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Commit f61c94bb authored by Bharat Bhushan's avatar Bharat Bhushan Committed by Alexander Graf
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KVM: PPC: booke: Add watchdog emulation 



This patch adds the watchdog emulation in KVM. The watchdog
emulation is enabled by KVM_ENABLE_CAP(KVM_CAP_PPC_BOOKE_WATCHDOG) ioctl.
The kernel timer are used for watchdog emulation and emulates
h/w watchdog state machine. On watchdog timer expiry, it exit to QEMU
if TCR.WRC is non ZERO. QEMU can reset/shutdown etc depending upon how
it is configured.

Signed-off-by: default avatarLiu Yu <yu.liu@freescale.com>
Signed-off-by: default avatarScott Wood <scottwood@freescale.com>
[bharat.bhushan@freescale.com: reworked patch]
Signed-off-by: default avatarBharat Bhushan <bharat.bhushan@freescale.com>
[agraf: adjust to new request framework]
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
parent 7c973a2e

arch/powerpc/include/asm/kvm_host.h

+3 −0
Original line number Diff line number Diff line
@@ -471,6 +471,8 @@ struct kvm_vcpu_arch { 
	ulong fault_esr;

	ulong queued_dear;

	ulong queued_esr;

	spinlock_t wdt_lock;

	struct timer_list wdt_timer;

	u32 tlbcfg[4];

	u32 mmucfg;

	u32 epr;
@@ -486,6 +488,7 @@ struct kvm_vcpu_arch { 
	u8 osi_needed;

	u8 osi_enabled;

	u8 papr_enabled;

	u8 watchdog_enabled;

	u8 sane;

	u8 cpu_type;

	u8 hcall_needed;

arch/powerpc/include/asm/kvm_ppc.h

+2 −0
Original line number Diff line number Diff line
@@ -68,6 +68,8 @@ extern void kvmppc_emulate_dec(struct kvm_vcpu *vcpu); 
extern u32 kvmppc_get_dec(struct kvm_vcpu *vcpu, u64 tb);

extern void kvmppc_decrementer_func(unsigned long data);

extern int kvmppc_sanity_check(struct kvm_vcpu *vcpu);

extern int kvmppc_subarch_vcpu_init(struct kvm_vcpu *vcpu);

extern void kvmppc_subarch_vcpu_uninit(struct kvm_vcpu *vcpu);



/* Core-specific hooks */

arch/powerpc/include/asm/reg_booke.h

+7 −0
Original line number Diff line number Diff line
@@ -539,6 +539,13 @@ 
#define TCR_FIE		0x00800000	/* FIT Interrupt Enable */

#define TCR_ARE		0x00400000	/* Auto Reload Enable */



#ifdef CONFIG_E500

#define TCR_GET_WP(tcr)  ((((tcr) & 0xC0000000) >> 30) | \

			      (((tcr) & 0x1E0000) >> 15))

#else

#define TCR_GET_WP(tcr)  (((tcr) & 0xC0000000) >> 30)

#endif



/* Bit definitions for the TSR. */

#define TSR_ENW		0x80000000	/* Enable Next Watchdog */

#define TSR_WIS		0x40000000	/* WDT Interrupt Status */

arch/powerpc/kvm/book3s.c

+9 −0
Original line number Diff line number Diff line
@@ -411,6 +411,15 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu) 
	return 0;

}



int kvmppc_subarch_vcpu_init(struct kvm_vcpu *vcpu)

{

	return 0;

}



void kvmppc_subarch_vcpu_uninit(struct kvm_vcpu *vcpu)

{

}



int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)

{

	int i;

arch/powerpc/kvm/booke.c

+155 −0
Original line number Diff line number Diff line
@@ -209,6 +209,16 @@ void kvmppc_core_dequeue_external(struct kvm_vcpu *vcpu, 
	clear_bit(BOOKE_IRQPRIO_EXTERNAL_LEVEL, &vcpu->arch.pending_exceptions);

}



static void kvmppc_core_queue_watchdog(struct kvm_vcpu *vcpu)

