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Re: [Xen-devel] [PATCH v4 01/10] x86/hvm: Scale host TSC when setting/getting guest TSC

On 01/18/2016 08:39 AM, Jan Beulich wrote:
On 17.01.16 at 22:58, <haozhong.zhang@xxxxxxxxx> wrote:
The existing hvm_[set|get]_guest_tsc_fixed() calculate the guest TSC by
adding the TSC offset to the host TSC. When the TSC scaling is enabled,
the host TSC should be scaled first. This patch adds the scaling logic
to those two functions.

Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Signed-off-by: Haozhong Zhang <haozhong.zhang@xxxxxxxxx>
Changes in v4:
  (addressing Jan Beulich's comments)
  * Remove redundant check of cpu_has_tsc_ratio in svm_scale_tsc().
This would better have caused Boris' R-b tag to get dropped, or
at least I don't recall him having offered it to stay despite the
change. Boris - can you confirm one way or the other?

Yes, that's fine, my tag still stands.


  * Move check of d->arch.vtsc in svm_scale_tsc() to callers.
No d->arch.vtsc instances appear anywhere in this patch, so the
wording is confusing. Indeed the two callers already check this (or
really sit on suitable "else" paths), so at least the patch is correct.


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