This patch is the second part of a work which tries to split
x86_emulate_insn() into a few meaningful functions: just encapsulates
the switch statement for the two byte instruction emulation as
emulate_twobyte_insn().
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@xxxxxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 286 ++++++++++++++++++++++++++----------------------
1 files changed, 153 insertions(+), 133 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 18d7c07..7aa93df 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3309,142 +3309,14 @@ cannot_emulate:
return X86EMUL_UNHANDLEABLE;
}
-int
-x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
+static int emulate_twobyte_insn(struct x86_emulate_ctxt *ctxt,
+ struct x86_emulate_ops *ops,
+ struct decode_cache *c,
+ bool *need_writeback)
{
- struct x86_emulate_ops *ops = ctxt->ops;
- u64 msr_data;
- struct decode_cache *c = &ctxt->decode;
int rc = X86EMUL_CONTINUE;
- int saved_dst_type = c->dst.type;
- bool need_writeback;
-
- ctxt->decode.mem_read.pos = 0;
-
- if (ctxt->mode == X86EMUL_MODE_PROT64 && (c->d & No64)) {
- rc = 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)) {
- rc = emulate_ud(ctxt);
- goto done;
- }
-
- if ((c->d & SrcMask) == SrcMemFAddr && c->src.type != OP_MEM) {
- rc = emulate_ud(ctxt);
- goto done;
- }
-
- /* Privileged instruction can be executed only in CPL=0 */
- if ((c->d & Priv) && ops->cpl(ctxt->vcpu)) {
- rc = emulate_gp(ctxt, 0);
- goto done;
- }
-
- if (c->rep_prefix && (c->d & String)) {
- /* All REP prefixes have the same first termination condition */
- if (address_mask(c, c->regs[VCPU_REGS_RCX]) == 0) {
- ctxt->eip = c->eip;
- goto done;
- }
- }
-
- if ((c->src.type == OP_MEM) && !(c->d & NoAccess)) {
- rc = read_emulated(ctxt, ops, linear(ctxt, c->src.addr.mem),
- c->src.valptr, c->src.bytes);
- if (rc != X86EMUL_CONTINUE)
- goto done;
- c->src.orig_val64 = c->src.val64;
- }
-
- if (c->src2.type == OP_MEM) {
- rc = read_emulated(ctxt, ops, linear(ctxt, c->src2.addr.mem),
- &c->src2.val, c->src2.bytes);
- if (rc != X86EMUL_CONTINUE)
- goto done;
- }
-
- if ((c->d & DstMask) == ImplicitOps)
- goto special_insn;
-
-
- if ((c->dst.type == OP_MEM) && !(c->d & Mov)) {
- /* optimisation - avoid slow emulated read if Mov */
- rc = read_emulated(ctxt, ops, linear(ctxt, c->dst.addr.mem),
- &c->dst.val, c->dst.bytes);
- if (rc != X86EMUL_CONTINUE)
- goto done;
- }
- c->dst.orig_val = c->dst.val;
-
-special_insn:
-
- if (c->execute) {
- rc = c->execute(ctxt);
- if (rc != X86EMUL_CONTINUE)
- goto done;
- goto writeback;
- }
-
- if (c->twobyte)
- goto twobyte_insn;
-
- rc = emulate_onebyte_insn(ctxt, ops, c, &need_writeback);
- if (!need_writeback)
- goto done;
-
-writeback:
- rc = writeback(ctxt, ops);
- if (rc != X86EMUL_CONTINUE)
- goto done;
-
- /*
- * restore dst type in case the decoding will be reused
- * (happens for string instruction )
- */
- c->dst.type = saved_dst_type;
-
- if ((c->d & SrcMask) == SrcSI)
- string_addr_inc(ctxt, seg_override(ctxt, ops, c),
- VCPU_REGS_RSI, &c->src);
-
- if ((c->d & DstMask) == DstDI)
- string_addr_inc(ctxt, VCPU_SREG_ES, VCPU_REGS_RDI,
- &c->dst);
-
- if (c->rep_prefix && (c->d & String)) {
- struct read_cache *r = &ctxt->decode.io_read;
- register_address_increment(c, &c->regs[VCPU_REGS_RCX], -1);
-
- if (!string_insn_completed(ctxt)) {
- /*
- * Re-enter guest when pio read ahead buffer is empty
- * or, if it is not used, after each 1024 iteration.
- */
- if ((r->end != 0 || c->regs[VCPU_REGS_RCX] & 0x3ff) &&
- (r->end == 0 || r->end != r->pos)) {
- /*
- * Reset read cache. Usually happens before
- * decode, but since instruction is restarted
- * we have to do it here.
