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Message-ID: <6b84f9058ce5e60fdf3e4abd075a2b8f591ccffc.camel@intel.com>
Subject: Re: [PATCH v8 4/5] x86/mm: Add noalias variants of
 set_memory_*crypted() functions
From:   Kai Huang <kai.huang@intel.com>
To:     Dave Hansen <dave.hansen@intel.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc:     Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H . Peter Anvin" <hpa@zytor.com>, Tony Luck <tony.luck@intel.com>,
        Andi Kleen <ak@linux.intel.com>,
        Wander Lairson Costa <wander@redhat.com>,
        Isaku Yamahata <isaku.yamahata@gmail.com>,
        marcelo.cerri@canonical.com, tim.gardner@canonical.com,
        khalid.elmously@canonical.com, philip.cox@canonical.com,
        linux-kernel@vger.kernel.org
Date:   Tue, 28 Jun 2022 13:15:21 +1200
In-Reply-To: <fe896ec7-cfce-e8ce-240d-88cca47f8996@intel.com>
References: <20220609025220.2615197-1-sathyanarayanan.kuppuswamy@linux.intel.com>
         <20220609025220.2615197-5-sathyanarayanan.kuppuswamy@linux.intel.com>
         <b4190b5d-89e8-b02f-5ef6-c05047af8166@intel.com>
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         <fe896ec7-cfce-e8ce-240d-88cca47f8996@intel.com>
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>=20
> I still don't like the idea of using the DMA API itself.  But, maybe we
> need some common infrastructure that the DMA API and this code use which
> says, "get me some pages that I can safely make shared".

Right.  For instance any KVM PV feature would require shared memory, and DM=
A API
normally doesn't fit (taking 'struct kvm_steal_time' as example).

Maybe we can reserve a CMA for this purpose.

--=20
Thanks,
-Kai