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Message-ID: <20220415065041.GC2961@anparri> Date: Fri, 15 Apr 2022 08:50:41 +0200 From: Andrea Parri <parri.andrea@...il.com> To: "Michael Kelley (LINUX)" <mikelley@...rosoft.com> Cc: KY Srinivasan <kys@...rosoft.com>, Haiyang Zhang <haiyangz@...rosoft.com>, Stephen Hemminger <sthemmin@...rosoft.com>, Wei Liu <wei.liu@...nel.org>, Dexuan Cui <decui@...rosoft.com>, Stefano Garzarella <sgarzare@...hat.com>, David Miller <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, "linux-hyperv@...r.kernel.org" <linux-hyperv@...r.kernel.org>, "virtualization@...ts.linux-foundation.org" <virtualization@...ts.linux-foundation.org>, "netdev@...r.kernel.org" <netdev@...r.kernel.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org> Subject: Re: [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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