linux-kernel - Re: [PATCH] KVM: x86/mmu: improve robustness of some functions

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Message-ID: <99258705-ff9e-aa0c-ba58-da87df760655@redhat.com>
Date:   Mon, 25 Jan 2021 10:58:43 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Stephen Zhang <stephenzhangzsd@...il.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        seanjc@...gle.com, wanpengli@...cent.com, jmattson@...gle.com,
        joro@...tes.org, tglx@...utronix.de, mingo@...hat.com,
        bp@...en8.de, x86@...nel.org, hpa@...or.com
Subject: Re: [PATCH] KVM: x86/mmu: improve robustness of some functions

On 25/01/21 10:54, Vitaly Kuznetsov wrote:
> 
> What if we do something like (completely untested):
> 
> diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
> index bfc6389edc28..5ec15e4160b1 100644
> --- a/arch/x86/kvm/mmu/mmu_internal.h
> +++ b/arch/x86/kvm/mmu/mmu_internal.h
> @@ -12,7 +12,7 @@
>  extern bool dbg;
>  
>  #define pgprintk(x...) do { if (dbg) printk(x); } while (0)
> -#define rmap_printk(x...) do { if (dbg) printk(x); } while (0)
> +#define rmap_printk(fmt, args...) do { if (dbg) printk("%s: " fmt, __func__, ## args); } while (0)
>  #define MMU_WARN_ON(x) WARN_ON(x)
>  #else
>  #define pgprintk(x...) do { } while (0)
> 
> and eliminate the need to pass '__func__,' explicitly? We can probably
> do the same to pgprintk().

Nice indeed.  Though I wonder if anybody has ever used these.  For those 
that I actually needed in the past I created tracepoints instead.

Paolo