> -----Original Message-----
> From: Vitaly Kuznetsov [mailto:vkuzn...@redhat.com]
> Sent: Tuesday, May 30, 2017 04:34
> To: x...@kernel.org; de...@linuxdriverproject.org
> Cc: linux-kernel@vger.kernel.org; KY Srinivasan <k...@microsoft.com>; Haiyang
> Zhang <haiya...@microsoft.com>; Stephen Hemminger
> <sthem...@microsoft.com>; Thomas Gleixner <t...@linutronix.de>; Ingo
> Molnar <mi...@redhat.com>; H. Peter Anvin <h...@zytor.com>; Steven
> Rostedt <rost...@goodmis.org>; Jork Loeser <jork.loe...@microsoft.com>;
> Simon Xiao <six...@microsoft.com>; Andy Lutomirski <l...@kernel.org>; Andy
> Shevchenko <andy.shevche...@gmail.com>
> Subject: [PATCH v5 09/10] x86/hyper-v: support extended CPU ranges for TLB
> flush hypercalls
>
> Hyper-V hosts may support more than 64 vCPUs, we need to use
> HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX/LIST_EX hypercalls in this case.
> +static inline int cpumask_to_vp_set(struct hv_flush_pcpu_ex *flush,
> + const struct cpumask *cpus)
> +{
> + int cpu, vcpu, vcpu_bank, vcpu_offset, cur_bank, nr_bank = 0;
> + bool has_cpus;
> +
> + /*
> + * We can't be sure that translated vCPU numbers will always be
> + * in ascending order, so iterate over all possible banks and
> + * check all vCPUs in it instead.
> + */
> + for (cur_bank = 0; cur_bank < ms_hyperv.max_vp_index/64;
> cur_bank++) {
> + has_cpus = false;
> + for_each_cpu(cpu, cpus) {
> + vcpu = hv_cpu_number_to_vp_number(cpu);
> + vcpu_bank = vcpu / 64;
> + vcpu_offset = vcpu % 64;
> +
> + if (vcpu_bank != cur_bank)
> + continue;
> + __set_bit(vcpu_offset, (unsigned long *)
> + &flush->hv_vp_set.bank_contents[nr_bank]);
> + if (!has_cpus) {
> + __set_bit(vcpu_bank, (unsigned long *)
> + &flush->hv_vp_set.valid_bank_mask);
> + has_cpus = true;
> + }
> + }
> + if (has_cpus)
> + nr_bank++;
> + }
> +
> + return nr_bank;
> +}
Note that the HV_VP_SET may contain empty banks. As such, consider enabling all
(5) bits in the valid_bank_mask, and a single for_each(cpu, cpus) pass -
setting the bits as per hv_cpu_number_to_vp_number(cpu).
Regards,
Jork
