Re: [PATCH v4 1/3] perf/amd/ibs: Limit the max EILVT register count for AMD family 0x10

From: Ingo Molnar

Date: Thu Jul 23 2026 - 04:04:57 EST



* Naveen N Rao (AMD) <naveen@xxxxxxxxxx> wrote:

> For AMD family 0x10, EILVT offsets are not assigned by BIOS and is
> instead assigned by picking the next available EILVT offset. Use the
> maximum EILVT count for family 0x10 (APIC_EILVT_NR_AMD_10H) rather than
> an arbitrary maximum EILVT count when looking for the next available
> EILVT offset.
>
> Signed-off-by: Naveen N Rao (AMD) <naveen@xxxxxxxxxx>
> Tested-by: Manali Shukla <manali.shukla@xxxxxxx>
> ---
> arch/x86/events/amd/ibs.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
> index 3531f9c23b8c..555912ac520f 100644
> --- a/arch/x86/events/amd/ibs.c
> +++ b/arch/x86/events/amd/ibs.c
> @@ -1839,13 +1839,13 @@ static void force_ibs_eilvt_setup(void)
>
> preempt_disable();
> /* find the next free available EILVT entry, skip offset 0 */
> - for (offset = 1; offset < APIC_EILVT_NR_MAX; offset++) {
> + for (offset = 1; offset < APIC_EILVT_NR_AMD_10H; offset++) {

Nit:

s/APIC_EILVT_NR_AMD_10H
/APIC_EILVT_NR_MAX_AMD_10H

to make it clear at first sight that this is a (family specific)
maximum, not some default count or other random value.

Thanks,

Ingo