Having the timer IRQs duplicated into each vcpu isn't great, and
becomes absolutely awful with NV. So let's move these into
the per-VM arch_timer_vm_data structure.
This simplifies a lot of code, but requires us to introduce a
mutex so that we can reason about userspace trying to change
an interrupt number while another vcpu is running, something
that wasn't really well handled so far.
Reviewed-by: Colton Lewis <coltonlewis@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_host.h | 2 +
arch/arm64/kvm/arch_timer.c | 104 +++++++++++++++++-------------
arch/arm64/kvm/arm.c | 2 +
include/kvm/arm_arch_timer.h | 18 ++++--
4 files changed, 78 insertions(+), 48 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 116233a390e9..1280154c9ef3 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -223,6 +223,8 @@ struct kvm_arch {
#define KVM_ARCH_FLAG_SYSTEM_SUSPEND_ENABLED 5
/* VM counter offset */
#define KVM_ARCH_FLAG_VM_COUNTER_OFFSET 6
+ /* Timer PPIs made immutable */
+#define KVM_ARCH_FLAG_TIMER_PPIS_IMMUTABLE 7
unsigned long flags;
diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index 7cd0b0947454..88a38d45d352 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -851,7 +851,6 @@ static void timer_context_init(struct kvm_vcpu *vcpu, int timerid)
hrtimer_init(&ctxt->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
ctxt->hrtimer.function = kvm_hrtimer_expire;
- timer_irq(ctxt) = default_ppi[timerid];
switch (timerid) {
case TIMER_PTIMER:
@@ -880,6 +879,13 @@ void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
timer->bg_timer.function = kvm_bg_timer_expire;
}
+void kvm_timer_init_vm(struct kvm *kvm)
+{
+ mutex_init(&kvm->arch.timer_data.lock);
+ for (int i = 0; i < NR_KVM_TIMERS; i++)
+ kvm->arch.timer_data.ppi[i] = default_ppi[i];
+}
+
void kvm_timer_cpu_up(void)
{
enable_percpu_irq(host_vtimer_irq, host_vtimer_irq_flags);
@@ -1292,44 +1298,52 @@ void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu)
static bool timer_irqs_are_valid(struct kvm_vcpu *vcpu)
{
- int vtimer_irq, ptimer_irq, ret;
- unsigned long i;
+ u32 ppis = 0;
- vtimer_irq = timer_irq(vcpu_vtimer(vcpu));
- ret = kvm_vgic_set_owner(vcpu, vtimer_irq, vcpu_vtimer(vcpu));
- if (ret)
- return false;
+ mutex_lock(&vcpu->kvm->arch.timer_data.lock);
- ptimer_irq = timer_irq(vcpu_ptimer(vcpu));
- ret = kvm_vgic_set_owner(vcpu, ptimer_irq, vcpu_ptimer(vcpu));
- if (ret)
- return false;
+ for (int i = 0; i < NR_KVM_TIMERS; i++) {
+ struct arch_timer_context *ctx;
+ int irq;
- kvm_for_each_vcpu(i, vcpu, vcpu->kvm) {
- if (timer_irq(vcpu_vtimer(vcpu)) != vtimer_irq ||
- timer_irq(vcpu_ptimer(vcpu)) != ptimer_irq)
- return false;
+ ctx = vcpu_get_timer(vcpu, i);
+ irq = timer_irq(ctx);
+ if (kvm_vgic_set_owner(vcpu, irq, ctx))
+ break;
+
+ /*
+ * We know by construction that we only have PPIs, so
+ * all values are less than 32.
