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Date:   Wed, 12 May 2021 10:50:41 +0200
From:   'Joerg Roedel' <joro@8bytes.org>
To:     Juergen Gross <jgross@suse.com>
Cc:     David Laight <David.Laight@aculab.com>,
        "x86@kernel.org" <x86@kernel.org>,
        Hyunwook Baek <baekhw@google.com>,
        Joerg Roedel <jroedel@suse.de>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "hpa@zytor.com" <hpa@zytor.com>, Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Jiri Slaby <jslaby@suse.cz>,
        Dan Williams <dan.j.williams@intel.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Kees Cook <keescook@chromium.org>,
        David Rientjes <rientjes@google.com>,
        Cfir Cohen <cfir@google.com>,
        Erdem Aktas <erdemaktas@google.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Mike Stunes <mstunes@vmware.com>,
        Sean Christopherson <seanjc@google.com>,
        Martin Radev <martin.b.radev@gmail.com>,
        Arvind Sankar <nivedita@alum.mit.edu>,
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        "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        "virtualization@lists.linux-foundation.org" 
        <virtualization@lists.linux-foundation.org>
Subject: Re: [PATCH 3/6] x86/sev-es: Use __put_user()/__get_user
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On Wed, May 12, 2021 at 10:16:12AM +0200, Juergen Gross wrote:
> You want something like xen_safe_[read|write]_ulong().

From a first glance I can't see it, what is the difference between the
xen_safe_*_ulong() functions and __get_user()/__put_user()? The only
difference I can see is that __get/__put_user() support different access
sizes, but neither of those disables page-faults by itself, for example.

Couldn't these xen-specific functions not also be replaces by
__get_user()/__put_user()?

Regards,

	Joerg