From 5c9cfc48663606f26455e4113fd5a1f29b19ddc9 Mon Sep 17 00:00:00 2001 From: Ivan Orlov Date: Tue, 17 Dec 2024 18:14:53 +0000 Subject: [PATCH] KVM: x86: Add emulation status for unhandleable exception vectoring Add emulation status for unhandleable vectoring, i.e. when KVM can't emulate an instruction because emulation was triggered on an exit that occurred while the CPU was vectoring an event. Such a situation can occur if guest sets the IDT descriptor base to point to MMIO region, and triggers an exception after that. Exit to userspace with event delivery error when KVM can't emulate an instruction when vectoring an event. Signed-off-by: Ivan Orlov Link: https://lore.kernel.org/r/20241217181458.68690-3-iorlov@amazon.com [sean: massage changelog and X86EMUL_UNHANDLEABLE_VECTORING comment] Signed-off-by: Sean Christopherson --- arch/x86/kvm/kvm_emulate.h | 2 ++ arch/x86/kvm/x86.c | 5 +++++ 2 files changed, 7 insertions(+) diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h index 10495fffb890..73072585e164 100644 --- a/arch/x86/kvm/kvm_emulate.h +++ b/arch/x86/kvm/kvm_emulate.h @@ -88,6 +88,8 @@ struct x86_instruction_info { #define X86EMUL_CMPXCHG_FAILED 4 /* cmpxchg did not see expected value */ #define X86EMUL_IO_NEEDED 5 /* IO is needed to complete emulation */ #define X86EMUL_INTERCEPTED 6 /* Intercepted by nested VMCB/VMCS */ +/* Emulation during event vectoring is unhandleable. */ +#define X86EMUL_UNHANDLEABLE_VECTORING 7 /* x86-specific emulation flags */ #define X86EMUL_F_WRITE BIT(0) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 7fcdfafb25a2..26dd74512b67 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9098,6 +9098,11 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, if (r == X86EMUL_RETRY_INSTR || r == X86EMUL_PROPAGATE_FAULT) return 1; + if (r == X86EMUL_UNHANDLEABLE_VECTORING) { + kvm_prepare_event_vectoring_exit(vcpu, cr2_or_gpa); + return 0; + } + WARN_ON_ONCE(r != X86EMUL_UNHANDLEABLE); return handle_emulation_failure(vcpu, emulation_type); } -- 2.25.1