{

	kvmppc_booke_queue_irqprio(vcpu, BOOKE_IRQPRIO_WATCHDOG);

}



static void kvmppc_core_dequeue_watchdog(struct kvm_vcpu *vcpu)

{

	clear_bit(BOOKE_IRQPRIO_WATCHDOG, &vcpu->arch.pending_exceptions);

}



static void set_guest_srr(struct kvm_vcpu *vcpu, unsigned long srr0, u32 srr1)

{

#ifdef CONFIG_KVM_BOOKE_HV
@@ -328,6 +338,7 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu *vcpu, 
		msr_mask = MSR_CE | MSR_ME | MSR_DE;

		int_class = INT_CLASS_NONCRIT;

		break;

	case BOOKE_IRQPRIO_WATCHDOG:

	case BOOKE_IRQPRIO_CRITICAL:

	case BOOKE_IRQPRIO_DBELL_CRIT:

		allowed = vcpu->arch.shared->msr & MSR_CE;
@@ -407,12 +418,121 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu *vcpu, 
	return allowed;

}



/*

 * Return the number of jiffies until the next timeout.  If the timeout is

 * longer than the NEXT_TIMER_MAX_DELTA, then return NEXT_TIMER_MAX_DELTA

 * because the larger value can break the timer APIs.

 */

static unsigned long watchdog_next_timeout(struct kvm_vcpu *vcpu)

{

	u64 tb, wdt_tb, wdt_ticks = 0;

	u64 nr_jiffies = 0;

	u32 period = TCR_GET_WP(vcpu->arch.tcr);



	wdt_tb = 1ULL << (63 - period);

	tb = get_tb();

	/*

	 * The watchdog timeout will hapeen when TB bit corresponding

	 * to watchdog will toggle from 0 to 1.

	 */

	if (tb & wdt_tb)

		wdt_ticks = wdt_tb;



	wdt_ticks += wdt_tb - (tb & (wdt_tb - 1));



	/* Convert timebase ticks to jiffies */

	nr_jiffies = wdt_ticks;



	if (do_div(nr_jiffies, tb_ticks_per_jiffy))

		nr_jiffies++;



	return min_t(unsigned long long, nr_jiffies, NEXT_TIMER_MAX_DELTA);

}



static void arm_next_watchdog(struct kvm_vcpu *vcpu)

{

	unsigned long nr_jiffies;

	unsigned long flags;



	/*

	 * If TSR_ENW and TSR_WIS are not set then no need to exit to

	 * userspace, so clear the KVM_REQ_WATCHDOG request.

	 */

	if ((vcpu->arch.tsr & (TSR_ENW | TSR_WIS)) != (TSR_ENW | TSR_WIS))

		clear_bit(KVM_REQ_WATCHDOG, &vcpu->requests);



	spin_lock_irqsave(&vcpu->arch.wdt_lock, flags);

	nr_jiffies = watchdog_next_timeout(vcpu);

	/*

	 * If the number of jiffies of watchdog timer >= NEXT_TIMER_MAX_DELTA

	 * then do not run the watchdog timer as this can break timer APIs.

	 */

	if (nr_jiffies < NEXT_TIMER_MAX_DELTA)

		mod_timer(&vcpu->arch.wdt_timer, jiffies + nr_jiffies);

	else

		del_timer(&vcpu->arch.wdt_timer);

	spin_unlock_irqrestore(&vcpu->arch.wdt_lock, flags);

}



void kvmppc_watchdog_func(unsigned long data)

{

	struct kvm_vcpu *vcpu = (struct kvm_vcpu *)data;

	u32 tsr, new_tsr;

	int final;



	do {

		new_tsr = tsr = vcpu->arch.tsr;

		final = 0;



		/* Time out event */

		if (tsr & TSR_ENW) {

			if (tsr & TSR_WIS)

				final = 1;

			else

				new_tsr = tsr | TSR_WIS;

		} else {

			new_tsr = tsr | TSR_ENW;

		}

	} while (cmpxchg(&vcpu->arch.tsr, tsr, new_tsr) != tsr);



	if (new_tsr & TSR_WIS) {

		smp_wmb();

		kvm_make_request(KVM_REQ_PENDING_TIMER, vcpu);

		kvm_vcpu_kick(vcpu);

	}



	/*

	 * If this is final watchdog expiry and some action is required

	 * then exit to userspace.

