Not all faults handled by handle_exit are instruction emulations. For example a ESR_ELx_EC_IABT will result in the page tables being updated but the instruction that triggered the fault hasn't actually executed yet. We use the simple heuristic of checking for a changed PC before seeing if kvm_arm_handle_step_debug wants to claim we stepped an instruction.
Signed-off-by: Alex Bennée <[email protected]> --- arch/arm64/kvm/handle_exit.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index e5e741bfffe1..b8252e72f882 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -214,6 +214,7 @@ static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu) static int handle_trap_exceptions(struct kvm_vcpu *vcpu, struct kvm_run *run) { int handled; + unsigned long old_pc = *vcpu_pc(vcpu); /* * See ARM ARM B1.14.1: "Hyp traps on instructions @@ -233,7 +234,8 @@ static int handle_trap_exceptions(struct kvm_vcpu *vcpu, struct kvm_run *run) * kvm_arm_handle_step_debug() sets the exit_reason on the kvm_run * structure if we need to return to userspace. */ - if (handled > 0 && kvm_arm_handle_step_debug(vcpu, run)) + if (handled > 0 && *vcpu_pc(vcpu) != old_pc && + kvm_arm_handle_step_debug(vcpu, run)) handled = 0; return handled; -- 2.17.1 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
