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From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Wanpeng Li <kernellwp@gmail.com>
Cc: linux-kernel@vger.kernel.org, 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: Fri, 11 May 2018 11:40:19 -0400	[thread overview]
Message-ID: <20180511154019.GG27459@char.us.oracle.com> (raw)
In-Reply-To: <1523943962-25415-1-git-send-email-wanpengli@tencent.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>

Thank you.

  parent reply	other threads:[~2018-05-11 15:40 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-17  5:45 [PATCH 0/3] KVM: VMX: Allow to disable ioport intercept per-VM by userspace 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 [this message]
2018-05-12  1:03   ` Wanpeng Li
2018-05-14 13:48     ` Tim Shearer

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