Messages in this thread | | | Subject | Re: [PATCH] KVM: VMX: drop I/O permission bitmaps | From | Quan Xu <> | Date | Mon, 11 Dec 2017 13:37:55 +0800 |
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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
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