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SubjectRe: [RFC PATCH 4/6] hv_sock: Initialize send_buf in hvs_stream_enqueue()
> > @@ -655,7 +655,7 @@ static ssize_t hvs_stream_enqueue(struct vsock_sock *vsk,
> > struct msghdr *msg,
> >
> > BUILD_BUG_ON(sizeof(*send_buf) != HV_HYP_PAGE_SIZE);
> >
> > - send_buf = kmalloc(sizeof(*send_buf), GFP_KERNEL);
> > + send_buf = kzalloc(sizeof(*send_buf), GFP_KERNEL);
>
> Is this change really needed?

The idea was...


> All fields are explicitly initialized, and in the data
> array, only the populated bytes are copied to the ring buffer. There should not
> be any uninitialized values sent to the host. Zeroing the memory ahead of
> time certainly provides an extra protection (particularly against padding bytes,
> but there can't be any since the layout of the data is part of the protocol with
> Hyper-V).

Rather than keeping checking that...


> It is expensive protection to zero out 16K+ bytes every time we send
> out a small message.

Do this. ;-)

Will drop the patch.

Thanks,
Andrea

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