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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-18 18:50:36 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-18 18:50:36 +0000 |
commit | 50ba0232fd5312410f1b65247e774244f89a628e (patch) | |
tree | fd8f2fc78e9e548af0ff9590276602ee6125be00 /arch/loongarch/kvm/timer.c | |
parent | Releasing progress-linux version 6.7.12-1~progress7.99u1. (diff) | |
download | linux-50ba0232fd5312410f1b65247e774244f89a628e.tar.xz linux-50ba0232fd5312410f1b65247e774244f89a628e.zip |
Merging upstream version 6.8.9.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/loongarch/kvm/timer.c')
-rw-r--r-- | arch/loongarch/kvm/timer.c | 129 |
1 files changed, 76 insertions, 53 deletions
diff --git a/arch/loongarch/kvm/timer.c b/arch/loongarch/kvm/timer.c index 284bf553fe..111328f608 100644 --- a/arch/loongarch/kvm/timer.c +++ b/arch/loongarch/kvm/timer.c @@ -65,40 +65,23 @@ void kvm_init_timer(struct kvm_vcpu *vcpu, unsigned long timer_hz) } /* - * Restore hard timer state and enable guest to access timer registers - * without trap, should be called with irq disabled - */ -void kvm_acquire_timer(struct kvm_vcpu *vcpu) -{ - unsigned long cfg; - - cfg = read_csr_gcfg(); - if (!(cfg & CSR_GCFG_TIT)) - return; - - /* Enable guest access to hard timer */ - write_csr_gcfg(cfg & ~CSR_GCFG_TIT); - - /* - * Freeze the soft-timer and sync the guest stable timer with it. We do - * this with interrupts disabled to avoid latency. - */ - hrtimer_cancel(&vcpu->arch.swtimer); -} - -/* * Restore soft timer state from saved context. */ void kvm_restore_timer(struct kvm_vcpu *vcpu) { - unsigned long cfg, delta, period; + unsigned long cfg, estat; + unsigned long ticks, delta, period; ktime_t expire, now; struct loongarch_csrs *csr = vcpu->arch.csr; /* * Set guest stable timer cfg csr + * Disable timer before restore estat CSR register, avoid to + * get invalid timer interrupt for old timer cfg */ cfg = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_TCFG); + + write_gcsr_timercfg(0); kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_ESTAT); kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_TCFG); if (!(cfg & CSR_TCFG_EN)) { @@ -108,23 +91,55 @@ void kvm_restore_timer(struct kvm_vcpu *vcpu) } /* + * Freeze the soft-timer and sync the guest stable timer with it. + */ + hrtimer_cancel(&vcpu->arch.swtimer); + + /* + * From LoongArch Reference Manual Volume 1 Chapter 7.6.2 + * If oneshot timer is fired, CSR TVAL will be -1, there are two + * conditions: + * 1) timer is fired during exiting to host + * 2) timer is fired and vm is doing timer irq, and then exiting to + * host. Host should not inject timer irq to avoid spurious + * timer interrupt again + */ + ticks = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_TVAL); + estat = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_ESTAT); + if (!(cfg & CSR_TCFG_PERIOD) && (ticks > cfg)) { + /* + * Writing 0 to LOONGARCH_CSR_TVAL will inject timer irq + * and set CSR TVAL with -1 + */ + write_gcsr_timertick(0); + + /* + * Writing CSR_TINTCLR_TI to LOONGARCH_CSR_TINTCLR will clear + * timer interrupt, and CSR TVAL keeps unchanged with -1, it + * avoids spurious timer interrupt + */ + if (!