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From:   Dexuan Cui <decui@microsoft.com>
To:     Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
CC:     KY Srinivasan <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        "sashal@kernel.org" <sashal@kernel.org>,
        "bhelgaas@google.com" <bhelgaas@google.com>,
        "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
        "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Michael Kelley <mikelley@microsoft.com>
Subject: RE: [PATCH 4/4] PCI: hv: Change pci_protocol_version to per-hbus
Thread-Topic: [PATCH 4/4] PCI: hv: Change pci_protocol_version to per-hbus
Thread-Index: AQHVdIeFCShWsTFDfkCdYqKWFRgLg6c/GIZA
Date:   Fri, 27 Sep 2019 07:01:07 +0000
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> From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Sent: Thursday, September 26, 2019 9:29 AM
>=20
> On Wed, Sep 11, 2019 at 11:38:23PM +0000, Dexuan Cui wrote:
> > A VM can have multiple hbus. It looks incorrect for the second hbus's
> > hv_pci_protocol_negotiation() to set the global variable
> > 'pci_protocol_version' (which was set by the first hbus), even if the
> > same value is written.
> >
> > Signed-off-by: Dexuan Cui <decui@microsoft.com>
>=20
> This is a fix that seems unrelated to the rest of the series.

Correct.
=20
> AFAICS the version also affects code paths in the driver, which
> means that in case you have busses with different versions the
> current code is wrong in this respect.

Correct.

> You have to capture this concept in the commit log, it reads as
> an optional change but it looks like a potential bug.
>=20
> Lorenzo

Agreed. Let me improve the commit log in v2.

Thanks,
-- Dexuan