KVM: x86: Add kvm_skip_emulated_instruction and use it.
kvm_skip_emulated_instruction calls both kvm_x86_ops->skip_emulated_instruction and kvm_vcpu_check_singlestep, skipping the emulated instruction and generating a trap if necessary. Replacing skip_emulated_instruction calls with kvm_skip_emulated_instruction is straightforward, except for: - ICEBP, which is already inside a trap, so avoid triggering another trap. - Instructions that can trigger exits to userspace, such as the IO insns, MOVs to CR8, and HALT. If kvm_skip_emulated_instruction does trigger a KVM_GUESTDBG_SINGLESTEP exit, and the handling code for IN/OUT/MOV CR8/HALT also triggers an exit to userspace, the latter will take precedence. The singlestep will be triggered again on the next instruction, which is the current behavior. - Task switch instructions which would require additional handling (e.g. the task switch bit) and are instead left alone. - Cases where VMLAUNCH/VMRESUME do not proceed to the next instruction, which do not trigger singlestep traps as mentioned previously. Signed-off-by:Kyle Huey <khuey@kylehuey.com> Signed-off-by:
Radim Krčmář <rkrcmar@redhat.com>
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