Re: [PATCH v2 9/9] arm: KVM: Treat CP15 accessors returning false as successful

Christoffer Dall
2017-03-28T12:44:19Z

On Mon, Mar 27, 2017 at 05:03:45PM +0100, Marc Zyngier wrote:
> Instead of considering that a CP15 accessor has failed when
> returning false, let's consider that it is *always* successful
> (after all, we won't stand for an incomplete emulation).
>
> The return value now simply indicates whether we should skip
> the instruction (because it has now been emulated), or if we
> should leave the PC alone if the emulation has injected an
> exception.
>

Reviewed-by: Christoffer Dall <cdall@linaro.org>

> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> arch/arm/kvm/coproc.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/kvm/coproc.c b/arch/arm/kvm/coproc.c
> index 519aac12b365..2c14b69511e9 100644
> --- a/arch/arm/kvm/coproc.c
> +++ b/arch/arm/kvm/coproc.c
> @@ -520,15 +520,15 @@ static int emulate_cp15(struct kvm_vcpu *vcpu,
> if (likely(r->access(vcpu, params, r))) {
> /* Skip instruction, since it was emulated */
> kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
> - return 1;
> }
> - /* If access function fails, it should complain. */
> } else {
> + /* If access function fails, it should complain. */
> kvm_err("Unsupported guest CP15 access at: %08lx\n",
> *vcpu_pc(vcpu));
> print_cp_instr(params);
> + kvm_inject_undefined(vcpu);
> }
> - kvm_inject_undefined(vcpu);
> +
> return 1;
> }
>
> --
> 2.11.0
>