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From:   Huacai Chen <chenhuacai@gmail.com>
Date:   Mon, 8 Jun 2020 16:56:32 +0800
Message-ID: <CAAhV-H6v+tO6PCqjfDcecxk-mUk8YEmSDUMjOXMj1hL5=XSpSw@mail.gmail.com>
Subject: Re: [PATCH 19/21] KVM: MIPS: Drop @max param from mmu_topup_memory_cache()
To:     Sean Christopherson <sean.j.christopherson@intel.com>
Cc:     Marc Zyngier <maz@kernel.org>, Paul Mackerras <paulus@ozlabs.org>,
        Christian Borntraeger <borntraeger@de.ibm.com>,
        Janosch Frank <frankja@linux.ibm.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        James Morse <james.morse@arm.com>,
        Julien Thierry <julien.thierry.kdev@gmail.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        David Hildenbrand <david@redhat.com>,
        Cornelia Huck <cohuck@redhat.com>,
        Claudio Imbrenda <imbrenda@linux.ibm.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        kvmarm@lists.cs.columbia.edu,
        "open list:MIPS" <linux-mips@vger.kernel.org>,
        kvm <kvm@vger.kernel.org>, kvm-ppc@vger.kernel.org,
        LKML <linux-kernel@vger.kernel.org>,
        Peter Feiner <pfeiner@google.com>,
        Peter Shier <pshier@google.com>,
        Junaid Shahid <junaids@google.com>,
        Ben Gardon <bgardon@google.com>,
        Christoffer Dall <christoffer.dall@arm.com>
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Reviewed-by: Huacai Chen <chenhc@lemote.com>

On Sat, Jun 6, 2020 at 5:44 AM Sean Christopherson
<sean.j.christopherson@intel.com> wrote:
>
> Replace the @max param in mmu_topup_memory_cache() and instead use
> ARRAY_SIZE() to terminate the loop to fill the cache.  This removes a
> BUG_ON() and sets the stage for moving MIPS to the common memory cache
> implementation.
>
> No functional change intended.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
>  arch/mips/kvm/mmu.c | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c
> index 7dad7a293eae..94562c54b930 100644
> --- a/arch/mips/kvm/mmu.c
> +++ b/arch/mips/kvm/mmu.c
> @@ -25,15 +25,13 @@
>  #define KVM_MMU_CACHE_MIN_PAGES 2
>  #endif
>
> -static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
> -                                 int min, int max)
> +static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache, int min)
>  {
>         void *page;
>
> -       BUG_ON(max > KVM_NR_MEM_OBJS);
>         if (cache->nobjs >= min)
>                 return 0;
> -       while (cache->nobjs < max) {
> +       while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
>                 page = (void *)__get_free_page(GFP_KERNEL);
>                 if (!page)
>                         return -ENOMEM;
> @@ -711,8 +709,7 @@ static int kvm_mips_map_page(struct kvm_vcpu *vcpu, unsigned long gpa,
>                 goto out;
>
>         /* We need a minimum of cached pages ready for page table creation */
> -       err = mmu_topup_memory_cache(memcache, KVM_MMU_CACHE_MIN_PAGES,
> -                                    KVM_NR_MEM_OBJS);
> +       err = mmu_topup_memory_cache(memcache, KVM_MMU_CACHE_MIN_PAGES);
>         if (err)
>                 goto out;
>
> @@ -796,8 +793,7 @@ static pte_t *kvm_trap_emul_pte_for_gva(struct kvm_vcpu *vcpu,
>         int ret;
>
>         /* We need a minimum of cached pages ready for page table creation */
> -       ret = mmu_topup_memory_cache(memcache, KVM_MMU_CACHE_MIN_PAGES,
> -                                    KVM_NR_MEM_OBJS);
> +       ret = mmu_topup_memory_cache(memcache, KVM_MMU_CACHE_MIN_PAGES);
>         if (ret)
>                 return NULL;
>
> --
> 2.26.0
>