linux-kernel - Re: [PATCH v2 3/4] x86/paravirt: switch mixed paravirt/alternative calls to alternative

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Message-ID: <20231016142930.GE33217@noisy.programming.kicks-ass.net>
Date:   Mon, 16 Oct 2023 16:29:30 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Juergen Gross <jgross@...e.com>
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org,
        virtualization@...ts.linux-foundation.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "H. Peter Anvin" <hpa@...or.com>, Ajay Kaher <akaher@...are.com>,
        Alexey Makhalov <amakhalov@...are.com>,
        VMware PV-Drivers Reviewers <pv-drivers@...are.com>
Subject: Re: [PATCH v2 3/4] x86/paravirt: switch mixed paravirt/alternative
 calls to alternative_2

On Mon, Oct 16, 2023 at 02:39:32PM +0200, Juergen Gross wrote:
> Instead of stacking alternative and paravirt patching, use the new
> ALT_FLAG_CALL flag to switch those mixed calls to pure alternative
> handling.
> 
> This eliminates the need to be careful regarding the sequence of
> alternative and paravirt patching.
> 
> For call depth tracking callthunks_setup() needs to be adapted to patch
> calls at alternative patching sites instead of paravirt calls.
> 
> Signed-off-by: Juergen Gross <jgross@...e.com>

I cannot help but feel this would've been better as two patches, one
introducing ALT_NOT_XEN and then a second with the rest.

Regardless,

Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>