From: Michael Kelley <mikelley@microsoft.com>
To: vkuznets <vkuznets@redhat.com>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>
Cc: Andres Beltran <lkmlabelt@gmail.com>,
"Andrea Parri (Microsoft)" <parri.andrea@gmail.com>,
Dexuan Cui <decui@microsoft.com>, Wei Liu <wei.liu@kernel.org>,
Stephen Hemminger <sthemmin@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
KY Srinivasan <kys@microsoft.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] hv_utils: Set the maximum packet size for VSS driver to the length of the receive buffer
Date: Wed, 25 Aug 2021 18:33:10 +0000 [thread overview]
Message-ID: <MWHPR21MB15931C94B84D62C451163BAFD7C69@MWHPR21MB1593.namprd21.prod.outlook.com> (raw)
In-Reply-To: <20210825133857.847866-1-vkuznets@redhat.com>
From: Vitaly Kuznetsov <vkuznets@redhat.com> Sent: Wednesday, August 25, 2021 6:39 AM
>
> Commit adae1e931acd ("Drivers: hv: vmbus: Copy packets sent by Hyper-V out
> of the ring buffer") introduced a notion of maximum packet size and for
> KVM and FCOPY drivers set it to the length of the receive buffer. VSS
> driver wasn't updated, this means that the maximum packet size is now
> VMBUS_DEFAULT_MAX_PKT_SIZE (4k). Apparently, this is not enough. I'm
> observing a packet of 6304 bytes which is being truncated to 4096. When
> VSS driver tries to read next packet from ring buffer it starts from the
> wrong offset and receives garbage.
>
> Set the maximum packet size to 'HV_HYP_PAGE_SIZE * 2' in VSS driver. This
> matches the length of the receive buffer and is in line with other utils
> drivers.
>
> Fixes: adae1e931acd ("Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring buffer")
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
> drivers/hv/hv_snapshot.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/hv/hv_snapshot.c b/drivers/hv/hv_snapshot.c
> index 2267bd4c3472..6018b9d1b1fb 100644
> --- a/drivers/hv/hv_snapshot.c
> +++ b/drivers/hv/hv_snapshot.c
> @@ -375,6 +375,7 @@ hv_vss_init(struct hv_util_service *srv)
> }
> recv_buffer = srv->recv_buffer;
> vss_transaction.recv_channel = srv->channel;
> + vss_transaction.recv_channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2;
>
> /*
> * When this driver loads, the user level daemon that
> --
> 2.31.1
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
next prev parent reply other threads:[~2021-08-25 18:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-25 13:38 [PATCH] hv_utils: Set the maximum packet size for VSS driver to the length of the receive buffer Vitaly Kuznetsov
2021-08-25 18:33 ` Michael Kelley [this message]
2021-08-25 19:02 ` Wei Liu
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