From: Christoph Hellwig <hch@infradead.org>
To: Sean Christopherson <seanjc@google.com>
Cc: Christoph Hellwig <hch@infradead.org>,
David Stevens <stevensd@chromium.org>,
Yu Zhang <yu.c.zhang@linux.intel.com>,
Isaku Yamahata <isaku.yamahata@gmail.com>,
Zhi Wang <zhi.wang.linux@gmail.com>,
kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org
Subject: Re: [PATCH v9 0/6] KVM: allow mapping non-refcounted pages
Date: Sun, 1 Oct 2023 23:25:34 -0700 [thread overview]
Message-ID: <ZRpiXsm7X6BFAU/y@infradead.org> (raw)
In-Reply-To: <ZRb2CljPvHlUErwM@google.com>
On Fri, Sep 29, 2023 at 09:06:34AM -0700, Sean Christopherson wrote:
> KVM needs to be aware of non-refcounted struct page memory no matter what; see
> CVE-2021-22543 and, commit f8be156be163 ("KVM: do not allow mapping valid but
> non-reference-counted pages"). I don't think it makes any sense whatsoever to
> remove that code and assume every driver in existence will do the right thing.
Agreed.
>
> With the cleanups done, playing nice with non-refcounted paged instead of outright
> rejecting them is a wash in terms of lines of code, complexity, and ongoing
> maintenance cost.
I tend to strongly disagree with that, though. We can't just let these
non-refcounted pages spread everywhere and instead need to fix their
usage.
next prev parent reply other threads:[~2023-10-02 6:25 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-11 2:16 David Stevens
2023-09-11 2:16 ` [PATCH v9 1/6] KVM: Assert that a page's refcount is elevated when marking accessed/dirty David Stevens
2023-09-11 2:16 ` [PATCH v9 2/6] KVM: mmu: Introduce __kvm_follow_pfn function David Stevens
2023-10-03 16:54 ` Maxim Levitsky
2024-02-06 1:25 ` Sean Christopherson
2024-02-06 3:16 ` Sean Christopherson
2024-02-13 3:27 ` Sean Christopherson
2024-02-13 3:44 ` Sean Christopherson
2023-09-11 2:16 ` [PATCH v9 3/6] KVM: mmu: Improve handling of non-refcounted pfns David Stevens
2023-10-03 16:54 ` Maxim Levitsky
2024-02-06 2:54 ` Sean Christopherson
2024-02-13 3:44 ` Sean Christopherson
2023-09-11 2:16 ` [PATCH v9 4/6] KVM: Migrate kvm_vcpu_map to __kvm_follow_pfn David Stevens
2023-10-03 16:54 ` Maxim Levitsky
2023-09-11 2:16 ` [PATCH v9 5/6] KVM: x86: Migrate " David Stevens
2023-10-03 16:54 ` Maxim Levitsky
2023-10-03 20:58 ` Sean Christopherson
2023-09-11 2:16 ` [PATCH v9 6/6] KVM: x86/mmu: Handle non-refcounted pages David Stevens
2023-09-18 9:53 ` Dmitry Osipenko
2023-09-19 2:25 ` David Stevens
2023-09-30 13:34 ` Dmitry Osipenko
2023-09-18 9:58 ` Dmitry Osipenko
2023-09-18 11:19 ` Dmitry Osipenko
2023-09-19 2:59 ` David Stevens
2023-09-21 20:06 ` Dmitry Osipenko
2023-09-30 13:34 ` Dmitry Osipenko
2023-09-19 2:31 ` David Stevens
2023-09-21 20:04 ` Dmitry Osipenko
2024-02-06 3:02 ` Sean Christopherson
2023-10-03 16:54 ` Maxim Levitsky
2024-02-06 3:23 ` Sean Christopherson
2023-09-29 5:19 ` [PATCH v9 0/6] KVM: allow mapping " Christoph Hellwig
2023-09-29 16:06 ` Sean Christopherson
2023-10-02 6:25 ` Christoph Hellwig [this message]
2024-02-06 3:29 ` Sean Christopherson
2023-10-31 4:30 ` David Stevens
2023-10-31 14:30 ` Sean Christopherson
2023-12-12 1:59 ` David Stevens
2023-12-20 1:37 ` Sean Christopherson
2024-02-06 3:30 ` Sean Christopherson
2024-02-13 3:39 ` Sean Christopherson
2024-02-21 6:05 ` David Stevens
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