This patch fixes emulate_syscall(), emulate_sysenter() and
emulate_sysexit() to handle injected faults properly.
Even though original code injects faults in these functions,
we cannot handle these unless we use the different return
value from the UNHANDLEABLE case. So this patch use X86EMUL_*
codes instead of -1 and 0 and makes x86_emulate_insn() to
handle these propagated faults.
Be sure that, in x86_emulate_insn(), goto cannot_emulate and
goto done with rc equals X86EMUL_UNHANDLEABLE have same effect.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@xxxxxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 43 +++++++++++++++++++++++--------------------
1 files changed, 23 insertions(+), 20 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index a4e44ca..ddec1c5 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1512,7 +1512,7 @@ emulate_syscall(struct x86_emulate_ctxt *ctxt)
/* syscall is not available in real mode */
if (c->lock_prefix || ctxt->mode == X86EMUL_MODE_REAL
|| !is_protmode(ctxt->vcpu))
- return -1;
+ return X86EMUL_UNHANDLEABLE;
setup_syscalls_segments(ctxt, &cs, &ss);
@@ -1549,7 +1549,7 @@ emulate_syscall(struct x86_emulate_ctxt *ctxt)
ctxt->eflags &= ~(EFLG_VM | EFLG_IF | EFLG_RF);
}
- return 0;
+ return X86EMUL_CONTINUE;
}
static int
@@ -1561,19 +1561,19 @@ emulate_sysenter(struct x86_emulate_ctxt *ctxt)
/* inject #UD if LOCK prefix is used */
if (c->lock_prefix)
- return -1;
+ return X86EMUL_UNHANDLEABLE;
/* inject #GP if in real mode or paging is disabled */
if (ctxt->mode == X86EMUL_MODE_REAL || !is_protmode(ctxt->vcpu)) {
kvm_inject_gp(ctxt->vcpu, 0);
- return -1;
+ return X86EMUL_PROPAGATE_FAULT;
}
/* XXX sysenter/sysexit have not been tested in 64bit mode.
* Therefore, we inject an #UD.
*/
if (ctxt->mode == X86EMUL_MODE_PROT64)
- return -1;
+ return X86EMUL_UNHANDLEABLE;
setup_syscalls_segments(ctxt, &cs, &ss);
@@ -1582,13 +1582,13 @@ emulate_sysenter(struct x86_emulate_ctxt *ctxt)
case X86EMUL_MODE_PROT32:
if ((msr_data & 0xfffc) == 0x0) {
kvm_inject_gp(ctxt->vcpu, 0);
- return -1;
+ return X86EMUL_PROPAGATE_FAULT;
}
break;
case X86EMUL_MODE_PROT64:
if (msr_data == 0x0) {
kvm_inject_gp(ctxt->vcpu, 0);
- return -1;
+ return X86EMUL_PROPAGATE_FAULT;
}
break;
}
@@ -1613,7 +1613,7 @@ emulate_sysenter(struct x86_emulate_ctxt *ctxt)
kvm_x86_ops->get_msr(ctxt->vcpu, MSR_IA32_SYSENTER_ESP, &msr_data);
c->regs[VCPU_REGS_RSP] = msr_data;
- return 0;
+ return X86EMUL_CONTINUE;
}
static int
@@ -1626,18 +1626,18 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt)
/* inject #UD if LOCK prefix is used */
if (c->lock_prefix)
- return -1;
+ return X86EMUL_UNHANDLEABLE;
/* inject #GP if in real mode or paging is disabled */
if (ctxt->mode == X86EMUL_MODE_REAL || !is_protmode(ctxt->vcpu)) {
kvm_inject_gp(ctxt->vcpu, 0);
- return -1;
+ return X86EMUL_PROPAGATE_FAULT;
}
/* sysexit must be called from CPL 0 */
if (kvm_x86_ops->get_cpl(ctxt->vcpu) != 0) {
kvm_inject_gp(ctxt->vcpu, 0);
- return -1;
+ return X86EMUL_PROPAGATE_FAULT;
}
setup_syscalls_segments(ctxt, &cs, &ss);
@@ -1655,7 +1655,7 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt)
cs.selector = (u16)(msr_data + 16);
if ((msr_data & 0xfffc) == 0x0) {
kvm_inject_gp(ctxt->vcpu, 0);
- return -1;
+ return X86EMUL_PROPAGATE_FAULT;
}
ss.selector = (u16)(msr_data + 24);
break;
@@ -1663,7 +1663,7 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt)
cs.selector = (u16)(msr_data + 32);
if (msr_data == 0x0) {
kvm_inject_gp(ctxt->vcpu, 0);
- return -1;
+ return X86EMUL_PROPAGATE_FAULT;
}
ss.selector = cs.selector + 8;
cs.db = 0;
@@ -1679,7 +1679,7 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt)
c->eip = ctxt->vcpu->arch.regs[VCPU_REGS_RDX];
c->regs[VCPU_REGS_RSP] = ctxt->vcpu->arch.regs[VCPU_REGS_RCX];
- return 0;
+ return X86EMUL_CONTINUE;
}
int
@@ -2318,8 +2318,9 @@ twobyte_insn:
}
break;
case 0x05: /* syscall */
- if (emulate_syscall(ctxt) == -1)
- goto cannot_emulate;
+ rc = emulate_syscall(ctxt);
+ if (rc != X86EMUL_CONTINUE)
+ goto done;
else
goto writeback;
break;
@@ -2387,14 +2388,16 @@ twobyte_insn:
c->dst.type = OP_NONE;
break;
case 0x34: /* sysenter */
- if (emulate_sysenter(ctxt) == -1)
- goto cannot_emulate;
+ rc = emulate_sysenter(ctxt);
+ if (rc != X86EMUL_CONTINUE)
+ goto done;
else
goto writeback;
break;
case 0x35: /* sysexit */
- if (emulate_sysexit(ctxt) == -1)
- goto cannot_emulate;
+ rc = emulate_sysexit(ctxt);
+ if (rc != X86EMUL_CONTINUE)
+ goto done;
else
goto writeback;
break;
--
1.6.3.3
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