From: Sean Christopherson Date: Tue, 2 Nov 2021 09:15:29 +0000 (+0800) Subject: KVM: x86: Handle 32-bit wrap of EIP for EMULTYPE_SKIP with flat code seg X-Git-Tag: v5.15.73~6701 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=3d8468045e39ecb2402b9e54e2d8f5bc6dda5e02;p=platform%2Fkernel%2Flinux-rpi.git KVM: x86: Handle 32-bit wrap of EIP for EMULTYPE_SKIP with flat code seg [ 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 Signed-off-by: Paolo Bonzini Message-Id: <093eabb1eab2965201c9b018373baf26ff256d85.1635842679.git.houwenlong93@linux.alibaba.com> Signed-off-by: Sasha Levin --- diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 33457b27e220..6b76486702de 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;