KVM: x86: Push potential exception error code on task switches
When a fault triggers a task switch, the error code, if existent, has to
be pushed on the new task's stack. Implement the missing bits.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index aace565..585d0ef 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2344,8 +2344,9 @@
}
static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt,
- struct x86_emulate_ops *ops,
- u16 tss_selector, int reason)
+ struct x86_emulate_ops *ops,
+ u16 tss_selector, int reason,
+ bool has_error_code, u32 error_code)
{
struct desc_struct curr_tss_desc, next_tss_desc;
int ret;
@@ -2418,12 +2419,22 @@
ops->set_cached_descriptor(&next_tss_desc, VCPU_SREG_TR, ctxt->vcpu);
ops->set_segment_selector(tss_selector, VCPU_SREG_TR, ctxt->vcpu);
+ if (has_error_code) {
+ struct decode_cache *c = &ctxt->decode;
+
+ c->op_bytes = c->ad_bytes = (next_tss_desc.type & 8) ? 4 : 2;
+ c->lock_prefix = 0;
+ c->src.val = (unsigned long) error_code;
+ emulate_push(ctxt);
+ }
+
return ret;
}
int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
- u16 tss_selector, int reason)
+ u16 tss_selector, int reason,
+ bool has_error_code, u32 error_code)
{
struct decode_cache *c = &ctxt->decode;
int rc;
@@ -2431,12 +2442,15 @@
memset(c, 0, sizeof(struct decode_cache));
c->eip = ctxt->eip;
memcpy(c->regs, ctxt->vcpu->arch.regs, sizeof c->regs);
+ c->dst.type = OP_NONE;
- rc = emulator_do_task_switch(ctxt, ops, tss_selector, reason);
+ rc = emulator_do_task_switch(ctxt, ops, tss_selector, reason,
+ has_error_code, error_code);
if (rc == X86EMUL_CONTINUE) {
memcpy(ctxt->vcpu->arch.regs, c->regs, sizeof c->regs);
kvm_rip_write(ctxt->vcpu, c->eip);
+ rc = writeback(ctxt, ops);
}
return rc;