[MODERATED] [QUESTION] about vmx_l1d_flush_pages

[Nicolai Stange <nstange@suse.de>]

Hi,

I've got two questions related to the initialization of
vmx_l1d_flush_pages from v15 commit a47dd5f06714 ("x86/KVM/VMX: Add L1D
flush algorithm").

[Apologies for not replying properly -- I don't have the original mail].

1.) The
      [empty_zp] "r" (vmx_l1d_flush_pages)
    asm constraint in vmx_l1d_flush() seems to suggest that these pages
    are zeroed out. But AFAICS they're actually left uninitialized.
    Am I wrong or is this intended?

2.) With nested KVM, the vmx_l1d_flush_pages could be subject to KSM on
    the host. This means that the 16 vmx_l1d_flush_pages could get
    mapped to fewer host physical pages and that would break the L1d
    flush?

    If so, an obvious fix would be to initialize all 16 pages with
    a different pattern each.

Thanks,

Nicolai

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