This patch adds the watchdog emulation in KVM. The watchdog
emulation is enabled by KVM_ENABLE_CAP(KVM_CAP_PPC_WDT) 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: Liu Yu <yu.liu@xxxxxxxxxxxxx>
Signed-off-by: Scott Wood <scottwood@xxxxxxxxxxxxx>
Signed-off-by: Bharat Bhushan <bharat.bhushan@xxxxxxxxxxxxx>
---
arch/powerpc/include/asm/kvm_host.h | 2 +
arch/powerpc/include/asm/kvm_ppc.h | 3 +
arch/powerpc/include/asm/reg_booke.h | 2 +
arch/powerpc/kvm/44x.c | 1 +
arch/powerpc/kvm/booke.c | 125 ++++++++++++++++++++++++++++++++++
arch/powerpc/kvm/booke_emulate.c | 6 ++-
arch/powerpc/kvm/powerpc.c | 25 ++++++-
include/linux/kvm.h | 2 +
8 files changed, 162 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 50ea12f..a9e5aed 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -467,6 +467,7 @@ struct kvm_vcpu_arch {
ulong fault_esr;
ulong queued_dear;
ulong queued_esr;
+ struct timer_list wdt_timer;
u32 tlbcfg[4];
u32 mmucfg;
u32 epr;
@@ -482,6 +483,7 @@ struct kvm_vcpu_arch {
u8 osi_needed;
u8 osi_enabled;
u8 papr_enabled;
+ u8 watchdog_enable;
u8 sane;
u8 cpu_type;
u8 hcall_needed;
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index 0124937..e5cf4b9 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -67,6 +67,7 @@ extern int kvmppc_emulate_mmio(struct kvm_run *run, struct kvm_vcpu *vcpu);
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 void kvmppc_watchdog_func(unsigned long data);
extern int kvmppc_sanity_check(struct kvm_vcpu *vcpu);
/* Core-specific hooks */
@@ -104,6 +105,8 @@ extern void kvmppc_core_queue_external(struct kvm_vcpu *vcpu,
struct kvm_interrupt *irq);
extern void kvmppc_core_dequeue_external(struct kvm_vcpu *vcpu,
struct kvm_interrupt *irq);
+extern void kvmppc_core_queue_watchdog(struct kvm_vcpu *vcpu);
+extern void kvmppc_core_dequeue_watchdog(struct kvm_vcpu *vcpu);
extern int kvmppc_core_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
unsigned int op, int *advance);
diff --git a/arch/powerpc/include/asm/reg_booke.h b/arch/powerpc/include/asm/reg_booke.h
index 2d916c4..7efb3f5 100644
--- a/arch/powerpc/include/asm/reg_booke.h
+++ b/arch/powerpc/include/asm/reg_booke.h
@@ -538,6 +538,8 @@
#define FP_2_21 3 /* 2^21 clocks */
#define TCR_FIE 0x00800000 /* FIT Interrupt Enable */
#define TCR_ARE 0x00400000 /* Auto Reload Enable */
+#define TCR_GET_FSL_WP(tcr) ((((tcr) & 0xC0000000) >> 30) | \
+ (((tcr) & 0x1E0000) >> 15))
/* Bit definitions for the TSR. */
#define TSR_ENW 0x80000000 /* Enable Next Watchdog */
diff --git a/arch/powerpc/kvm/44x.c b/arch/powerpc/kvm/44x.c
index 50e7dbc..a213aba 100644
--- a/arch/powerpc/kvm/44x.c
+++ b/arch/powerpc/kvm/44x.c
@@ -28,6 +28,7 @@
#include <asm/kvm_44x.h>
#include <asm/kvm_ppc.h>
+#include "booke.h"
#include "44x_tlb.h"
#include "booke.h"
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index d25a097..ad30f75 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -206,6 +206,16 @@ void kvmppc_core_dequeue_external(struct kvm_vcpu *vcpu,
clear_bit(BOOKE_IRQPRIO_EXTERNAL_LEVEL, &vcpu->arch.pending_exceptions);
}
+void kvmppc_core_queue_watchdog(struct kvm_vcpu *vcpu)
+{
+ kvmppc_booke_queue_irqprio(vcpu, BOOKE_IRQPRIO_WATCHDOG);
+}
+
+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
@@ -325,6 +335,7 @@ 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;
@@ -404,12 +415,98 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu *vcpu,
return allowed;
}
+/*
+ * The timer system can almost deal with LONG_MAX timeouts, except that
+ * when you get very close to LONG_MAX, the slack added can cause overflow.
