Adding upstream version 6.7.7.upstream/6.7.7

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 197 insertions, 0 deletions

diff --git a/arch/loongarch/kvm/timer.c b/arch/loongarch/kvm/timer.c
new file mode 100644
index 0000000000..284bf553fe
--- /dev/null
+++ b/arch/loongarch/kvm/timer.c
@@ -0,0 +1,197 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020-2023 Loongson Technology Corporation Limited
+ */
+
+#include <linux/kvm_host.h>
+#include <asm/kvm_csr.h>
+#include <asm/kvm_vcpu.h>
+
+/*
+ * ktime_to_tick() - Scale ktime_t to timer tick value.
+ */
+static inline u64 ktime_to_tick(struct kvm_vcpu *vcpu, ktime_t now)
+{
+	u64 delta;
+
+	delta = ktime_to_ns(now);
+	return div_u64(delta * vcpu->arch.timer_mhz, MNSEC_PER_SEC);
+}
+
+static inline u64 tick_to_ns(struct kvm_vcpu *vcpu, u64 tick)
+{
+	return div_u64(tick * MNSEC_PER_SEC, vcpu->arch.timer_mhz);
+}
+
+/*
+ * Push timer forward on timeout.
+ * Handle an hrtimer event by push the hrtimer forward a period.
+ */
+static enum hrtimer_restart kvm_count_timeout(struct kvm_vcpu *vcpu)
+{
+	unsigned long cfg, period;
+
+	/* Add periodic tick to current expire time */
+	cfg = kvm_read_sw_gcsr(vcpu->arch.csr, LOONGARCH_CSR_TCFG);
+	if (cfg & CSR_TCFG_PERIOD) {
+		period = tick_to_ns(vcpu, cfg & CSR_TCFG_VAL);
+		hrtimer_add_expires_ns(&vcpu->arch.swtimer, period);
+		return HRTIMER_RESTART;
+	} else
+		return HRTIMER_NORESTART;
+}
+
+/* Low level hrtimer wake routine */
+enum hrtimer_restart kvm_swtimer_wakeup(struct hrtimer *timer)
+{
+	struct kvm_vcpu *vcpu;
+
+	vcpu = container_of(timer, struct kvm_vcpu, arch.swtimer);
+	kvm_queue_irq(vcpu, INT_TI);
+	rcuwait_wake_up(&vcpu->wait);
+
+	return kvm_count_timeout(vcpu);
+}
+
+/*
+ * Initialise the timer to the specified frequency, zero it
+ */
+void kvm_init_timer(struct kvm_vcpu *vcpu, unsigned long timer_hz)
+{
+	vcpu->arch.timer_mhz = timer_hz >> 20;
+
+	/* Starting at 0 */
+	kvm_write_sw_gcsr(vcpu->arch.csr, LOONGARCH_CSR_TVAL, 0);
+}
+
+/*
+ * 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;
+	ktime_t expire, now;
+	struct loongarch_csrs *csr = vcpu->arch.csr;
+
+	/*
+	 * Set guest stable timer cfg csr
+	 */
+	cfg = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_TCFG);
+	kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_ESTAT);
+	kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_TCFG);
+	if (!(cfg & CSR_TCFG_EN)) {
+		/* Guest timer is disabled, just restore timer registers */
+		kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_TVAL);
+		return;
+	}
+
+	/*
+	 * Set remainder tick value if not expired
+	 */
+	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;
+		/*
+		 * 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
+		 */
+		kvm_queue_irq(vcpu, INT_TI);
+	}
+
+	write_gcsr_timertick(delta);
+}
+
+/*
+ * Save guest timer state and switch to software emulation of guest
+ * timer. The hard timer must already be in use, so preemption should be
+ * disabled.
+ */
+static void _kvm_save_timer(struct kvm_vcpu *vcpu)
+{
+	unsigned long ticks, delta;
+	ktime_t expire;
+	struct loongarch_csrs *csr = vcpu->arch.csr;
+
+	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) {
+		/*
+		 * 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
+		/*
+		 * Inject timer interrupt so that hall polling can dectect and exit
+		 */
+		kvm_queue_irq(vcpu, INT_TI);
+}
+
+/*
+ * Save guest timer state and switch to soft guest timer if hard timer was in
+ * use.
+ */
+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 timer-related state to vCPU context */
+	kvm_save_hw_gcsr(csr, LOONGARCH_CSR_ESTAT);
+	preempt_enable();
+}
+
+void kvm_reset_timer(struct kvm_vcpu *vcpu)
+{
+	write_gcsr_timercfg(0);
+	kvm_write_sw_gcsr(vcpu->arch.csr, LOONGARCH_CSR_TCFG, 0);
+	hrtimer_cancel(&vcpu->arch.swtimer);
+}