misc: Register a PPI for the vcpu stall detection virtual device
Request a PPI for each vCPU during probe which will be used by the host
to communicate a stall detected on the vCPU. When the host raises this
interrupt, the guest is expected to abort the execution and panic.
Signed-off-by: Sebastian Ene <sebastianene@google.com>
diff --git a/Documentation/devicetree/bindings/misc/qemu,vcpu-stall-detector.yaml b/Documentation/devicetree/bindings/misc/qemu,vcpu-stall-detector.yaml
index 1aebeb6..c656005 100644
--- a/Documentation/devicetree/bindings/misc/qemu,vcpu-stall-detector.yaml
+++ b/Documentation/devicetree/bindings/misc/qemu,vcpu-stall-detector.yaml
@@ -29,6 +29,9 @@
Defaults to 10 if unset.
default: 10
+ interrupts:
+ maxItems: 1
+
timeout-sec:
description: |
The stall detector expiration timeout measured in seconds.
@@ -43,9 +46,12 @@
examples:
- |
+ #include <dt-bindings/interrupt-controller/arm-gic.h>
+
vmwdt@9030000 {
compatible = "qemu,vcpu-stall-detector";
reg = <0x9030000 0x10000>;
clock-frequency = <10>;
timeout-sec = <8>;
+ interrupts = <GIC_PPI 15 0xf01>;
};
diff --git a/drivers/misc/vcpu_stall_detector.c b/drivers/misc/vcpu_stall_detector.c
index 6479c96..fa0cc4e 100644
--- a/drivers/misc/vcpu_stall_detector.c
+++ b/drivers/misc/vcpu_stall_detector.c
@@ -32,6 +32,7 @@
struct vcpu_stall_detect_config {
u32 clock_freq_hz;
u32 stall_timeout_sec;
+ int ppi_irq;
void __iomem *membase;
struct platform_device *dev;
@@ -77,6 +78,12 @@ vcpu_stall_detect_timer_fn(struct hrtimer *hrtimer)
return HRTIMER_RESTART;
}
+static irqreturn_t vcpu_stall_detector_irq(int irq, void *dev)
+{
+ panic("vCPU stall detector");
+ return IRQ_HANDLED;
+}
+
static int start_stall_detector_cpu(unsigned int cpu)
{
u32 ticks, ping_timeout_ms;
@@ -132,7 +139,7 @@ static int stop_stall_detector_cpu(unsigned int cpu)
static int vcpu_stall_detect_probe(struct platform_device *pdev)
{
- int ret;
+ int ret, irq, num_irqs;
struct resource *r;
void __iomem *membase;
u32 clock_freq_hz = VCPU_STALL_DEFAULT_CLOCK_HZ;
@@ -169,9 +176,32 @@ static int vcpu_stall_detect_probe(struct platform_device *pdev)
vcpu_stall_config = (struct vcpu_stall_detect_config) {
.membase = membase,
.clock_freq_hz = clock_freq_hz,
- .stall_timeout_sec = stall_timeout_sec
+ .stall_timeout_sec = stall_timeout_sec,
+ .ppi_irq = -1,
};
+ num_irqs = platform_irq_count(pdev);
+ if (num_irqs < 0) {
+ dev_err(&pdev->dev, "Failed to get irqs\n");
+ ret = num_irqs;
+ goto err;
+ } else if (num_irqs > 1) {
+ dev_err(&pdev->dev, "Multipple irqs detected\n");
+ ret = -EINVAL;
+ goto err;
+ } else if (num_irqs == 1) {
+ irq = platform_get_irq(pdev, 0);
+ if ((irq > 0) && irq_is_percpu_devid(irq)) {
+ ret = request_percpu_irq(irq,
+ vcpu_stall_detector_irq,
+ "vcpu_stall_detector",
+ vcpu_stall_detectors);
+ if (!ret)
+ vcpu_stall_config.ppi_irq = irq;
+
+ }
+ }
+
ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
"virt/vcpu_stall_detector:online",
start_stall_detector_cpu,
@@ -184,6 +214,9 @@ static int vcpu_stall_detect_probe(struct platform_device *pdev)
vcpu_stall_config.hp_online = ret;
return 0;
err:
+ if (vcpu_stall_config.ppi_irq > 0)
+ free_percpu_irq(vcpu_stall_config.ppi_irq,
+ vcpu_stall_detectors);
return ret;
}
@@ -193,6 +226,10 @@ static int vcpu_stall_detect_remove(struct platform_device *pdev)
cpuhp_remove_state(vcpu_stall_config.hp_online);
+ if (vcpu_stall_config.ppi_irq > 0)
+ free_percpu_irq(vcpu_stall_config.ppi_irq,
+ vcpu_stall_detectors);
+
for_each_possible_cpu(cpu)
stop_stall_detector_cpu(cpu);
