linux-kernel - Re: [PATCH v2 03/11] KVM: x86: emulator: remove assign_eip

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Message-ID: <YtiVH83GZwMkSJP1@google.com>
Date:   Wed, 20 Jul 2022 23:51:59 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Maxim Levitsky <mlevitsk@...hat.com>
Cc:     kvm@...r.kernel.org, x86@...nel.org,
        Kees Cook <keescook@...omium.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        linux-kernel@...r.kernel.org, "H. Peter Anvin" <hpa@...or.com>,
        Borislav Petkov <bp@...en8.de>, Joerg Roedel <joro@...tes.org>,
        Ingo Molnar <mingo@...hat.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>
Subject: Re: [PATCH v2 03/11] KVM: x86: emulator: remove assign_eip_near/far

On Tue, Jun 21, 2022, Maxim Levitsky wrote:
> Now the assign_eip_far just updates the emulation mode in addition to
> updating the rip, it doesn't make sense to keep that function.
> 
> Move mode update to the callers and remove these functions.

I disagree, IMO there's a lot of value in differentiating between near and far.
Yeah, the assign_eip_near() wrapper is kinda silly, but have that instead of
a bare assign_eip() documents that e.g. jmp_rel() is a near jump and that it's
not missing an update.