Re: [PATCH] arm64: KVM: Save two instructions in __guest_enter()

From	Christoffer Dall <christoffer.dall@linaro.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH] arm64: KVM: Save two instructions in __guest_enter()
Date	2016-08-25 15:40 +0200
Message-ID	<sa32W-1xi-15@gated-at.bofh.it> (permalink)
References	<s4qlz-6S2-15@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

Hi Shanker,

On Tue, Aug 09, 2016 at 08:15:36PM -0500, Shanker Donthineni wrote:
> We are doing an unnecessary stack push/pop operation when restoring
> the guest registers x0-x18 in __guest_enter(). This patch saves the
> two instructions by using x18 as a base register. No need to store
> the vcpu context pointer in stack because it is redundant and not
> being used anywhere, the same information is available in tpidr_el2.

Does this have any measureable benefit?

Thanks,
-Christoffer

Back to linux.kernel | Previous | Next — Next in thread | Find similar | Unroll thread

Thread

Re: [PATCH] arm64: KVM: Save two instructions in __guest_enter() Christoffer Dall <christoffer.dall@linaro.org> - 2016-08-25 15:40 +0200
  Re: [PATCH] arm64: KVM: Save two instructions in __guest_enter() Shanker Donthineni <shankerd@codeaurora.org> - 2016-08-29 17:30 +0200
    Re: [PATCH] arm64: KVM: Save two instructions in __guest_enter() Christoffer Dall <christoffer.dall@linaro.org> - 2016-08-29 20:20 +0200

csiph-web