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e0685fa228
Enable paravirtualization features when running under a hypervisor supporting the PV_TIME_ST hypercall. For each (v)CPU, we ask the hypervisor for the location of a shared page which the hypervisor will use to report stolen time to us. We set pv_time_ops to the stolen time function which simply reads the stolen value from the shared page for a VCPU. We guarantee single-copy atomicity using READ_ONCE which means we can also read the stolen time for another VCPU than the currently running one while it is potentially being updated by the hypervisor. Signed-off-by: Steven Price <steven.price@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
33 lines
628 B
C
33 lines
628 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_ARM64_PARAVIRT_H
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#define _ASM_ARM64_PARAVIRT_H
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#ifdef CONFIG_PARAVIRT
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struct static_key;
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extern struct static_key paravirt_steal_enabled;
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extern struct static_key paravirt_steal_rq_enabled;
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struct pv_time_ops {
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unsigned long long (*steal_clock)(int cpu);
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};
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struct paravirt_patch_template {
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struct pv_time_ops time;
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};
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extern struct paravirt_patch_template pv_ops;
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static inline u64 paravirt_steal_clock(int cpu)
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{
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return pv_ops.time.steal_clock(cpu);
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}
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int __init pv_time_init(void);
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#else
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#define pv_time_init() do {} while (0)
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#endif // CONFIG_PARAVIRT
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#endif
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