linux-kernel - Re: [PATCH v3 00/21] TDX host kernel support

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: <1b681365-ef98-ec78-96dc-04e28316cf0e@intel.com>
Date:   Tue, 3 May 2022 17:25:35 -0700
From:   Dave Hansen <dave.hansen@...el.com>
To:     Kai Huang <kai.huang@...el.com>, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Cc:     seanjc@...gle.com, pbonzini@...hat.com, len.brown@...el.com,
        tony.luck@...el.com, rafael.j.wysocki@...el.com,
        reinette.chatre@...el.com, dan.j.williams@...el.com,
        peterz@...radead.org, ak@...ux.intel.com,
        kirill.shutemov@...ux.intel.com,
        sathyanarayanan.kuppuswamy@...ux.intel.com,
        isaku.yamahata@...el.com
Subject: Re: [PATCH v3 00/21] TDX host kernel support

On 5/3/22 16:59, Kai Huang wrote:
> Should be:
> 
> 	// prevent racing with TDX module initialization */
> 	tdx_init_disable();
> 
> 	if (tdx_module_initialized()) {
> 		if (new_memory_resource in TDMRs)
> 			// allow memory hot-add
> 		else
> 			// reject memory hot-add
> 	} else if (new_memory_resource in CMR) {
> 		// add new memory to TDX memory so it can be
> 		// included into TDMRs
> 
> 		// allow memory hot-add
> 	}
> 	else
> 		// reject memory hot-add
> 	
> 	tdx_module_enable();
> 
> And when platform doesn't TDX, always allow memory hot-add.

I don't think it even needs to be *that* complicated.

It could just be winner take all: if TDX is initialized first, don't
allow memory hotplug.  If memory hotplug happens first, don't allow TDX
to be initialized.

That's fine at least for a minimal patch set.

What you have up above is probably where you want to go eventually, but
it means doing things like augmenting the e820 since it's the single
source of truth for creating the TMDRs right now.