105 lines
2.3 KiB
C
105 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2012-2015 - ARM Ltd
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* Author: Marc Zyngier <[email protected]>
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*/
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#include <clocksource/arm_arch_timer.h>
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#include <linux/compiler.h>
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#include <linux/kvm_host.h>
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#include <asm/kvm_hyp.h>
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#include <asm/kvm_mmu.h>
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#include <nvhe/pkvm.h>
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static u32 timer_freq;
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void __kvm_timer_set_cntvoff(u64 cntvoff)
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{
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write_sysreg(cntvoff, cntvoff_el2);
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}
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/*
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* Should only be called on non-VHE or hVHE setups.
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* VHE systems use EL2 timers and configure EL1 timers in kvm_timer_init_vhe().
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*/
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void __timer_disable_traps(struct kvm_vcpu *vcpu)
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{
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u64 val, shift = 0;
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if (has_hvhe())
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shift = 10;
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/* Allow physical timer/counter access for the host */
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val = read_sysreg(cnthctl_el2);
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val |= (CNTHCTL_EL1PCTEN | CNTHCTL_EL1PCEN) << shift;
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write_sysreg(val, cnthctl_el2);
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}
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/*
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* Should only be called on non-VHE or hVHE setups.
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* VHE systems use EL2 timers and configure EL1 timers in kvm_timer_init_vhe().
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*/
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void __timer_enable_traps(struct kvm_vcpu *vcpu)
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{
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u64 clr = 0, set = 0;
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/*
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* Disallow physical timer access for the guest
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* Physical counter access is allowed if no offset is enforced
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* or running protected (we don't offset anything in this case).
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*/
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clr = CNTHCTL_EL1PCEN;
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if (is_protected_kvm_enabled() ||
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!kern_hyp_va(vcpu->kvm)->arch.timer_data.poffset)
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set |= CNTHCTL_EL1PCTEN;
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else
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clr |= CNTHCTL_EL1PCTEN;
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if (has_hvhe()) {
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clr <<= 10;
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set <<= 10;
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}
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sysreg_clear_set(cnthctl_el2, clr, set);
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}
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static u64 pkvm_ticks_get(void)
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{
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return __arch_counter_get_cntvct();
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}
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#define SEC_TO_US 1000000
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int pkvm_timer_init(void)
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{
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timer_freq = read_sysreg(cntfrq_el0);
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/*
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* TODO: The highest privileged level is supposed to initialize this
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* register. But on some systems (which?), this information is only
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* contained in the device-tree, so we'll need to find it out some other
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* way.
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*/
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if (!timer_freq || timer_freq < SEC_TO_US)
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return -ENODEV;
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return 0;
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}
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#define pkvm_time_us_to_ticks(us) ((u64)(us) * timer_freq / SEC_TO_US)
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void pkvm_udelay(unsigned long usecs)
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{
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u64 ticks = pkvm_time_us_to_ticks(usecs);
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u64 start = pkvm_ticks_get();
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while (true) {
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u64 cur = pkvm_ticks_get();
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if ((cur - start) >= ticks || cur < start)
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break;
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/* TODO wfe */
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cpu_relax();
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}
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}
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