From: "Antti Järvinen" <antti.jarvinen@gmail.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
Alex Williamson <alex.williamson@redhat.com>,
Murali Karicheri <m-karicheri2@ti.com>,
Kishon Vijay Abraham I <kishon@ti.com>
Subject: Re: [PATCH] PCI: quirk for preventing bus reset on TI C667X
Date: Tue, 26 Jan 2021 13:22:18 +0200 [thread overview]
Message-ID: <35612e76-0b97-7bb4-60b7-88ae6d53f0be@gmail.com> (raw)
In-Reply-To: <20210121235547.GA2705432@bjorn-Precision-5520>
On 22.1.2021 1.55, Bjorn Helgaas wrote:>
> It looks like we would probably be trying a Secondary Bus Reset using
> the bridge leading to the C667X. Can you confirm?
Yes, this is my understanding too.
> Wonder if you
> could try doing what pci_reset_secondary_bus() does by hand:
>
I tried this by hand. It looks that result is same as through VFIO.
# cat sbr.sh
BRIDGE=10:00.0
C667X=11:00.0
setpci -s$C667X VENDOR_ID.w
VAL=$(setpci -s$BRIDGE BRIDGE_CONTROL.w)
echo $VAL
setpci -s$BRIDGE BRIDGE_CONTROL.w=$(($VAL | 0x40))
sleep 1
setpci -s$BRIDGE BRIDGE_CONTROL.w=$VAL
sleep 1
setpci -s$C667X VENDOR_ID.w=0
setpci -s$C667X VENDOR_ID.w
# ./sbr.sh
104c
0003
ffff
> # BRIDGE=... # PCI address, e.g., 00:1c.0
> # C667X=...
> # setpci -s$C667X VENDOR_ID.w
> # setpci -s$BRIDGE BRIDGE_CONTROL.w # prints "val"
> # setpci -s$BRIDGE BRIDGE_CONTROL.w= # val | 0x40 (set SBR)
> # sleep 1
> # setpci -s$BRIDGE BRIDGE_CONTROL.w= # val (clear SBR)
> # sleep 1
> # setpci -s$C667X VENDOR_ID.w=0
> # setpci -s$C667X VENDOR_ID.w
>
> If we use this quirk and avoid the reset, I assume that means
> assigning the device to VMs with VFIO will leak state between VMs?
I think this is true.
next prev parent reply other threads:[~2021-01-26 12:06 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-12 15:36 [PATCH] PCI: quirk for preventing bus reset on TI C667X Antti Järvinen
2021-01-21 23:55 ` Bjorn Helgaas
2021-01-26 11:22 ` Antti Järvinen [this message]
2021-01-29 23:49 ` Bjorn Helgaas
2021-02-17 21:18 ` Bjorn Helgaas
2021-02-28 13:53 ` [PATCH v2] " Antti Järvinen
2021-03-07 0:22 ` Krzysztof Wilczyński
2021-03-08 14:21 ` [PATCH v3] PCI: Add " Antti Järvinen
2021-03-12 21:09 ` Bjorn Helgaas
2021-03-15 10:26 ` [PATCH v4] " Antti Järvinen
2021-04-19 12:44 ` Kishon Vijay Abraham I
2021-05-27 23:07 ` Bjorn Helgaas
2021-03-15 10:45 ` [PATCH v3] " Antti Järvinen
2021-03-08 14:28 ` [PATCH v2] PCI: " Antti Järvinen
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