Re: [PATCH v7 21/22] TEST(do-not-upstream): fake qemu-virt PMU events for cdeleg counter-mask testing

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The patch introduces fake PMU events intended solely for testing and unconditionally pollutes the production sysfs ABI.
--

commit 4ceddd2e5a59573074b3f2f8f712ad1f99946ae0
Author: Atish Patra <atishp@meta.com>

TEST(do-not-upstream): fake qemu-virt PMU events for cdeleg counter-mask testing

This commit adds fake PMU event codes to exercise counter-delegation allocation
and counter-mask constraints in QEMU. It unconditionally exposes these test
events to the user by adding them to the driver's event group.

> diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
> index 3cb7a1f4035ef..13a9f1fe42936 100644
> --- a/drivers/perf/riscv_pmu_sbi.c
> +++ b/drivers/perf/riscv_pmu_sbi.c

[ ... ]

> @@ -499,6 +505,9 @@ static struct attribute *qemu_virt_event_group[] = {
>  	RVPMU_EVENT_ATTR_PTR(dTLB_load_miss),
>  	RVPMU_EVENT_ATTR_PTR(dTLB_store_miss),
>  	RVPMU_EVENT_ATTR_PTR(iTLB_load_miss),
> +	RVPMU_EVENT_ATTR_PTR(fake_any),
> +	RVPMU_EVENT_ATTR_PTR(fake_ctr3),
> +	RVPMU_EVENT_ATTR_PTR(fake_ctr34),

[Severity: Medium]
Is it intended to leave these test-only events unconditionally exposed in the
production sysfs ABI?

Although the patch is explicitly marked as do-not-upstream, these fake events
are added directly to qemu_virt_event_group without being cleaned up later in
the series. This will visibly alter userspace tools like perf list on standard
RISC-V virtual workloads.

Could these test artifacts be separated from the mainline driver or removed
entirely if this series is routed upstream?

>  	NULL,
>  };

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260622-counter_delegation-v7-0-0ba2fd34614e@meta.com?part=21