diff options
| author | Sean Christopherson <[email protected]> | 2024-08-02 12:51:18 -0700 |
|---|---|---|
| committer | Sean Christopherson <[email protected]> | 2024-08-29 19:50:21 -0700 |
| commit | f7f39c50edb9d336274371953275e0d3503b9b75 (patch) | |
| tree | 995de606a2daba4cfeb408cc89a3806eff92eaa2 | |
| parent | ea60229af7fbdcdd06d798f8340a7a9b40770c53 (diff) | |
KVM: x86: Exit to userspace if fastpath triggers one on instruction skip
Exit to userspace if a fastpath handler triggers such an exit, which can
happen when skipping the instruction, e.g. due to userspace
single-stepping the guest via KVM_GUESTDBG_SINGLESTEP or because of an
emulation failure.
Fixes: 404d5d7bff0d ("KVM: X86: Introduce more exit_fastpath_completion enum values")
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sean Christopherson <[email protected]>
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 1 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 9 |
2 files changed, 8 insertions, 2 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index f9dfb2d62053..430a0d369322 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -211,6 +211,7 @@ enum exit_fastpath_completion { EXIT_FASTPATH_NONE, EXIT_FASTPATH_REENTER_GUEST, EXIT_FASTPATH_EXIT_HANDLED, + EXIT_FASTPATH_EXIT_USERSPACE, }; typedef enum exit_fastpath_completion fastpath_t; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index d392e9097d63..d6c81d59d487 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2206,8 +2206,10 @@ fastpath_t handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu) } if (handled) { - kvm_skip_emulated_instruction(vcpu); - ret = EXIT_FASTPATH_REENTER_GUEST; + if (!kvm_skip_emulated_instruction(vcpu)) + ret = EXIT_FASTPATH_EXIT_USERSPACE; + else + ret = EXIT_FASTPATH_REENTER_GUEST; trace_kvm_msr_write(msr, data); } else { ret = EXIT_FASTPATH_NONE; @@ -11196,6 +11198,9 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) if (vcpu->arch.apic_attention) kvm_lapic_sync_from_vapic(vcpu); + if (unlikely(exit_fastpath == EXIT_FASTPATH_EXIT_USERSPACE)) + return 0; + r = kvm_x86_call(handle_exit)(vcpu, exit_fastpath); return r; |