This patch differentiate the X86EMUL_* values returned from
X86EMUL_* type functions.
Note: During this work, we noticed some buggy return value
checks in x86_emulate_insn(). See FIXME in this patch.
Signed-off-by: Takuya Yoshikawa <yoshikawa.tak...@oss.ntt.co.jp>
---
arch/x86/kvm/emulate.c | 73 +++++++++++++++++++++++++++++-------------------
1 files changed, 44 insertions(+), 29 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 9953f5b..d49e9de 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1693,7 +1693,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct
x86_emulate_ops *ops)
struct decode_cache *c = &ctxt->decode;
unsigned int port;
int io_dir_in;
- int rc = 0;
+ int rc = X86EMUL_CONTINUE;
ctxt->interruptibility = 0;
@@ -1791,7 +1791,7 @@ special_insn:
break;
case 0x07: /* pop es */
rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_ES);
- if (rc != 0)
+ if (rc != X86EMUL_CONTINUE)
goto done;
break;
case 0x08 ... 0x0d:
@@ -1810,7 +1810,7 @@ special_insn:
break;
case 0x17: /* pop ss */
rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_SS);
- if (rc != 0)
+ if (rc != X86EMUL_CONTINUE)
goto done;
break;
case 0x18 ... 0x1d:
@@ -1822,7 +1822,7 @@ special_insn:
break;
case 0x1f: /* pop ds */
rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_DS);
- if (rc != 0)
+ if (rc != X86EMUL_CONTINUE)
goto done;
break;
case 0x20 ... 0x25:
@@ -1853,7 +1853,7 @@ special_insn:
case 0x58 ... 0x5f: /* pop reg */
pop_instruction:
rc = emulate_pop(ctxt, ops, &c->dst.val, c->op_bytes);
- if (rc != 0)
+ if (rc != X86EMUL_CONTINUE)
goto done;
break;
case 0x60: /* pusha */
@@ -1861,7 +1861,7 @@ special_insn:
break;
case 0x61: /* popa */
rc = emulate_popa(ctxt, ops);
- if (rc != 0)
+ if (rc != X86EMUL_CONTINUE)
goto done;
break;
case 0x63: /* movsxd */
@@ -2002,7 +2002,7 @@ special_insn:
}
case 0x8f: /* pop (sole member of Grp1a) */
rc = emulate_grp1a(ctxt, ops);
- if (rc != 0)
+ if (rc != X86EMUL_CONTINUE)
goto done;
break;
case 0x90: /* nop / xchg r8,rax */
@@ -2135,7 +2135,7 @@ special_insn:
break;
case 0xcb: /* ret far */
rc = emulate_ret_far(ctxt, ops);
- if (rc)
+ if (rc != X86EMUL_CONTINUE)
goto done;
break;
case 0xd0 ... 0xd1: /* Grp2 */
@@ -2205,7 +2205,7 @@ special_insn:
break;
case 0xf6 ... 0xf7: /* Grp3 */
rc = emulate_grp3(ctxt, ops);
- if (rc != 0)
+ if (rc != X86EMUL_CONTINUE)
goto done;
break;
case 0xf8: /* clc */
@@ -2231,14 +2231,14 @@ special_insn:
break;
case 0xfe ... 0xff: /* Grp4/Grp5 */
rc = emulate_grp45(ctxt, ops);
- if (rc != 0)
+ if (rc != X86EMUL_CONTINUE)
goto done;
break;
}
writeback:
rc = writeback(ctxt, ops);
- if (rc != 0)
+ if (rc != X86EMUL_CONTINUE)
goto done;
/* Commit shadow register state. */
@@ -2263,8 +2263,18 @@ twobyte_insn:
if (c->modrm_mod != 3 || c->modrm_rm != 1)
goto cannot_emulate;
- rc = kvm_fix_hypercall(ctxt->vcpu);
- if (rc)
+ /* FIXME:
+ * kvm_fix_hypercall() calls emulator_write_emulated()
+ * and if the return value is not X86EMUL_CONTINUE then
+ * returns -EFAULT, otherwise returns X86EMUL_CONTINUE.
+ *
+ * To handle the former case, original code just did
+ * goto done with rc = -EFAULT and passed the
+ * if (X86EMUL_UNHANDLEABLE) check.
+ * Instead of this, we just set rc to X86EMUL_CONTINUE.
