linux-kernel - Re: [RFC PATCH v3 2/2] KVM: x86/mmu: replace BUG() with KVM

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Date:   Mon, 28 Nov 2022 11:26:47 -0800
From:   Mingwei Zhang <mizhang@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Nagareddy Reddy <nspreddy@...gle.com>,
        Jim Mattson <jmattson@...gle.com>,
        David Matlack <dmatlack@...gle.com>
Subject: Re: [RFC PATCH v3 2/2] KVM: x86/mmu: replace BUG() with KVM_BUG() in
 shadow mmu

> Something like this?
>
> ---
>  arch/x86/kvm/mmu/mmu.c | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index b5a44b8f5f7b..12790ccb8731 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -954,15 +954,16 @@ static void pte_list_remove(struct kvm *kvm, u64 *spte,
>         struct pte_list_desc *prev_desc;
>         int i;
>
> -       if (!rmap_head->val) {
> -               pr_err("%s: %p 0->BUG\n", __func__, spte);
> -               BUG();
> -       } else if (!(rmap_head->val & 1)) {
> +       if (KVM_BUG(!rmap_head->val, kvm, "rmap for %p is empty", spte))
> +               return;
> +
> +       if (!(rmap_head->val & 1)) {
>                 rmap_printk("%p 1->0\n", spte);
> -               if ((u64 *)rmap_head->val != spte) {
> -                       pr_err("%s:  %p 1->BUG\n", __func__, spte);
> -                       BUG();
> -               }
> +
> +               if (KVM_BUG((u64 *)rmap_head->val != spte, kvm,
> +                           "single rmap for %p doesn't match", spte))
> +                       return;
> +
>                 rmap_head->val = 0;
>         } else {
>                 rmap_printk("%p many->many\n", spte);
> @@ -979,8 +980,7 @@ static void pte_list_remove(struct kvm *kvm, u64 *spte,
>                         prev_desc = desc;
>                         desc = desc->more;
>                 }
> -               pr_err("%s: %p many->many\n", __func__, spte);
> -               BUG();
> +               KVM_BUG(true, kvm, "no rmap for %p (many->many)", spte);
>         }
>  }
>
>
> base-commit: d74237e747db7f9f27e821e6683d58185e846378
> --
>

make sense, will update that in the next version.