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Message-ID: <a610ae9bd554f31364193abc928fad86ed5ebf7c.camel@intel.com>
Subject: Re: [PATCH v5 15/22] x86/virt/tdx: Allocate and set up PAMTs for
 TDMRs
From:   Kai Huang <kai.huang@intel.com>
To:     Dave Hansen <dave.hansen@intel.com>, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org
Cc:     seanjc@google.com, pbonzini@redhat.com, len.brown@intel.com,
        tony.luck@intel.com, rafael.j.wysocki@intel.com,
        reinette.chatre@intel.com, dan.j.williams@intel.com,
        peterz@infradead.org, ak@linux.intel.com,
        kirill.shutemov@linux.intel.com,
        sathyanarayanan.kuppuswamy@linux.intel.com,
        isaku.yamahata@intel.com
Date:   Tue, 28 Jun 2022 10:50:36 +1200
In-Reply-To: <b43bf089-1202-a1fe-cbb3-d4e0926cab67@intel.com>
References: <cover.1655894131.git.kai.huang@intel.com>
         <c504a8acd06dc455050c25e2a4cc70aef5eb9358.1655894131.git.kai.huang@intel.com>
         <e72703b0-767a-ec88-7cb6-f95a3564d823@intel.com>
         <b376aef05bc032fdf8cc23762ce77a14830440cd.camel@intel.com>
         <b43bf089-1202-a1fe-cbb3-d4e0926cab67@intel.com>
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On Mon, 2022-06-27 at 13:41 -0700, Dave Hansen wrote:
> On 6/27/22 03:31, Kai Huang wrote:
> > > > +/* Page sizes supported by TDX */
> > > > +enum tdx_page_sz {
> > > > +	TDX_PG_4K,
> > > > +	TDX_PG_2M,
> > > > +	TDX_PG_1G,
> > > > +	TDX_PG_MAX,
> > > > +};
> > > Are these the same constants as the magic numbers in Kirill's
> > > try_accept_one()?
> > try_accept_once() uses 'enum pg_level' PG_LEVEL_{4K,2M,1G} directly.  T=
hey can
> > be used directly too, but 'enum pg_level' has more than we need here:
>=20
> I meant this:
>=20
> +       switch (level) {
> +       case PG_LEVEL_4K:
> +               page_size =3D 0;
> +               break;
>=20
> Because TDX_PG_4K=3D=3Dpage_size=3D=3D0, and for this:
>=20
> +       case PG_LEVEL_2M:
> +               page_size =3D 1;
>=20
> where TDX_PG_2M=3D=3Dpage_size=3D=3D1
>=20
> See?
>=20
> Are Kirill's magic 0/1/2 numbers the same as
>=20
> 	TDX_PG_4K,
> 	TDX_PG_2M,
> 	TDX_PG_1G,
>=20
> ?

Yes they are the same.  Kirill uses 0/1/2 as input of TDX_ACCEPT_PAGE TDCAL=
L.=20
Here I only need them to distinguish different page sizes.

Do you mean we should put TDX_PG_4K/2M/1G definition to asm/tdx.h, and
try_accept_one() should use them instead of magic 0/1/2?


--=20
Thanks,
-Kai