+ */
+ rc = X86EMUL_CONTINUE;
+ if (kvm_fix_hypercall(ctxt->vcpu))
goto done;
/* Let the processor re-execute the fixed hypercall */
@@ -2275,7 +2285,7 @@ twobyte_insn:
case 2: /* lgdt */
rc = read_descriptor(ctxt, ops, c->src.ptr,
&size, &address, c->op_bytes);
- if (rc)
+ if (rc != X86EMUL_CONTINUE)
goto done;
realmode_lgdt(ctxt->vcpu, size, address);
/* Disable writeback. */
@@ -2285,8 +2295,9 @@ twobyte_insn:
if (c->modrm_mod == 3) {
switch (c->modrm_rm) {
case 1:
- rc = kvm_fix_hypercall(ctxt->vcpu);
- if (rc)
+ /* FIXME: See above */
+ rc = X86EMUL_CONTINUE;
+ if (kvm_fix_hypercall(ctxt->vcpu))
goto done;
break;
default:
@@ -2296,7 +2307,7 @@ twobyte_insn:
rc = read_descriptor(ctxt, ops, c->src.ptr,
&size, &address,
c->op_bytes);
- if (rc)
+ if (rc != X86EMUL_CONTINUE)
goto done;
realmode_lidt(ctxt->vcpu, size, address);
}
@@ -2347,9 +2358,12 @@ twobyte_insn:
case 0x21: /* mov from dr to reg */
if (c->modrm_mod != 3)
goto cannot_emulate;
- rc = emulator_get_dr(ctxt, c->modrm_reg, &c->regs[c->modrm_rm]);
- if (rc)
+ if (emulator_get_dr(ctxt, c->modrm_reg, &c->regs[c->modrm_rm]))
goto cannot_emulate;
+ /* FIXME: Next line is just for ensuring to pass
+ * the if (rc != X86EMUL_UNHANDLEABLE) test.
+ */
+ rc = X86EMUL_CONTINUE;
c->dst.type = OP_NONE; /* no writeback */
break;
case 0x22: /* mov reg, cr */
@@ -2362,18 +2376,19 @@ twobyte_insn:
case 0x23: /* mov from reg to dr */
if (c->modrm_mod != 3)
goto cannot_emulate;
- rc = emulator_set_dr(ctxt, c->modrm_reg,
- c->regs[c->modrm_rm]);
- if (rc)
+ if (emulator_set_dr(ctxt, c->modrm_reg, c->regs[c->modrm_rm]))
goto cannot_emulate;
+ /* FIXME: Next line is just for ensuring to pass
+ * the if (rc != X86EMUL_UNHANDLEABLE) test.
+ */
+ rc = X86EMUL_CONTINUE;
c->dst.type = OP_NONE; /* no writeback */
break;
case 0x30:
/* wrmsr */
msr_data = (u32)c->regs[VCPU_REGS_RAX]
| ((u64)c->regs[VCPU_REGS_RDX] << 32);
- rc = kvm_set_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], msr_data);
- if (rc) {
+ if (kvm_set_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], msr_data)) {
kvm_inject_gp(ctxt->vcpu, 0);
c->eip = kvm_rip_read(ctxt->vcpu);
}
@@ -2382,8 +2397,8 @@ twobyte_insn:
break;
case 0x32:
/* rdmsr */
- rc = kvm_get_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], &msr_data);
- if (rc) {
+ if (kvm_get_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX],
+ &msr_data)) {
kvm_inject_gp(ctxt->vcpu, 0);
c->eip = kvm_rip_read(ctxt->vcpu);
} else {
@@ -2420,7 +2435,7 @@ twobyte_insn:
break;
case 0xa1: /* pop fs */
rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_FS);
- if (rc != 0)
+ if (rc != X86EMUL_CONTINUE)
goto done;
break;
case 0xa3:
@@ -2439,7 +2454,7 @@ twobyte_insn:
break;
case 0xa9: /* pop gs */
rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_GS);
- if (rc != 0)
+ if (rc != X86EMUL_CONTINUE)
goto done;
break;
case 0xab:
@@ -2512,7 +2527,7 @@ twobyte_insn:
break;
case 0xc7: /* Grp9 (cmpxchg8b) */
rc = emulate_grp9(ctxt, ops, memop);
- if (rc != 0)
+ if (rc != X86EMUL_CONTINUE)
goto done;
c->dst.type = OP_NONE;
break;
--
1.6.3.3
--
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