From: Sean Christopherson seanjc@google.com
[ Upstream commit 5e854864ee4384736f27a986633bae21731a4e4e ]
Truncate the new EIP to a 32-bit value when handling EMULTYPE_SKIP as the decode phase does not truncate _eip. Wrapping the 32-bit boundary is legal if and only if CS is a flat code segment, but that check is implicitly handled in the form of limit checks in the decode phase.
Opportunstically prepare for a future fix by storing the result of any truncation in "eip" instead of "_eip".
Fixes: 1957aa63be53 ("KVM: VMX: Handle single-step #DB for EMULTYPE_SKIP on EPT misconfig") Signed-off-by: Sean Christopherson seanjc@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Message-Id: 093eabb1eab2965201c9b018373baf26ff256d85.1635842679.git.houwenlong93@linux.alibaba.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/kvm/x86.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 33457b27e220b..6b76486702ded 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7999,7 +7999,12 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, * updating interruptibility state and injecting single-step #DBs. */ if (emulation_type & EMULTYPE_SKIP) { - kvm_rip_write(vcpu, ctxt->_eip); + if (ctxt->mode != X86EMUL_MODE_PROT64) + ctxt->eip = (u32)ctxt->_eip; + else + ctxt->eip = ctxt->_eip; + + kvm_rip_write(vcpu, ctxt->eip); if (ctxt->eflags & X86_EFLAGS_RF) kvm_set_rflags(vcpu, ctxt->eflags & ~X86_EFLAGS_RF); return 1;