netdev - RE: [PATCH v5 06/14] x86/ioremap: Support hypervisor specified range to map as encrypted

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <BYAPR21MB16880EC9C85EC9343F9AF178D7A19@BYAPR21MB1688.namprd21.prod.outlook.com>
Date:   Fri, 17 Feb 2023 06:16:56 +0000
From:   "Michael Kelley (LINUX)" <mikelley@...rosoft.com>
To:     Borislav Petkov <bp@...en8.de>
CC:     Sean Christopherson <seanjc@...gle.com>,
        Dave Hansen <dave.hansen@...el.com>,
        "hpa@...or.com" <hpa@...or.com>, KY Srinivasan <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        "wei.liu@...nel.org" <wei.liu@...nel.org>,
        Dexuan Cui <decui@...rosoft.com>,
        "luto@...nel.org" <luto@...nel.org>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "edumazet@...gle.com" <edumazet@...gle.com>,
        "kuba@...nel.org" <kuba@...nel.org>,
        "pabeni@...hat.com" <pabeni@...hat.com>,
        "lpieralisi@...nel.org" <lpieralisi@...nel.org>,
        "robh@...nel.org" <robh@...nel.org>, "kw@...ux.com" <kw@...ux.com>,
        "bhelgaas@...gle.com" <bhelgaas@...gle.com>,
        "arnd@...db.de" <arnd@...db.de>, "hch@....de" <hch@....de>,
        "m.szyprowski@...sung.com" <m.szyprowski@...sung.com>,
        "robin.murphy@....com" <robin.murphy@....com>,
        "thomas.lendacky@....com" <thomas.lendacky@....com>,
        "brijesh.singh@....com" <brijesh.singh@....com>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
        Tianyu Lan <Tianyu.Lan@...rosoft.com>,
        "kirill.shutemov@...ux.intel.com" <kirill.shutemov@...ux.intel.com>,
        "sathyanarayanan.kuppuswamy@...ux.intel.com" 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>,
        "ak@...ux.intel.com" <ak@...ux.intel.com>,
        "isaku.yamahata@...el.com" <isaku.yamahata@...el.com>,
        "dan.j.williams@...el.com" <dan.j.williams@...el.com>,
        "jane.chu@...cle.com" <jane.chu@...cle.com>,
        "tony.luck@...el.com" <tony.luck@...el.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-hyperv@...r.kernel.org" <linux-hyperv@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>,
        "iommu@...ts.linux.dev" <iommu@...ts.linux.dev>
Subject: RE: [PATCH v5 06/14] x86/ioremap: Support hypervisor specified range
 to map as encrypted



From: Borislav Petkov <bp@...en8.de> Sent: Thursday, February 16, 2023 9:07 AM
> 
> ... here.
> 
> We need a single way to test for this guest type and stick with it.
> 
> I'd like for all guest types we support to be queried in a plain and
> simple way.
> 
> Not:
> 
> * CC_ATTR_GUEST_MEM_ENCRYPT
> 
> * x86_platform.hyper.is_private_mmio(addr)
> 
> * CC_ATTR_PARAVISOR
> 
> to mean three different aspects of SEV-SNP guests using vTOM on Hyper-V.
> 
> This is going to be a major mess which we won't support.
> 

OK, I'm trying to figure out where to go next.  I've been following the pattern
set by the SEV/SEV-ES/SEV-SNP and TDX platforms in the cc_platform_has()
function.   Each platform returns "true" for multiple CC_ATTR_* values,
and those CC_ATTR_* values are tested in multiple places throughout
kernel code.  Some CC_ATTR_* values are shared by multiple platforms
(like CC_ATTR_GUEST_MEM_ENCRYPT) and some are unique to a particular
platform (like CC_ATTR_HOTPLUG_DISABLED).  For the CC_ATTR_* values
that are shared, the logic of which platforms they apply to occurs once in
cc_platform_has() rather than scattered and duplicated throughout the
kernel, which makes sense.  Any given platform is not represented by a
single CC_ATTR_* value, but by multiple ones.  Each CC_ATTR_* value 
essentially represents a chunk of kernel functionality that one or more
platforms need, and the platform indicates its need by cc_platform_has()
returning "true" for that value.

So I've been trying to apply the same pattern to the SNP vTOM sub-case
of SEV-SNP.   Is that consistent with your thinking, or is the whole
cc_platform_has() approach problematic, including for the existing
SEV flavors and for TDX?

Michael