+ */
+ ppis |= BIT(irq);
}
- return true;
+ set_bit(KVM_ARCH_FLAG_TIMER_PPIS_IMMUTABLE, &vcpu->kvm->arch.flags);
+
+ mutex_unlock(&vcpu->kvm->arch.timer_data.lock);
+
+ return hweight32(ppis) == NR_KVM_TIMERS;
}
bool kvm_arch_timer_get_input_level(int vintid)
{
struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
- struct arch_timer_context *timer;
if (WARN(!vcpu, "No vcpu context!\n"))
return false;
- if (vintid == timer_irq(vcpu_vtimer(vcpu)))
- timer = vcpu_vtimer(vcpu);
- else if (vintid == timer_irq(vcpu_ptimer(vcpu)))
- timer = vcpu_ptimer(vcpu);
- else
- BUG();
+ for (int i = 0; i < NR_KVM_TIMERS; i++) {
+ struct arch_timer_context *ctx;
+
+ ctx = vcpu_get_timer(vcpu, i);
+ if (timer_irq(ctx) == vintid)
+ return kvm_timer_should_fire(ctx);
+ }
- return kvm_timer_should_fire(timer);
+ /* A timer IRQ has fired, but no matching timer was found? */
+ WARN_RATELIMIT(1, "timer INTID%d unknown\n", vintid);
+
+ return false;
}
int kvm_timer_enable(struct kvm_vcpu *vcpu)
@@ -1385,23 +1399,10 @@ void kvm_timer_init_vhe(void)
sysreg_clear_set(cntkctl_el1, 0, CNTHCTL_ECV);
}
-static void set_timer_irqs(struct kvm *kvm, int vtimer_irq, int ptimer_irq)
-{
- struct kvm_vcpu *vcpu;
- unsigned long i;
-
- kvm_for_each_vcpu(i, vcpu, kvm) {
- timer_irq(vcpu_vtimer(vcpu)) = vtimer_irq;
- timer_irq(vcpu_ptimer(vcpu)) = ptimer_irq;
- }
-}
-
int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
int __user *uaddr = (int __user *)(long)attr->addr;
- struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
- struct arch_timer_context *ptimer = vcpu_ptimer(vcpu);
- int irq;
+ int irq, idx, ret = 0;
if (!irqchip_in_kernel(vcpu->kvm))
return -EINVAL;
@@ -1412,21 +1413,36 @@ int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
if (!(irq_is_ppi(irq)))
return -EINVAL;
- if (vcpu->arch.timer_cpu.enabled)
- return -EBUSY;
+ mutex_lock(&vcpu->kvm->arch.timer_data.lock);
+
+ if (test_bit(KVM_ARCH_FLAG_TIMER_PPIS_IMMUTABLE,
+ &vcpu->kvm->arch.flags)) {
+ ret = -EBUSY;
+ goto out;
+ }
switch (attr->attr) {
case KVM_ARM_VCPU_TIMER_IRQ_VTIMER:
- set_timer_irqs(vcpu->kvm, irq, timer_irq(ptimer));
+ idx = TIMER_VTIMER;
break;
case KVM_ARM_VCPU_TIMER_IRQ_PTIMER:
- set_timer_irqs(vcpu->kvm, timer_irq(vtimer), irq);
+ idx = TIMER_PTIMER;
break;
default:
- return -ENXIO;
+ ret = -ENXIO;
+ goto out;
}
- return 0;
+ /*
+ * We cannot validate the IRQ unicity before we run, so take it at
+ * face value. The verdict will be given on first vcpu run, for each
+ * vcpu. Yes this is late. Blame it on the stupid API.
+ */
+ vcpu->kvm->arch.timer_data.ppi[idx] = irq;
+
+out:
+ mutex_unlock(&vcpu->kvm->arch.timer_data.lock);
+ return ret;
}
int kvm_arm_timer_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 1c8a4bbae684..4c5e9dfbf83a 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -148,6 +148,8 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
kvm_vgic_early_init(kvm);
+ kvm_timer_init_vm(kvm);
+
/* The maximum number of VCPUs is limited by the host's GIC model */
kvm->max_vcpus = kvm_arm_default_max_vcpus();
diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index 27cada09f588..f093ea9f540d 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -36,14 +36,16 @@ struct arch_timer_vm_data {
u64 voffset;
/* Offset applied to the physical timer/counter */
u64 poffset;
+
+ struct mutex lock;
+
+ /* The PPI for each timer, global to the VM */
+ u8 ppi[NR_KVM_TIMERS];
};
struct arch_timer_context {
struct kvm_vcpu *vcpu;
- /* Timer IRQ */
- struct kvm_irq_level irq;
-
/* Emulated Timer (may be unused) */
struct hrtimer hrtimer;
u64 ns_frac;
@@ -57,6 +59,11 @@ struct arch_timer_context {
*/
bool loaded;
+ /* Output level of the timer IRQ */
+ struct {
+ bool level;
+ } irq;
+
/* Duplicated state from arch_timer.c for convenience */
u32 host_timer_irq;
};
@@ -86,6 +93,8 @@ bool kvm_timer_should_notify_user(struct kvm_vcpu *vcpu);
void kvm_timer_update_run(struct kvm_vcpu *vcpu);
void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu);
+void kvm_timer_init_vm(struct kvm *kvm);
+
u64 kvm_arm_timer_get_reg(struct kvm_vcpu *, u64 regid);
int kvm_arm_timer_set_reg(struct kvm_vcpu *, u64 regid, u64 value);
@@ -109,7 +118,8 @@ bool kvm_arch_timer_get_input_level(int vintid);
#define arch_timer_ctx_index(ctx) ((ctx) - vcpu_timer((ctx)->vcpu)->timers)
-#define timer_irq(ctx) ((ctx)->irq.irq)
+#define timer_vm_data(ctx) (&(ctx)->vcpu->kvm->arch.timer_data)
+#define timer_irq(ctx) (timer_vm_data(ctx)->ppi[arch_timer_ctx_index(ctx)])
u64 kvm_arm_timer_read_sysreg(struct kvm_vcpu *vcpu,
enum kvm_arch_timers tmr,
--
2.34.1
