When handling ept misconfig exit, it will call emulate instruction with insn_len = 0. The decode instruction function may return a fetch fault and should propagate to guest. The problem will result to emulation fail. KVM internal error. Suberror: 1 emulation failure EAX=f81a0024 EBX=f6a07000 ECX=f6a0737c EDX=f8be0118 ESI=f6a0737c EDI=00000021 EBP=f6929f98 ESP=f6929f98 EIP=f8bdd141 EFL=00010086 [--S--P-] CPL=0 II=0 A20=1 SMM=0 HLT=0 ES =007b 00000000 ffffffff 00c0f300 DPL=3 DS [-WA] CS =0060 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA] SS =0068 00000000 ffffffff 00c09300 DPL=0 DS [-WA] DS =007b 00000000 ffffffff 00c0f300 DPL=3 DS [-WA] FS =00d8 2c044000 ffffffff 00809300 DPL=0 DS16 [-WA] GS =0033 081a44c8 01000fff 00d0f300 DPL=3 DS [-WA] LDT=0000 00000000 ffffffff 00000000 TR =0080 f6ea0c80 0000206b 00008b00 DPL=0 TSS32-busy GDT= f6e99000 000000ff IDT= fffbb000 000007ff CR0=80050033 CR2=b757d000 CR3=35d31000 CR4=001406d0 Signed-off-by: Peng Hao <peng.hao2@xxxxxxxxxx> --- arch/x86/kvm/emulate.c | 5 ++++- arch/x86/kvm/x86.c | 4 +++- 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 78e430f..dd132cf 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -5114,8 +5114,11 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) memcpy(ctxt->fetch.data, insn, insn_len); else { rc = __do_insn_fetch_bytes(ctxt, 1); - if (rc != X86EMUL_CONTINUE) + if (rc != X86EMUL_CONTINUE) { + if (rc == X86EMUL_PROPAGATE_FAULT) + ctxt->have_exception = true; return rc; + } } switch (mode) { diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index f049ecf..137d384 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6333,8 +6333,10 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, if (reexecute_instruction(vcpu, cr2, write_fault_to_spt, emulation_type)) return EMULATE_DONE; - if (ctxt->have_exception && inject_emulated_exception(vcpu)) + if (ctxt->have_exception) { + inject_emulated_exception(vcpu); return EMULATE_DONE; + } if (emulation_type & EMULTYPE_SKIP) return EMULATE_FAIL; return handle_emulation_failure(vcpu, emulation_type); -- 1.8.3.1