[PATCH v3 04/13] KVM: x86: emulator: update the emulation mode after rsm

[Maxim Levitsky]

This ensures that RIP will be correctly written back,
because the RSM instruction can switch the CPU mode from
32 bit (or less) to 64 bit.

This fixes a guest crash in case the #SMI is received
while the guest runs a code from an address > 32 bit.

Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
---
 arch/x86/kvm/emulate.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index bc70caf403c2b4..5e91b26cc1d8aa 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2666,6 +2666,11 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt)
 	if (ret != X86EMUL_CONTINUE)
 		goto emulate_shutdown;
 
+
+	ret = emulator_recalc_and_set_mode(ctxt);
+	if (ret != X86EMUL_CONTINUE)
+		goto emulate_shutdown;
+
 	/*
 	 * Note, the ctxt->ops callbacks are responsible for handling side
 	 * effects when writing MSRs and CRs, e.g. MMU context resets, CPUID
-- 
2.26.3