On Thu, May 23, 2024 at 04:04:13PM +0000, Sebastian Ene wrote:
> Request a PPI for each vCPU during probe which will be used by the host
> to communicate a stall detected event on the vCPU. When the host raises
> this interrupt from the virtual machine monitor, the guest is expected to
> handle the interrupt and panic.
>
> Signed-off-by: Sebastian Ene <sebastianene@xxxxxxxxxx>
> ---
> drivers/misc/vcpu_stall_detector.c | 41 ++++++++++++++++++++++++++++--
> 1 file changed, 39 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/misc/vcpu_stall_detector.c b/drivers/misc/vcpu_stall_detector.c
> index e2015c87f03f..c580cd7fd225 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");
platform_irq_count() either returns a number or EPROBE_DEFER, I don't
think emitting an error on deferred probe is the correct thing to do
here?
> + ret = num_irqs;
> + goto err;
> + } else if (num_irqs > 1) {
> + dev_err(&pdev->dev, "Multipple irqs detected\n");
Typo. I don't really see why you're going to this level of complexity
though, why aren't you just doing a single get_irq_optional()?
> + 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 void 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);
> }
> --
> 2.45.1.288.g0e0cd299f1-goog
>
>
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