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[v4,10/23] KVM: x86: emulator: em_sysexit should update ctxt->mode

Message ID 20221025124223.227577-11-mlevitsk@redhat.com
State Accepted
Commit 5015bb89b58225f97df6ac44383e7e8c8662c8c9
Headers show
Series SMM emulation and interrupt shadow fixes | expand

Commit Message

Maxim Levitsky Oct. 25, 2022, 12:42 p.m. UTC 
SYSEXIT is one of the instructions that can change the
processor mode, thus ctxt->mode should be updated after it.

Note that this is likely a benign bug, because the only problematic
mode change is from 32 bit to 64 bit which can lead to truncation of RIP,
and it is not possible to do with sysexit,
since sysexit running in 32 bit mode will be limited to 32 bit version.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 arch/x86/kvm/emulate.c | 1 +
 1 file changed, 1 insertion(+)
diff mbox series

Patch

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 671f7e5871ff70..e23c984d6aae09 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2525,6 +2525,7 @@  static int em_sysexit(struct x86_emulate_ctxt *ctxt)
 	ops->set_segment(ctxt, ss_sel, &ss, 0, VCPU_SREG_SS);
 
 	ctxt->_eip = rdx;
+	ctxt->mode = usermode;
 	*reg_write(ctxt, VCPU_REGS_RSP) = rcx;
 
 	return X86EMUL_CONTINUE;