On Fri, Jan 25, 2019 at 10:46:56AM +0100, Christoffer Dall wrote:
> From: Marc Zyngier <marc.zyngier@xxxxxxx>
>
> Failing to properly reset system registers is pretty bad. But not
> quite as bad as bringing the whole machine down... So warn loudly,
> but slightly more gracefully.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
> Acked-by: Christoffer Dall <christoffer.dall@xxxxxxx>
> ---
> arch/arm/kvm/coproc.c | 4 ++--
> arch/arm64/kvm/sys_regs.c | 4 ++--
> 2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/kvm/coproc.c b/arch/arm/kvm/coproc.c
> index 222c1635bc7a..e8bd288fd5be 100644
> --- a/arch/arm/kvm/coproc.c
> +++ b/arch/arm/kvm/coproc.c
> @@ -1450,6 +1450,6 @@ void kvm_reset_coprocs(struct kvm_vcpu *vcpu)
> reset_coproc_regs(vcpu, table, num);
>
> for (num = 1; num < NR_CP15_REGS; num++)
> - if (vcpu_cp15(vcpu, num) == 0x42424242)
> - panic("Didn't reset vcpu_cp15(vcpu, %zi)", num);
> + WARN(vcpu_cp15(vcpu, num) == 0x42424242,
> + "Didn't reset vcpu_cp15(vcpu, %zi)", num);
> }
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 86096774abcd..4f067545c7d2 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -2609,6 +2609,6 @@ void kvm_reset_sys_regs(struct kvm_vcpu *vcpu)
> reset_sys_reg_descs(vcpu, table, num);
>
> for (num = 1; num < NR_SYS_REGS; num++)
> - if (__vcpu_sys_reg(vcpu, num) == 0x4242424242424242)
> - panic("Didn't reset __vcpu_sys_reg(%zi)", num);
> + WARN(__vcpu_sys_reg(vcpu, num) == 0x4242424242424242,
> + "Didn't reset __vcpu_sys_reg(%zi)\n", num);
> }
> --
> 2.18.0
>
If we only get halfway through resetting, then we'll get a warn splat,
complete with a backtrace, for each register. Should we do something
like the following instead?
for (num = 1; num < NR_SYS_REGS; num++)
if (__vcpu_sys_reg(vcpu, num) == 0x4242424242424242)
failed++;
WARN(failed, "Didn't reset %d system registers", failed);
Thanks,
drew
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