+ *
+ * LONG_MAX/2 is a conservative threshold, but it should be adequate for
+ * any realistic use.
+ */
+#define MAX_TIMEOUT (LONG_MAX/2)
+
+/*
+ * Return the number of jiffies until the next timeout. If the timeout is
+ * longer than the MAX_TIMEOUT, that we return MAX_TIMEOUT instead.
+ */
+static unsigned long watchdog_next_timeout(struct kvm_vcpu *vcpu)
+{
+ unsigned long long tb, mask, nr_jiffies = 0;
+ u32 period = TCR_GET_FSL_WP(vcpu->arch.tcr);
+
+ mask = 1ULL << (63 - period);
+ tb = get_tb();
+ if (tb & mask)
+ nr_jiffies += mask;
+
+ nr_jiffies += mask - (tb & (mask - 1));
+
+ if (do_div(nr_jiffies, tb_ticks_per_jiffy))
+ nr_jiffies++;
+
+ return min_t(unsigned long long, nr_jiffies, MAX_TIMEOUT);
+}
+
+static void arm_next_watchdog(struct kvm_vcpu *vcpu)
+{
+ unsigned long nr_jiffies;
+
+ nr_jiffies = watchdog_next_timeout(vcpu);
+ if (nr_jiffies < MAX_TIMEOUT)
+ mod_timer(&vcpu->arch.wdt_timer, jiffies + nr_jiffies);
+ else
+ del_timer(&vcpu->arch.wdt_timer);
+}
+
+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) {
+ new_tsr = (tsr & ~TCR_WRC_MASK) |
+ (vcpu->arch.tcr & TCR_WRC_MASK);
+ vcpu->arch.tcr &= ~TCR_WRC_MASK;
+ 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 | TCR_WRC_MASK)) {
+ smp_wmb();
+ kvm_make_request(KVM_REQ_PENDING_TIMER, vcpu);
+ kvm_vcpu_kick(vcpu);
+ }
+
+ /*
+ * Avoid getting a storm of timers if the guest sets
+ * the period very short. We'll restart it if anything
+ * changes.
