Messages in this thread | | | From | Jork Loeser <> | Subject | RE: [PATCH v5 09/10] x86/hyper-v: support extended CPU ranges for TLB flush hypercalls | Date | Tue, 30 May 2017 19:13:23 +0000 |
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> -----Original Message----- > From: Vitaly Kuznetsov [mailto:vkuznets@redhat.com] > Sent: Tuesday, May 30, 2017 04:34 > To: x86@kernel.org; devel@linuxdriverproject.org > Cc: linux-kernel@vger.kernel.org; KY Srinivasan <kys@microsoft.com>; Haiyang > Zhang <haiyangz@microsoft.com>; Stephen Hemminger > <sthemmin@microsoft.com>; Thomas Gleixner <tglx@linutronix.de>; Ingo > Molnar <mingo@redhat.com>; H. Peter Anvin <hpa@zytor.com>; Steven > Rostedt <rostedt@goodmis.org>; Jork Loeser <Jork.Loeser@microsoft.com>; > Simon Xiao <sixiao@microsoft.com>; Andy Lutomirski <luto@kernel.org>; Andy > Shevchenko <andy.shevchenko@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
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