- */
- ctxt->decode.mem_read.end = 0;
- return EMULATION_RESTART;
- }
- goto done; /* skip rip writeback */
- }
- }
-
- ctxt->eip = c->eip;
-
-done:
- if (rc == X86EMUL_PROPAGATE_FAULT)
- ctxt->have_exception = true;
- return (rc == X86EMUL_UNHANDLEABLE) ? EMULATION_FAILED : EMULATION_OK;
+ u64 msr_data;
-twobyte_insn:
switch (c->b) {
case 0x01: /* lgdt, lidt, lmsw */
switch (c->modrm_reg) {
@@ -3748,9 +3620,157 @@ twobyte_insn:
goto cannot_emulate;
}
+ *need_writeback = (rc == X86EMUL_CONTINUE);
+ return rc;
+
+done:
+ *need_writeback = false;
+ return rc;
+
+cannot_emulate:
+ *need_writeback = false;
+ return X86EMUL_UNHANDLEABLE;
+}
+
+int
+x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
+{
+ struct x86_emulate_ops *ops = ctxt->ops;
+ struct decode_cache *c = &ctxt->decode;
+ int rc = X86EMUL_CONTINUE;
+ int saved_dst_type = c->dst.type;
+ bool need_writeback;
+
+ ctxt->decode.mem_read.pos = 0;
+
+ if (ctxt->mode == X86EMUL_MODE_PROT64 && (c->d & No64)) {
+ rc = 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)) {
+ rc = emulate_ud(ctxt);
+ goto done;
+ }
+
+ if ((c->d & SrcMask) == SrcMemFAddr && c->src.type != OP_MEM) {
+ rc = emulate_ud(ctxt);
+ goto done;
+ }
+
+ /* Privileged instruction can be executed only in CPL=0 */
+ if ((c->d & Priv) && ops->cpl(ctxt->vcpu)) {
+ rc = emulate_gp(ctxt, 0);
+ goto done;
+ }
+
+ if (c->rep_prefix && (c->d & String)) {
+ /* All REP prefixes have the same first termination condition */
+ if (address_mask(c, c->regs[VCPU_REGS_RCX]) == 0) {
+ ctxt->eip = c->eip;
+ goto done;
+ }
+ }
+
+ if ((c->src.type == OP_MEM) && !(c->d & NoAccess)) {
+ rc = read_emulated(ctxt, ops, linear(ctxt, c->src.addr.mem),
+ c->src.valptr, c->src.bytes);
+ if (rc != X86EMUL_CONTINUE)
+ goto done;
+ c->src.orig_val64 = c->src.val64;
+ }
+
+ if (c->src2.type == OP_MEM) {
+ rc = read_emulated(ctxt, ops, linear(ctxt, c->src2.addr.mem),
+ &c->src2.val, c->src2.bytes);
+ if (rc != X86EMUL_CONTINUE)
+ goto done;
+ }
+
+ if ((c->d & DstMask) == ImplicitOps)
+ goto special_insn;
+
+
+ if ((c->dst.type == OP_MEM) && !(c->d & Mov)) {
+ /* optimisation - avoid slow emulated read if Mov */
+ rc = read_emulated(ctxt, ops, linear(ctxt, c->dst.addr.mem),
+ &c->dst.val, c->dst.bytes);
+ if (rc != X86EMUL_CONTINUE)
+ goto done;
+ }
+ c->dst.orig_val = c->dst.val;
+
+special_insn:
+
+ if (c->execute) {
+ rc = c->execute(ctxt);
+ if (rc != X86EMUL_CONTINUE)
+ goto done;
+ goto writeback;
+ }
+
+ if (c->twobyte)
+ goto twobyte_insn;
+
+ rc = emulate_onebyte_insn(ctxt, ops, c, &need_writeback);
+ if (!need_writeback)
+ goto done;
+
+writeback:
+ rc = writeback(ctxt, ops);
if (rc != X86EMUL_CONTINUE)
goto done;
+ /*
+ * restore dst type in case the decoding will be reused
+ * (happens for string instruction )
+ */
+ c->dst.type = saved_dst_type;
+
+ if ((c->d & SrcMask) == SrcSI)
+ string_addr_inc(ctxt, seg_override(ctxt, ops, c),
+ VCPU_REGS_RSI, &c->src);
+
+ if ((c->d & DstMask) == DstDI)
+ string_addr_inc(ctxt, VCPU_SREG_ES, VCPU_REGS_RDI,
+ &c->dst);
+
+ if (c->rep_prefix && (c->d & String)) {
+ struct read_cache *r = &ctxt->decode.io_read;
+ register_address_increment(c, &c->regs[VCPU_REGS_RCX], -1);
+
+ if (!string_insn_completed(ctxt)) {
+ /*
+ * Re-enter guest when pio read ahead buffer is empty
+ * or, if it is not used, after each 1024 iteration.
+ */
+ if ((r->end != 0 || c->regs[VCPU_REGS_RCX] & 0x3ff) &&
+ (r->end == 0 || r->end != r->pos)) {
+ /*
+ * Reset read cache. Usually happens before
+ * decode, but since instruction is restarted
+ * we have to do it here.
+ */
+ ctxt->decode.mem_read.end = 0;
+ return EMULATION_RESTART;
+ }
+ goto done; /* skip rip writeback */
+ }
+ }
+
+ ctxt->eip = c->eip;
+
+done:
+ if (rc == X86EMUL_PROPAGATE_FAULT)
+ ctxt->have_exception = true;
+ return (rc == X86EMUL_UNHANDLEABLE) ? EMULATION_FAILED : EMULATION_OK;
+
+twobyte_insn:
+ rc = emulate_twobyte_insn(ctxt, ops, c, &need_writeback);
+ if (!need_writeback)
+ goto done;
+
goto writeback;
cannot_emulate:
--
1.7.1
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