linux-kernel - Re: [PATCH] KVM: x86: Drop "cache" from user return MSR setter that skips WRMSR

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Message-ID: <aNvLkRZCZ1ckPhFa@yzhao56-desk.sh.intel.com>
Date: Tue, 30 Sep 2025 20:22:41 +0800
From: Yan Zhao <yan.y.zhao@...el.com>
To: Sean Christopherson <seanjc@...gle.com>
CC: Paolo Bonzini <pbonzini@...hat.com>, <kvm@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, Xiaoyao Li <xiaoyao.li@...el.com>, "Rick
 Edgecombe" <rick.p.edgecombe@...el.com>
Subject: Re: [PATCH] KVM: x86: Drop "cache" from user return MSR setter that
 skips WRMSR

On Fri, Sep 19, 2025 at 02:42:59PM -0700, Sean Christopherson wrote:
> Rename kvm_user_return_msr_update_cache() to __kvm_set_user_return_msr()
> and use the helper kvm_set_user_return_msr() to make it obvious that the
> double-underscores version is doing a subset of the work of the "full"
> setter.
> 
> While the function does indeed update a cache, the nomenclature becomes
> slightly misleading when adding a getter[1], as the current value isn't
> _just_ the cached value, it's also the value that's currently loaded in
> hardware.
Nit:

For TDX, "it's also the value that's currently loaded in hardware" is not true.

> Opportunistically rename "index" to "slot" in the prototypes.  The user-
> return APIs deliberately use "slot" to try and make it more obvious that
> they take the slot within the array, not the index of the MSR.
> 
> No functional change intended.

Reviewed-by: Yan Zhao <yan.y.zhao@...el.com>

> Cc: Yan Zhao <yan.y.zhao@...el.com>
> Cc: Xiaoyao Li <xiaoyao.li@...el.com>
> Cc: Rick Edgecombe <rick.p.edgecombe@...el.com>
> Link: https://lore.kernel.org/all/aM2EvzLLmBi5-iQ5@google.com [1]
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>