Re: [PATCH v6 20/21] 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 adds synthetic test events explicitly marked 'TEST(do-not-upstream)' to the production RISC-V SBI PMU driver, polluting the UAPI.
--

commit 286ddcbf491d3a026da1733168d9b7d29bcd2fbe
Author: Atish Patra <atishp@meta.com>

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

This commit adds fake performance monitoring events to test counter delegation
and counter-mask constraints in Qemu. The events use codes that Qemu does not
model to verify allocation and programming behavior.

> diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
> index 74acac54328e0..3c0829c0a42ab 100644
> --- a/drivers/perf/riscv_pmu_sbi.c
> +++ b/drivers/perf/riscv_pmu_sbi.c
[ ... ]
> @@ -483,6 +489,9 @@ 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]
Does this code introduce a regression by exposing test functionality?

This patch is explicitly marked "do-not-upstream" and unconditionally adds
synthetic test events to the exposed Qemu platform pmu events array in
qemu_virt_event_group[].

Exposing these fake hardware events (fake-any, fake-ctr3, fake-ctr34)
to userspace pollutes the production sysfs uapi. These will appear in
perf list and could confuse users or automated tools.

>  	NULL,
>  };

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260608-counter_delegation-v6-0-285b72ed65a9@meta.com?part=20