(estat & CPU_TIMER)) + gcsr_write(CSR_TINTCLR_TI, LOONGARCH_CSR_TINTCLR); + return; + } + + /* * Set remainder tick value if not expired */ + delta = 0; now = ktime_get(); expire = vcpu->arch.expire; if (ktime_before(now, expire)) delta = ktime_to_tick(vcpu, ktime_sub(expire, now)); - else { - if (cfg & CSR_TCFG_PERIOD) { - period = cfg & CSR_TCFG_VAL; - delta = ktime_to_tick(vcpu, ktime_sub(now, expire)); - delta = period - (delta % period); - } else - delta = 0; + else if (cfg & CSR_TCFG_PERIOD) { + period = cfg & CSR_TCFG_VAL; + delta = ktime_to_tick(vcpu, ktime_sub(now, expire)); + delta = period - (delta % period); + /* * Inject timer here though sw timer should inject timer * interrupt async already, since sw timer may be cancelled - * during injecting intr async in function kvm_acquire_timer + * during injecting intr async */ kvm_queue_irq(vcpu, INT_TI); } @@ -139,27 +154,41 @@ void kvm_restore_timer(struct kvm_vcpu *vcpu) */ static void _kvm_save_timer(struct kvm_vcpu *vcpu) { - unsigned long ticks, delta; + unsigned long ticks, delta, cfg; ktime_t expire; struct loongarch_csrs *csr = vcpu->arch.csr; + cfg = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_TCFG); ticks = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_TVAL); - delta = tick_to_ns(vcpu, ticks); - expire = ktime_add_ns(ktime_get(), delta); - vcpu->arch.expire = expire; - if (ticks) { + + /* + * From LoongArch Reference Manual Volume 1 Chapter 7.6.2 + * If period timer is fired, CSR TVAL will be reloaded from CSR TCFG + * If oneshot timer is fired, CSR TVAL will be -1 + * Here judge one-shot timer fired by checking whether TVAL is larger + * than TCFG + */ + if (ticks < cfg) { + delta = tick_to_ns(vcpu, ticks); + expire = ktime_add_ns(ktime_get(), delta); + vcpu->arch.expire = expire; + /* - * Update hrtimer to use new timeout * HRTIMER_MODE_PINNED is suggested since vcpu may run in * the same physical cpu in next time */ - hrtimer_cancel(&vcpu->arch.swtimer); hrtimer_start(&vcpu->arch.swtimer, expire, HRTIMER_MODE_ABS_PINNED); - } else + } else if (vcpu->stat.generic.blocking) { /* - * Inject timer interrupt so that hall polling can dectect and exit + * Inject timer interrupt so that halt polling can dectect and exit. + * VCPU is scheduled out already and sleeps in rcuwait queue and + * will not poll pending events again. kvm_queue_irq() is not enough, + * hrtimer swtimer should be used here. */ - kvm_queue_irq(vcpu, INT_TI); + expire = ktime_add_ns(ktime_get(), 10); + vcpu->arch.expire = expire; + hrtimer_start(&vcpu->arch.swtimer, expire, HRTIMER_MODE_ABS_PINNED); + } } /* @@ -168,21 +197,15 @@ static void _kvm_save_timer(struct kvm_vcpu *vcpu) */ void kvm_save_timer(struct kvm_vcpu *vcpu) { - unsigned long cfg; struct loongarch_csrs *csr = vcpu->arch.csr; preempt_disable(); - cfg = read_csr_gcfg(); - if (!(cfg & CSR_GCFG_TIT)) { - /* Disable guest use of hard timer */ - write_csr_gcfg(cfg | CSR_GCFG_TIT); - - /* Save hard timer state */ - kvm_save_hw_gcsr(csr, LOONGARCH_CSR_TCFG); - kvm_save_hw_gcsr(csr, LOONGARCH_CSR_TVAL); - if (kvm_read_sw_gcsr(csr, LOONGARCH_CSR_TCFG) & CSR_TCFG_EN) - _kvm_save_timer(vcpu); - } + + /* Save hard timer state */ + kvm_save_hw_gcsr(csr, LOONGARCH_CSR_TCFG); + kvm_save_hw_gcsr(csr, LOONGARCH_CSR_TVAL); + if (kvm_read_sw_gcsr(csr, LOONGARCH_CSR_TCFG) & CSR_TCFG_EN) + _kvm_save_timer(vcpu); /* Save timer-related state to vCPU context */ kvm_save_hw_gcsr(csr, LOONGARCH_CSR_ESTAT); |