+ */
+ 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)
@@ -516,6 +613,12 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
goto out;
}
+ if (vcpu->arch.tsr & TCR_WRC_MASK) {
+ kvm_run->exit_reason = KVM_EXIT_WDT;
+ ret = 0;
+ goto out;
+ }
+
kvm_guest_enter();
#ifdef CONFIG_PPC_FPU
@@ -977,6 +1080,10 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
kvmppc_account_exit(vcpu, SIGNAL_EXITS);
}
}
+ if (vcpu->arch.tsr & TCR_WRC_MASK) {
+ run->exit_reason = KVM_EXIT_WDT;
+ r = RESUME_HOST | (r & RESUME_FLAG_NV);
+ }
return r;
}
@@ -1106,7 +1213,14 @@ 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 | TCR_WRC_MASK))
+ arm_next_watchdog(vcpu);
+
update_timer_ints(vcpu);
}
@@ -1267,6 +1381,8 @@ 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;
+ if (vcpu->arch.watchdog_enable)
+ arm_next_watchdog(vcpu);
update_timer_ints(vcpu);
}
@@ -1281,6 +1397,15 @@ 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 (vcpu->arch.watchdog_enable && (tsr_bits & (TSR_ENW |
+ TSR_WIS | TCR_WRC_MASK)))
+ arm_next_watchdog(vcpu);
+
update_timer_ints(vcpu);
}
diff --git a/arch/powerpc/kvm/booke_emulate.c b/arch/powerpc/kvm/booke_emulate.c
index 12834bb..cc94d42 100644
--- a/arch/powerpc/kvm/booke_emulate.c
+++ b/arch/powerpc/kvm/booke_emulate.c
@@ -145,7 +145,11 @@ int kvmppc_booke_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, ulong spr_val)
kvmppc_clr_tsr_bits(vcpu, spr_val);
break;
case SPRN_TCR:
- kvmppc_set_tcr(vcpu, spr_val);
+ /* WRC can only be programmed when WRC=0 */
+ if (TCR_WRC_MASK & vcpu->arch.tcr)
+ spr_val &= ~TCR_WRC_MASK;
+ kvmppc_set_tcr(vcpu,
+ spr_val | (TCR_WRC_MASK & vcpu->arch.tcr));
break;
case SPRN_DECAR:
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 87f4dc8..35a1ff3 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -38,9 +38,15 @@
int kvm_arch_vcpu_runnable(struct kvm_vcpu *v)
{
- return !(v->arch.shared->msr & MSR_WE) ||
- !!(v->arch.pending_exceptions) ||
- v->requests;
+ bool ret = !(v->arch.shared->msr & MSR_WE) ||
+ !!(v->arch.pending_exceptions) ||
+ v->requests;
+
+#ifdef CONFIG_BOOKE
+ ret = ret || (v->arch.tsr & TCR_WRC_MASK);
+#endif
+
+ return ret;
}
int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
@@ -237,6 +243,7 @@ int kvm_dev_ioctl_check_extension(long ext)
case KVM_CAP_PPC_GET_PVINFO:
#if defined(CONFIG_KVM_E500V2) || defined(CONFIG_KVM_E500MC)
case KVM_CAP_SW_TLB:
+ case KVM_CAP_PPC_WDT:
#endif
r = 1;
break;
@@ -393,6 +400,10 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu)
{
kvmppc_mmu_destroy(vcpu);
+#ifdef CONFIG_BOOKE
+ if (vcpu->arch.watchdog_enable)
+ del_timer(&vcpu->arch.wdt_timer);
+#endif
}
void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
@@ -637,6 +648,14 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
r = 0;
vcpu->arch.papr_enabled = true;
break;
+#ifdef CONFIG_BOOKE
+ case KVM_CAP_PPC_WDT:
+ r = 0;
+ vcpu->arch.watchdog_enable = true;
+ setup_timer(&vcpu->arch.wdt_timer, kvmppc_watchdog_func,
+ (unsigned long)vcpu);
+ break;
+#endif
#if defined(CONFIG_KVM_E500V2) || defined(CONFIG_KVM_E500MC)
case KVM_CAP_SW_TLB: {
struct kvm_config_tlb cfg;
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 2ce09aa..b9fdb52 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -163,6 +163,7 @@ struct kvm_pit_config {
#define KVM_EXIT_OSI 18
#define KVM_EXIT_PAPR_HCALL 19
#define KVM_EXIT_S390_UCONTROL 20
+#define KVM_EXIT_WDT 21
/* For KVM_EXIT_INTERNAL_ERROR */
#define KVM_INTERNAL_ERROR_EMULATION 1
@@ -618,6 +619,7 @@ struct kvm_ppc_smmu_info {
#define KVM_CAP_PPC_GET_SMMU_INFO 78
#define KVM_CAP_S390_COW 79
#define KVM_CAP_PPC_ALLOC_HTAB 80
+#define KVM_CAP_PPC_WDT 81
#ifdef KVM_CAP_IRQ_ROUTING
--
1.7.0.4
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