lkml.org 
[lkml]   [2018]   [May]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [PATCH 0/3] KVM: VMX: Allow to disable ioport intercept per-VM by userspace
    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

    \
     
     \ /
      Last update: 2018-05-12 03:03    [W:2.113 / U:0.176 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site