/* FIXME: need to provide precise fault address */
kvm_inject_page_fault(ctxt->vcpu, old_tss_base, err);
emulate_pf(ctxt, old_tss_base, err);
return ret;
}
@ -2344,7 +2375,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
&err);
if (ret == X86EMUL_PROPAGATE_FAULT) {
/* FIXME: need to provide precise fault address */
kvm_inject_page_fault(ctxt->vcpu, old_tss_base, err);
emulate_pf(ctxt, old_tss_base, err);
return ret;
}
@ -2352,7 +2383,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
&err);
if (ret == X86EMUL_PROPAGATE_FAULT) {
/* FIXME: need to provide precise fault address */
kvm_inject_page_fault(ctxt->vcpu, new_tss_base, err);
emulate_pf(ctxt, new_tss_base, err);
return ret;
}
@ -2365,7 +2396,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
ctxt->vcpu, &err);
if (ret == X86EMUL_PROPAGATE_FAULT) {
/* FIXME: need to provide precise fault address */
kvm_inject_page_fault(ctxt->vcpu, new_tss_base, err);
emulate_pf(ctxt, new_tss_base, err);
return ret;
}
}
@ -2399,7 +2430,7 @@ static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt,
if (reason != TASK_SWITCH_IRET) {
if ((tss_selector & 3) > next_tss_desc.dpl ||
ops->cpl(ctxt->vcpu) > next_tss_desc.dpl) {
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
return X86EMUL_PROPAGATE_FAULT;
}
}
@ -2408,8 +2439,7 @@ static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt,
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);
emulate_ts(ctxt, tss_selector & 0xfffc);
return X86EMUL_PROPAGATE_FAULT;
}
@ -2505,19 +2535,19 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
ctxt->decode.mem_read.pos = 0;
if (ctxt->mode == X86EMUL_MODE_PROT64 && (c->d & No64)) {
kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
emulate_ud(ctxt);
goto done;
}
/* LOCK prefix is allowed only with some instructions */
if (c->lock_prefix && (!(c->d & Lock) || c->dst.type != OP_MEM)) {
kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
emulate_ud(ctxt);
goto done;
}
/* Privileged instruction can be executed only in CPL=0 */
if ((c->d & Priv) && ops->cpl(ctxt->vcpu)) {
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
goto done;
}
@ -2679,7 +2709,7 @@ special_insn:
c->dst.bytes = min(c->dst.bytes, 4u);
if (!emulator_io_permited(ctxt, ops, c->regs[VCPU_REGS_RDX],
c->dst.bytes)) {
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
goto done;
}
if (!pio_in_emulated(ctxt, ops, c->dst.bytes,
@ -2691,7 +2721,7 @@ special_insn:
c->src.bytes = min(c->src.bytes, 4u);
if (!emulator_io_permited(ctxt, ops, c->regs[VCPU_REGS_RDX],
c->src.bytes)) {
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
goto done;
}
ops->pio_out_emulated(c->src.bytes, c->regs[VCPU_REGS_RDX],
@ -2754,7 +2784,7 @@ special_insn:
goto mov;
case 0x8c: /* mov r/m, sreg */
if (c->modrm_reg > VCPU_SREG_GS) {
kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
emulate_ud(ctxt);
goto done;
}
c->dst.val = ops->get_segment_selector(c->modrm_reg, ctxt->vcpu);
@ -2769,7 +2799,7 @@ special_insn:
if (c->modrm_reg == VCPU_SREG_CS ||
c->modrm_reg > VCPU_SREG_GS) {
kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
emulate_ud(ctxt);
goto done;
}
@ -2895,7 +2925,7 @@ special_insn:
do_io_in:
c->dst.bytes = min(c->dst.bytes, 4u);
if (!emulator_io_permited(ctxt, ops, c->src.val, c->dst.bytes)) {
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
goto done;
}
if (!pio_in_emulated(ctxt, ops, c->dst.bytes, c->src.val,
@ -2908,7 +2938,7 @@ special_insn:
do_io_out:
c->dst.bytes = min(c->dst.bytes, 4u);
if (!emulator_io_permited(ctxt, ops, c->src.val, c->dst.bytes)) {
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
goto done;
}
ops->pio_out_emulated(c->dst.bytes, c->src.val, &c->dst.val, 1,
@ -2933,7 +2963,7 @@ special_insn:
break;
case 0xfa: /* cli */
if (emulator_bad_iopl(ctxt, ops))
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
