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From: Ingo Molnar <mingo@kernel.org>
To: "Naveen N Rao (AMD)" <naveen@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	linux-kernel@vger.kernel.org, x86@kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Nikunj A Dadhania <nikunj@amd.com>,
	Manali Shukla <manali.shukla@amd.com>,
	Bharata B Rao <bharata@amd.com>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH v4 1/3] perf/amd/ibs: Limit the max EILVT register count for AMD family 0x10
Date: Thu, 23 Jul 2026 10:02:51 +0200	[thread overview]
Message-ID: <amHKq2HVbQrYoA2V@gmail.com> (raw)
In-Reply-To: <2d18caf834a2e66e4c6787e3c3058fd6bb6e5d3e.1784785046.git.naveen@kernel.org>


* Naveen N Rao (AMD) <naveen@kernel.org> 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@kernel.org>
> Tested-by: Manali Shukla <manali.shukla@amd.com>
> ---
>  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

  reply	other threads:[~2026-07-23  8:02 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-23  5:44 [PATCH v4 0/3] Support additional AMD EILVT registers Naveen N Rao (AMD)
2026-07-23  5:44 ` [PATCH v4 1/3] perf/amd/ibs: Limit the max EILVT register count for AMD family 0x10 Naveen N Rao (AMD)
2026-07-23  8:02   ` Ingo Molnar [this message]
2026-07-23  5:44 ` [PATCH v4 2/3] x86/apic: Introduce a variable to track the number of EILVT registers Naveen N Rao (AMD)
2026-07-23  5:44 ` [PATCH v4 3/3] x86/apic: Drop APIC_EILVT_NR_MAX Naveen N Rao (AMD)

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