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From: Siddharth Chandrasekaran <sidcha@amazon.de>
To: Wei Liu <wei.liu@kernel.org>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
	Siddharth Chandrasekaran <sidcha.dev@gmail.com>,
	Liran Alon <liran@amazon.com>,
	Ioannis Aslanidis <iaslan@amazon.de>,
	<linux-hyperv@vger.kernel.org>, <linux-arch@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Dexuan Cui <decui@microsoft.com>, Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH] asm-generic/hyperv: Fix struct hv_message_header ordering
Date: Thu, 29 Jul 2021 16:26:54 +0200	[thread overview]
Message-ID: <20210729142652.GA25242@uc8bbc9586ea454.ant.amazon.com> (raw)
In-Reply-To: <20210729140705.wj5tokeq6lkxm2yy@liuwe-devbox-debian-v2>

On Thu, Jul 29, 2021 at 02:07:05PM +0000, Wei Liu wrote:
> On Thu, Jul 29, 2021 at 03:52:46PM +0200, Vitaly Kuznetsov wrote:
> > Siddharth Chandrasekaran <sidcha@amazon.de> writes:
> >
> > > According to Hyper-V TLFS Version 6.0b, struct hv_message_header members
> > > should be defined in the order:
> > >
> > >     message_type, reserved, message_flags, payload_size
> > >
> > > but we have it defined in the order:
> > >
> > >     message_type, payload_size, message_flags, reserved
> > >
> > > that is, the payload_size and reserved members swapped.
> >
> > Indeed,
> >
> > typedef struct
> > {
> >       HV_MESSAGE_TYPE MessageType;
> >       UINT16 Reserved;
> >       HV_MESSAGE_FLAGS MessageFlags;
> >       UINT8 PayloadSize;
> >       union
> >       {
> >               UINT64 OriginationId;
> >               HV_PARTITION_ID Sender;
> >               HV_PORT_ID Port;
> >       };
> > } HV_MESSAGE_HEADER;
> 
> Well. I think TLFS is wrong. Let me ask around.

TBH, I hadn't considered that possibility :). I assumed it was a
regression on our side. But I spent some time tracing the history of that
struct all the way back to when it was in staging (in 2009) and now I'm
inclined to believe a later version of TLFS is at fault here.

Based on what we decide in this thread, I will open an issue on the TLFS
GitHub repository.

~ Sid.



Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879




  reply	other threads:[~2021-07-29 14:27 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-29 13:37 Siddharth Chandrasekaran
2021-07-29 13:52 ` Vitaly Kuznetsov
2021-07-29 14:07   ` Wei Liu
2021-07-29 14:26     ` Siddharth Chandrasekaran [this message]
2021-07-29 16:56       ` Wei Liu
2021-07-30  9:35         ` Siddharth Chandrasekaran
2021-07-31  6:51 ` [asm] b5b51922df: kvm-unit-tests.hyperv_stimer.fail kernel test robot

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