else {
ctxt->eflags &= ~X86_EFLAGS_IF;
c->dst.type = OP_NONE; /* Disable writeback. */
@ -2941,7 +2971,7 @@ special_insn:
break;
case 0xfb: /* sti */
if (emulator_bad_iopl(ctxt, ops))
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
else {
ctxt->interruptibility = KVM_X86_SHADOW_INT_STI;
ctxt->eflags |= X86_EFLAGS_IF;
@ -3069,7 +3099,7 @@ twobyte_insn:
c->dst.type = OP_NONE;
break;
case 5: /* not defined */
kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
emulate_ud(ctxt);
goto done;
case 7: /* invlpg*/
emulate_invlpg(ctxt->vcpu, c->modrm_ea);
@ -3102,7 +3132,7 @@ twobyte_insn:
case 1:
case 5 ... 7:
case 9 ... 15:
kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
emulate_ud(ctxt);
goto done;
}
c->regs[c->modrm_rm] = ops->get_cr(c->modrm_reg, ctxt->vcpu);
@ -3111,7 +3141,7 @@ twobyte_insn:
case 0x21: /* mov from dr to reg */
if ((ops->get_cr(4, ctxt->vcpu) & X86_CR4_DE) &&
(c->modrm_reg == 4 || c->modrm_reg == 5)) {
kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
emulate_ud(ctxt);
goto done;
}
ops->get_dr(c->modrm_reg, &c->regs[c->modrm_rm], ctxt->vcpu);
@ -3119,7 +3149,7 @@ twobyte_insn:
break;
case 0x22: /* mov reg, cr */
if (ops->set_cr(c->modrm_reg, c->modrm_val, ctxt->vcpu)) {
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
goto done;
}
c->dst.type = OP_NONE;
@ -3127,7 +3157,7 @@ twobyte_insn:
case 0x23: /* mov from reg to dr */
if ((ops->get_cr(4, ctxt->vcpu) & X86_CR4_DE) &&
(c->modrm_reg == 4 || c->modrm_reg == 5)) {
kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
emulate_ud(ctxt);
goto done;
}
@ -3135,7 +3165,7 @@ twobyte_insn:
((ctxt->mode == X86EMUL_MODE_PROT64) ?
~0ULL : ~0U), ctxt->vcpu) < 0) {
/* #UD condition is already handled by the code above */
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
goto done;
}
@ -3146,7 +3176,7 @@ twobyte_insn:
msr_data = (u32)c->regs[VCPU_REGS_RAX]
| ((u64)c->regs[VCPU_REGS_RDX] << 32);
if (ops->set_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], msr_data)) {
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
goto done;
}
rc = X86EMUL_CONTINUE;
@ -3155,7 +3185,7 @@ twobyte_insn:
case 0x32:
/* rdmsr */
if (ops->get_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], &msr_data)) {
kvm_inject_gp(ctxt->vcpu, 0);
emulate_gp(ctxt, 0);
goto done;
} else {
c->regs[VCPU_REGS_RAX] = (u32)msr_data;

20
arch/x86/kvm/x86.c
View File

@ -3852,6 +3852,17 @@ static void toggle_interruptibility(struct kvm_vcpu *vcpu, u32 mask)
kvm_x86_ops->set_interrupt_shadow(vcpu, mask);
}
static void inject_emulated_exception(struct kvm_vcpu *vcpu)
{
struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
if (ctxt->exception == PF_VECTOR)
kvm_inject_page_fault(vcpu, ctxt->cr2, ctxt->error_code);
else if (ctxt->error_code_valid)
kvm_queue_exception_e(vcpu, ctxt->exception, ctxt->error_code);
else
kvm_queue_exception(vcpu, ctxt->exception);
}
int emulate_instruction(struct kvm_vcpu *vcpu,
unsigned long cr2,
u16 error_code,
@ -3886,6 +3897,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
memset(c, 0, sizeof(struct decode_cache));
memcpy(c->regs, vcpu->arch.regs, sizeof c->regs);
vcpu->arch.emulate_ctxt.interruptibility = 0;
vcpu->arch.emulate_ctxt.exception = -1;
r = x86_decode_insn(&vcpu->arch.emulate_ctxt, &emulate_ops);
trace_kvm_emulate_insn_start(vcpu);
@ -3958,6 +3970,11 @@ restart:
memcpy(vcpu->arch.regs, c->regs, sizeof c->regs);
kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.eip);
if (vcpu->arch.emulate_ctxt.exception >= 0) {
inject_emulated_exception(vcpu);
return EMULATE_DONE;
}
if (vcpu->arch.pio.count) {
if (!vcpu->arch.pio.in)
vcpu->arch.pio.count = 0;
@ -3970,9 +3987,6 @@ restart:
return EMULATE_DO_MMIO;
}
if (vcpu->arch.exception.pending)
vcpu->arch.emulate_ctxt.restart = false;
if (vcpu->arch.emulate_ctxt.restart)
goto restart;