lkml.org 
[lkml]   [2017]   [Dec]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] KVM: VMX: drop I/O permission bitmaps
From
Date


On 2017/12/09 01:31, Jim Mattson wrote:
> On Fri, Dec 8, 2017 at 2:22 AM, Quan Xu <quan.xu0@gmail.com> wrote:
>> From: Quan Xu <quan.xu0@gmail.com>
>>
>> Since KVM removes the only I/O port 0x80 bypass on Intel hosts,
>> clear CPU_BASED_USE_IO_BITMAPS and set CPU_BASED_UNCOND_IO_EXITING
>> bit. Then these I/O permission bitmaps are not used at all, so
>> drop I/O permission bitmaps.
>>
>> Signed-off-by: Jim Mattson <jmattson@google.com>
>> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
>> Signed-off-by: Quan Xu <quan.xu0@gmail.com>
>> ---
>> arch/x86/kvm/vmx.c | 17 +----------------
>> 1 files changed, 1 insertions(+), 16 deletions(-)
>>
>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>> index 2fd9a8c..3e4f760 100644
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -771,8 +771,6 @@ enum segment_cache_field {
>> FIELD(HOST_FS_SELECTOR, host_fs_selector),
>> FIELD(HOST_GS_SELECTOR, host_gs_selector),
>> FIELD(HOST_TR_SELECTOR, host_tr_selector),
>> - FIELD64(IO_BITMAP_A, io_bitmap_a),
>> - FIELD64(IO_BITMAP_B, io_bitmap_b),
> These two lines should stay.
Jim, could you explain why these two lines should stay?


IIUC, the main concern is from  nested virtualization, which still uses
io_bitmap_a/io_bitmap_b..
if so, we really need to further clean up these code, as

CPU_BASED_USE_IO_BITMAPS is clear, and CPU_BASED_UNCOND_IO_EXITING is set for both L0/L2. after new patches which I mentioned
in this thread.

right?

Alibaba Cloud
Quan



\
 
 \ /
  Last update: 2017-12-11 06:38    [W:0.105 / U:1.040 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site