On Fri, Feb 05, 2016 at 03:14:01PM +0800, Shannon Zhao wrote:
> From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
>
> Add access handler which gets host value of PMCEID0 or PMCEID1 when
> guest access these registers. Writing action to PMCEID0 or PMCEID1 is
> UNDEFINED.
>
> Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> ---
> arch/arm64/kvm/sys_regs.c | 29 +++++++++++++++++++++++++----
> 1 file changed, 25 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index fc60041..06257e2 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -492,6 +492,27 @@ static bool access_pmselr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> return true;
> }
>
> +static bool access_pmceid(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> + const struct sys_reg_desc *r)
> +{
> + u64 pmceid;
> +
> + if (!kvm_arm_pmu_v3_ready(vcpu))
> + return trap_raz_wi(vcpu, p, r);
> +
> + if (p->is_write)
> + return false;
Isn't it really a BUG_ON(p->is_write) ?
Presumably a guest write to these registers will raise an undefined
exception in EL0/1 and we don't get here by any other path than the trap
handler, do we?
Otherwise looks good to me.
Thanks,
-Christoffer
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