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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sat, 30 May 2020 12:20:54 -0700
Message-ID: <CAHk-=wg03AwbLH0zLRbOOQR_cZD89dM0KMU-uLMkG2sG9K_yag@mail.gmail.com>
Subject: Re: [PATCH 8/9] x86: kvm_hv_set_msr(): use __put_user() instead of
 32bit __clear_user()
To:     Al Viro <viro@zeniv.linux.org.uk>
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        KVM list <kvm@vger.kernel.org>
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On Sat, May 30, 2020 at 12:14 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> > And none of that code verifies that the end result is a user address.
>
> kvm_is_error_hva() is
>         return addr >= PAGE_OFFSET;

Ahh, that's what I missed. It won't work on other architectures, but
within x86 it's fine.

                  Linus