	 */

	if (final && (vcpu->arch.tcr & TCR_WRC_MASK) &&

	    vcpu->arch.watchdog_enabled) {

		smp_wmb();

		kvm_make_request(KVM_REQ_WATCHDOG, vcpu);

		kvm_vcpu_kick(vcpu);

	}



	/*

	 * Stop running the watchdog timer after final expiration to

	 * prevent the host from being flooded with timers if the

	 * guest sets a short period.

	 * Timers will resume when TSR/TCR is updated next time.

	 */

	if (!final)

		arm_next_watchdog(vcpu);

}



static void update_timer_ints(struct kvm_vcpu *vcpu)

{

	if ((vcpu->arch.tcr & TCR_DIE) && (vcpu->arch.tsr & TSR_DIS))

		kvmppc_core_queue_dec(vcpu);

	else

		kvmppc_core_dequeue_dec(vcpu);



	if ((vcpu->arch.tcr & TCR_WIE) && (vcpu->arch.tsr & TSR_WIS))

		kvmppc_core_queue_watchdog(vcpu);

	else

		kvmppc_core_dequeue_watchdog(vcpu);

}



static void kvmppc_core_check_exceptions(struct kvm_vcpu *vcpu)
@@ -466,6 +586,11 @@ int kvmppc_core_check_requests(struct kvm_vcpu *vcpu) 
		kvmppc_core_flush_tlb(vcpu);

#endif



	if (kvm_check_request(KVM_REQ_WATCHDOG, vcpu)) {

		vcpu->run->exit_reason = KVM_EXIT_WATCHDOG;

		r = 0;

	}



	return r;

}
@@ -995,6 +1120,21 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu) 
	return r;

}



int kvmppc_subarch_vcpu_init(struct kvm_vcpu *vcpu)

{

	/* setup watchdog timer once */

	spin_lock_init(&vcpu->arch.wdt_lock);

	setup_timer(&vcpu->arch.wdt_timer, kvmppc_watchdog_func,

		    (unsigned long)vcpu);



	return 0;

}



void kvmppc_subarch_vcpu_uninit(struct kvm_vcpu *vcpu)

{

	del_timer_sync(&vcpu->arch.wdt_timer);

}



int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)

{

	int i;
@@ -1090,7 +1230,13 @@ static int set_sregs_base(struct kvm_vcpu *vcpu, 
	}



	if (sregs->u.e.update_special & KVM_SREGS_E_UPDATE_TSR) {

		u32 old_tsr = vcpu->arch.tsr;



		vcpu->arch.tsr = sregs->u.e.tsr;



		if ((old_tsr ^ vcpu->arch.tsr) & (TSR_ENW | TSR_WIS))

			arm_next_watchdog(vcpu);



		update_timer_ints(vcpu);

	}
@@ -1251,6 +1397,7 @@ void kvmppc_core_commit_memory_region(struct kvm *kvm, 
void kvmppc_set_tcr(struct kvm_vcpu *vcpu, u32 new_tcr)

{

	vcpu->arch.tcr = new_tcr;

	arm_next_watchdog(vcpu);

	update_timer_ints(vcpu);

}
@@ -1265,6 +1412,14 @@ void kvmppc_set_tsr_bits(struct kvm_vcpu *vcpu, u32 tsr_bits) 
void kvmppc_clr_tsr_bits(struct kvm_vcpu *vcpu, u32 tsr_bits)

{

	clear_bits(tsr_bits, &vcpu->arch.tsr);



	/*

	 * We may have stopped the watchdog due to

	 * being stuck on final expiration.

	 */

	if (tsr_bits & (TSR_ENW | TSR_WIS))

		arm_next_watchdog(vcpu);



	update_timer_ints(vcpu);

}