forked from Minki/linux
d9e1397783
If you're running with a userspace gic or other interrupt controller (that is no vgic in the kernel), then you have so far not been able to use the architected timers, because the output of the architected timers, which are driven inside the kernel, was a kernel-only construct between the arch timer code and the vgic. This patch implements the new KVM_CAP_ARM_USER_IRQ feature, where we use a side channel on the kvm_run structure, run->s.regs.device_irq_level, to always notify userspace of the timer output levels when using a userspace irqchip. This works by ensuring that before we enter the guest, if the timer output level has changed compared to what we last told userspace, we don't enter the guest, but instead return to userspace to notify it of the new level. If we are exiting, because of an MMIO for example, and the level changed at the same time, the value is also updated and userspace can sample the line as it needs. This is nicely achieved simply always updating the timer_irq_level field after the main run loop. Note that the kvm_timer_update_irq trace event is changed to show the host IRQ number for the timer instead of the guest IRQ number, because the kernel no longer know which IRQ userspace wires up the timer signal to. Also note that this patch implements all required functionality but does not yet advertise the capability. Reviewed-by: Alexander Graf <agraf@suse.de> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
86 lines
2.5 KiB
C
86 lines
2.5 KiB
C
/*
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* Copyright (C) 2012 ARM Ltd.
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* Author: Marc Zyngier <marc.zyngier@arm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef __ASM_ARM_KVM_ARCH_TIMER_H
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#define __ASM_ARM_KVM_ARCH_TIMER_H
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#include <linux/clocksource.h>
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#include <linux/hrtimer.h>
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#include <linux/workqueue.h>
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struct arch_timer_context {
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/* Registers: control register, timer value */
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u32 cnt_ctl;
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u64 cnt_cval;
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/* Timer IRQ */
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struct kvm_irq_level irq;
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/* Active IRQ state caching */
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bool active_cleared_last;
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/* Virtual offset */
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u64 cntvoff;
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};
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struct arch_timer_cpu {
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struct arch_timer_context vtimer;
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struct arch_timer_context ptimer;
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/* Background timer used when the guest is not running */
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struct hrtimer timer;
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/* Work queued with the above timer expires */
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struct work_struct expired;
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/* Background timer active */
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bool armed;
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/* Is the timer enabled */
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bool enabled;
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};
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int kvm_timer_hyp_init(void);
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int kvm_timer_enable(struct kvm_vcpu *vcpu);
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int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu,
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const struct kvm_irq_level *virt_irq,
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const struct kvm_irq_level *phys_irq);
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void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu);
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void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu);
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void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu);
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bool kvm_timer_should_notify_user(struct kvm_vcpu *vcpu);
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void kvm_timer_update_run(struct kvm_vcpu *vcpu);
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void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu);
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u64 kvm_arm_timer_get_reg(struct kvm_vcpu *, u64 regid);
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int kvm_arm_timer_set_reg(struct kvm_vcpu *, u64 regid, u64 value);
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bool kvm_timer_should_fire(struct arch_timer_context *timer_ctx);
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void kvm_timer_schedule(struct kvm_vcpu *vcpu);
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void kvm_timer_unschedule(struct kvm_vcpu *vcpu);
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u64 kvm_phys_timer_read(void);
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void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu);
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void kvm_timer_init_vhe(void);
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#define vcpu_vtimer(v) (&(v)->arch.timer_cpu.vtimer)
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#define vcpu_ptimer(v) (&(v)->arch.timer_cpu.ptimer)
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#endif
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