[PATCH v2 04/11] KVM: x86: emulator: update the emulation mode after rsm

Maxim Levitsky
2022-06-21T15:09:41Z

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@redhat.com>
---
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 334a06e6c9b093..6f4632babc4cd8 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2662,6 +2662,11 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt)
if (ret != X86EMUL_CONTINUE)
goto emulate_shutdown;

+
+ ret = update_emulation_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