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Date:   Thu, 18 May 2023 14:14:46 +0200
From:   "Arnd Bergmann" <arnd@arndb.de>
To:     "Marc Zyngier" <maz@kernel.org>, "Arnd Bergmann" <arnd@kernel.org>
Cc:     "Oliver Upton" <oliver.upton@linux.dev>,
        "Catalin Marinas" <catalin.marinas@arm.com>,
        "Will Deacon" <will@kernel.org>,
        "Shaoqin Huang" <shahuang@redhat.com>,
        "Ricardo Koller" <ricarkol@google.com>,
        "Gavin Shan" <gshan@redhat.com>,
        "James Morse" <james.morse@arm.com>,
        "Suzuki K Poulose" <suzuki.poulose@arm.com>,
        "Zenghui Yu" <yuzenghui@huawei.com>,
        "Cornelia Huck" <cohuck@redhat.com>,
        linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm64: kvm: avoid overflow in integer division
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On Thu, May 18, 2023, at 09:30, Marc Zyngier wrote:
> On Wed, 17 May 2023 21:23:39 +0100,
> Arnd Bergmann <arnd@kernel.org> wrote:
>> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
>> index 3386bd28d267..6db9ef288ec3 100644
>> --- a/arch/arm64/kvm/mmu.c
>> +++ b/arch/arm64/kvm/mmu.c
>> @@ -92,8 +92,8 @@ static int kvm_mmu_split_nr_page_tables(u64 range)
>>  	int n = 0;
>>  
>>  	if (KVM_PGTABLE_MIN_BLOCK_LEVEL < 2)
>> -		n += DIV_ROUND_UP_ULL(range, PUD_SIZE);
>> -	n += DIV_ROUND_UP_ULL(range, PMD_SIZE);
>> +		n += DIV_ROUND_UP(range, PUD_SIZE);
>> +	n += DIV_ROUND_UP(range, PMD_SIZE);
>>  	return n;
>>  }
>
> This is against -next, right? Oliver, I assume you'll take this as a
> fix for Ricardo's series?

Yes, correct, I saw it after rebasing my tree from 6.4-rc2 to the
latest -next.

     Arnd