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Subject: Re: [PATCH 01/17] x86: spec_ctrl: fix SPEC_CTRL initialization after
 kexec
To:     Andrea Arcangeli <aarcange@redhat.com>
Cc:     Vitaly Kuznetsov <vkuznets@redhat.com>,
        "Dr. David Alan Gilbert" <dgilbert@redhat.com>,
        Marcelo Tosatti <mtosatti@redhat.com>,
        Peter Xu <peterx@redhat.com>, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20190920212509.2578-1-aarcange@redhat.com>
 <20190920212509.2578-2-aarcange@redhat.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
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Date:   Mon, 23 Sep 2019 12:22:23 +0200
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On 20/09/19 23:24, Andrea Arcangeli wrote:
> We can't assume the SPEC_CTRL msr is zero at boot because it could be
> left enabled by a previous kernel booted with
> spec_store_bypass_disable=on.
> 
> Without this fix a boot with spec_store_bypass_disable=on followed by
> a kexec boot with spec_store_bypass_disable=off would erroneously and
> unexpectedly leave bit 2 set in SPEC_CTRL.
> 
> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>

Can you send this out separately, so that Thomas et al. can pick it up
as a bug fix?

Thanks,

Paolo