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From: Sean Christopherson <seanjc@google.com>
To: "Maciej S. Szmigiero" <mail@maciej.szmigiero.name>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	Igor Mammedov <imammedo@redhat.com>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] KVM: x86: Avoid overflowing nr_mmu_pages in kvm_arch_commit_memory_region()
Date: Mon, 29 Nov 2021 21:03:41 +0000	[thread overview]
Message-ID: <YaVALTZbutlVPz8k@google.com> (raw)
In-Reply-To: <44edcde46d12c2f5376a1cd1429650acb506ebaf.1637884349.git.maciej.szmigiero@oracle.com>

On Fri, Nov 26, 2021, Maciej S. Szmigiero wrote:
> From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com>
> 
> With kvm->nr_memslot_pages capped at ULONG_MAX we can't safely multiply it
> by KVM_PERMILLE_MMU_PAGES (20) since this operation can possibly overflow
> an unsigned long variable.
> 
> Rewrite this "* 20 / 1000" operation as "/ 50" instead to avoid such
> overflow.
> 
> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
> ---

Reviewed-by: Sean Christopherson <seanjc@google.com>

  reply	other threads:[~2021-11-29 22:44 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-26  0:31 [PATCH 0/3] KVM: Scalable memslots implementation additional patches Maciej S. Szmigiero
2021-11-26  0:31 ` [PATCH 1/3] KVM: x86: Avoid overflowing nr_mmu_pages in kvm_arch_commit_memory_region() Maciej S. Szmigiero
2021-11-29 21:03   ` Sean Christopherson [this message]
2021-11-26  0:31 ` [PATCH 2/3] KVM: Use atomic_long_cmpxchg() instead of an open-coded variant Maciej S. Szmigiero
2021-11-26 10:34   ` Paolo Bonzini
2021-11-26  0:31 ` [PATCH 3/3] KVM: Make kvm_for_each_memslot_in_gfn_range() strict and use iterators Maciej S. Szmigiero
2021-11-26 10:35 ` [PATCH 0/3] KVM: Scalable memslots implementation additional patches Paolo Bonzini
2021-11-26 13:18   ` Maciej S. Szmigiero
2021-11-26 13:19     ` Paolo Bonzini

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