The commit is pushed to "branch-rh7-3.10.0-957.27.2.vz7.107.x-ovz" and will
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-957.27.2.vz7.107.13
------>
commit 0233d7fda444bf90759fcaec1dbd810c2298eb1d
Author: Jan Dakinevich <[email protected]>
Date: Thu Oct 3 15:03:47 2019 +0300
ms/KVM: x86: set ctxt->have_exception in x86_decode_insn()
x86_emulate_instruction() takes into account ctxt->have_exception flag
during instruction decoding, but in practice this flag is never set in
x86_decode_insn().
Fixes: 6ea6e84309ca ("KVM: x86: inject exceptions produced by
x86_decode_insn")
Cc: [email protected]
Cc: Denis Lunev <[email protected]>
Cc: Roman Kagan <[email protected]>
Cc: Denis Plotnikov <[email protected]>
Signed-off-by: Jan Dakinevich <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
https://jira.sw.ru/browse/PSBM-68018
(cherry-picked from c8848cee74ff05638e913582a476bde879c968ad)
=====================
Patchset description:
fix emulation error on Windows bootup
This series intended to fix (again) a bug that was a subject of the
following change:
6ea6e84 ("KVM: x86: inject exceptions produced by x86_decode_insn")
Suddenly, that fix had a couple mistakes. First, ctxt->have_exception was
not set if fault happened during instruction decoding. Second, returning
value of inject_emulated_instruction was used to make the decision to
reenter guest, but this could happen iff on nested page fault, that is not
the scope where this bug could occur.
https://lkml.org/lkml/2019/8/29/152
Jan Dakinevich (2):
KVM: x86: always stop emulation on page fault
KVM: x86: set ctxt->have_exception in x86_decode_insn()
Paolo Bonzini (1):
KVM: x86: inject exceptions produced by x86_decode_insn
---
arch/x86/kvm/emulate.c | 2 ++
arch/x86/kvm/x86.c | 6 ++++++
2 files changed, 8 insertions(+)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 94898cd05857..93d2203a7942 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -5311,6 +5311,8 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void
*insn, int insn_len)
ctxt->memopp->addr.mem.ea + ctxt->_eip);
done:
+ if (rc == X86EMUL_PROPAGATE_FAULT)
+ ctxt->have_exception = true;
return (rc != X86EMUL_CONTINUE) ? EMULATION_FAILED : EMULATION_OK;
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8ed5b23ff055..980d469f3f63 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5760,6 +5760,12 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu,
emulation_type))
return EMULATE_DONE;
if (ctxt->have_exception) {
+ /*
+ * #UD should result in just EMULATION_FAILED,
and trap-like
+ * exception should not be encountered during
decode.
+ */
+ WARN_ON_ONCE(ctxt->exception.vector ==
UD_VECTOR ||
+
exception_type(ctxt->exception.vector) == EXCPT_TRAP);
inject_emulated_exception(vcpu);
return EMULATE_DONE;
}
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