Re: [PATCH v4 7/7] KVM: s390: selftests: Fix cmma selftest

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Outdated comments and function naming due to inline assembly changes.
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commit 007cfe6c8e5c96330ecd4725d320fa59c950105a
Author: Claudio Imbrenda <imbrenda@linux.ibm.com>

KVM: s390: selftests: Fix cmma selftest

The existing cmma selftest depended on the host allocating page tables
for all present memslots. Since the gmap rewrite, memory that is not
accessed by the guest might not have page tables allocated yet.

> diff --git a/tools/testing/selftests/kvm/s390/cmma_test.c b/tools/testing/selftests/kvm/s390/cmma_test.c
> index e39a724fe860e..04f34b7ec1279 100644
> --- a/tools/testing/selftests/kvm/s390/cmma_test.c
> +++ b/tools/testing/selftests/kvm/s390/cmma_test.c
> @@ -39,11 +39,14 @@ static void guest_do_one_essa(void)
>  {
>  	asm volatile(
>  		/* load TEST_DATA_START_GFN into r1 */
> +		"	xgr 1,1\n"
>  		"	llilf 1,%[start_gfn]\n"
>  		/* calculate the address from the gfn */
>  		"	sllg 1,1,12(0)\n"
>  		/* set the first page in TEST_DATA memslot to STABLE */
>  		"	.insn rrf,0xb9ab0000,2,1,1,0\n"
> +		"	agfi 1,0x100000\n"
> +		"	.insn rrf,0xb9ab0000,2,1,1,0\n"

[Severity: Low]
This isn't a bug, but with the addition of the second .insn instruction, the
code now accesses a second page. Should the inline comment and the function
name guest_do_one_essa (along with its docstring claiming it dirties exactly
one page) be updated to reflect that multiple pages are now being touched?

>  		/* hypercall */
>  		"	diag 0,0,0x501\n"
>  		"0:	j 0b"

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Sashiko AI review · https://sashiko.dev/#/patchset/20260619155154.307572-1-imbrenda@linux.ibm.com?part=7