From: Yazen Ghannam <yazen.ghannam@amd.com>
To: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
Mario Limonciello <mario.limonciello@amd.com>,
Filip Barczyk <filip.barczyk@pico.net>
Subject: Re: [PATCH 1/2] x86/amd_node: Fix AMD root device caching
Date: Tue, 21 Oct 2025 10:25:07 -0400 [thread overview]
Message-ID: <20251021142507.GA62725@yaz-khff2.amd.com> (raw)
In-Reply-To: <20251021141500.GDaPeVZJ8MaPbtTYv_@fat_crate.local>
On Tue, Oct 21, 2025 at 04:15:00PM +0200, Borislav Petkov wrote:
> On Tue, Oct 21, 2025 at 09:37:45AM -0400, Yazen Ghannam wrote:
> > It's correct that one of the root devices will be on bus 0x0. But that
> > device will be part of AMD node 0. So we still need to pick a root
> > device for the other, if any, AMD nodes in the system.
> >
> > For example, a system with 2 AMD nodes could have this:
> > Node 0 : 0x00 0x07 0x0e 0x15
> > Node 1 : 0x1c 0x23 0x2a 0x31
>
> Aha, so next question: isn't there a way to figure out which is the *first*
> PCI bus of a AMD node? My gut feeling tells me there should be some info
> somewhere which we can use...
>
Yep, that was one of the goals of the recent rework. I thought the DF
register held that info, but I was mistaken.
I haven't been able to find anything else. We can keep looking, but I
wanted to send out this patch as a fix in the meantime.
Thanks,
Yazen
next prev parent reply other threads:[~2025-10-21 14:25 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-30 16:45 [PATCH 0/2] AMD root search fix Yazen Ghannam
2025-09-30 16:45 ` [PATCH 1/2] x86/amd_node: Fix AMD root device caching Yazen Ghannam
2025-09-30 18:07 ` Mario Limonciello (AMD) (kernel.org)
2025-10-01 13:46 ` Yazen Ghannam
2025-10-07 17:30 ` Filip Barczyk
2025-10-07 17:37 ` Filip Barczyk
2025-10-21 12:29 ` Borislav Petkov
2025-10-21 13:37 ` Yazen Ghannam
2025-10-21 14:15 ` Borislav Petkov
2025-10-21 14:25 ` Yazen Ghannam [this message]
2025-10-22 11:13 ` Borislav Petkov
2025-10-22 13:19 ` Yazen Ghannam
2025-10-22 18:48 ` Borislav Petkov
2025-09-30 16:45 ` [PATCH 2/2] x86/amd_node: Use new root search helper Yazen Ghannam
2025-09-30 18:07 ` [PATCH 0/2] AMD root search fix Mario Limonciello (AMD) (kernel.org)
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