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From: Wanpeng Li <kernellwp@gmail.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: LKML <linux-kernel@vger.kernel.org>, kvm <kvm@vger.kernel.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Tim Shearer" <tshearer@advaoptical.com>,
	"Liran Alon" <liran.alon@oracle.com>
Subject: Re: [PATCH 0/3] KVM: VMX: Allow to disable ioport intercept per-VM by userspace
Date: Sat, 12 May 2018 09:03:02 +0800	[thread overview]
Message-ID: <CANRm+CwkeQTLSOAWDMz8J+Ng5e6FPWABE94wWLZ2vbYA15H1DA@mail.gmail.com> (raw)
In-Reply-To: <20180511154019.GG27459@char.us.oracle.com>

2018-05-11 23:40 GMT+08:00 Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>:
> On Mon, Apr 16, 2018 at 10:45:59PM -0700, Wanpeng Li wrote:
>> Tim Shearer reported that "There is a guest which is running a packet
>> forwarding app based on the DPDK (dpdk.org). The packet receive routine
>> writes to 0xc070 using glibc's "outw_p" function which does an additional
>> write to I/O port 0x80. It does this write for every packet that's
>> received, causing a flood of KVM userspace context switches". He uses
>> mpstat to observe a CPU performing L2 packet forwarding on a pinned
>> guest vCPU, the guest time is 95 percent when allowing I/O port 0x80
>> bypass, however, it is 65.78 percent when I/O port 0x80 bypss is
>> disabled.
>>
>> This patchset introduces per-VM I/O permission bitmaps, the userspace
>> can disable the ioport intercept when they are more concern the
>> performance than the security.
>
> Could you kindly also add:
>
> Suggested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Yeah, both you and Liran give the original idea. :) Tim and Liran, any
review for the patchset?

Regards,
Wanpeng Li

  reply	other threads:[~2018-05-12  1:03 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-17  5:45 Wanpeng Li
2018-04-17  5:46 ` [PATCH 1/3] KVM: VMX: Introduce per-VM I/O permission bitmaps Wanpeng Li
2018-05-11 15:39   ` Konrad Rzeszutek Wilk
2018-05-15 21:55     ` Jim Mattson
2018-04-17  5:46 ` [PATCH 2/3] KVM: X86: Allow userspace to disable ioport intercept Wanpeng Li
2018-05-11 15:42   ` Konrad Rzeszutek Wilk
2018-05-11 15:43     ` Konrad Rzeszutek Wilk
2018-05-15 21:56       ` Jim Mattson
2018-05-16  1:13         ` Wanpeng Li
2018-04-17  5:46 ` [PATCH 3/3] KVM: VMX: Allow I/O port 0x80 bypass when userspace prefer Wanpeng Li
2018-05-11 15:44   ` Konrad Rzeszutek Wilk
2018-05-15 21:57     ` Jim Mattson
2018-05-08  7:55 ` [PATCH 0/3] KVM: VMX: Allow to disable ioport intercept per-VM by userspace Wanpeng Li
2018-05-08 16:14   ` Paolo Bonzini
2018-05-11 15:40 ` Konrad Rzeszutek Wilk
2018-05-12  1:03   ` Wanpeng Li [this message]
2018-05-14 13:48     ` Tim Shearer

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