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hv_utils: Set the maximum packet size for VSS driver to the length of the receive buffer

Vitaly Kuznetsov requested to merge vkuznets/centos-stream-9:bug1996628 into main

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1996628

commit 9d68cd9120e4e3af38f843e165631c323b86b4e4
Author: Vitaly Kuznetsov <vkuznets@redhat.com>
Date:   Wed Aug 25 15:38:57 2021 +0200

    hv_utils: Set the maximum packet size for VSS driver to the length of the receive buffer

    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>
    Reviewed-by: Michael Kelley <mikelley@microsoft.com>
    Link: https://lore.kernel.org/r/20210825133857.847866-1-vkuznets@redhat.com
    Signed-off-by: Wei Liu <wei.liu@kernel.org>

Signed-off-by: Vitaly Kuznetsov vkuznets@redhat.com

Edited by Vitaly Kuznetsov

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