From: "Huang, Kai" <kai.huang@intel.com>
To: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"Hansen, Dave" <dave.hansen@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: "Luck, Tony" <tony.luck@intel.com>,
"bagasdotme@gmail.com" <bagasdotme@gmail.com>,
"ak@linux.intel.com" <ak@linux.intel.com>,
"Wysocki, Rafael J" <rafael.j.wysocki@intel.com>,
"kirill.shutemov@linux.intel.com"
<kirill.shutemov@linux.intel.com>, "Christopherson,,
Sean" <seanjc@google.com>,
"Chatre, Reinette" <reinette.chatre@intel.com>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"Yamahata, Isaku" <isaku.yamahata@intel.com>,
"Shahar, Sagi" <sagis@google.com>,
"imammedo@redhat.com" <imammedo@redhat.com>,
"Gao, Chao" <chao.gao@intel.com>,
"Brown, Len" <len.brown@intel.com>,
"peterz@infradead.org" <peterz@infradead.org>,
"sathyanarayanan.kuppuswamy@linux.intel.com"
<sathyanarayanan.kuppuswamy@linux.intel.com>,
"Huang, Ying" <ying.huang@intel.com>,
"Williams, Dan J" <dan.j.williams@intel.com>
Subject: Re: [PATCH v7 02/20] x86/virt/tdx: Detect TDX during kernel boot
Date: Tue, 22 Nov 2022 23:21:41 +0000 [thread overview]
Message-ID: <b6f505bec9984febab84964c6422b4195938ff62.camel@intel.com> (raw)
In-Reply-To: <f743a4df-f285-3f07-02ef-b908020e0c93@intel.com>
On Tue, 2022-11-22 at 08:50 -0800, Dave Hansen wrote:
> On 11/22/22 03:28, Huang, Kai wrote:
> > > > + /*
> > > > + * KeyID 0 is for TME. MKTME KeyIDs start from 1. TDX private
> > > > + * KeyIDs start after the last MKTME KeyID.
> > > > + */
> > >
> > > Is the TME key a "MKTME KeyID"?
> >
> > I don't think so. Hardware handles TME KeyID 0 differently from non-0 MKTME
> > KeyIDs. And PCONFIG only accept non-0 KeyIDs.
>
> Let's say we have 4 MKTME hardware bits, we'd have:
>
> 0: TME Key
> 1->3: MKTME Keys
> 4->7: TDX Private Keys
>
> First, the MSR values:
>
> > + * IA32_MKTME_KEYID_PARTIONING:
> > + * Bit [31:0]: Number of MKTME KeyIDs.
> > + * Bit [63:32]: Number of TDX private KeyIDs.
>
> These would be:
>
> Bit [ 31:0] = 3
> Bit [63:22] = 4
>
> And in the end the variables:
>
> tdx_keyid_start would be 4 and tdx_keyid_num would be 4.
>
> Right?
Yes.
>
> That's a bit wonky for my brain because I guess I know too much about
> the internal implementation and how the key space is split up. I guess
> I (wrongly) expected Bit[31:0]==Bit[63:22].
The spec says the The Bit[31:0] only reports the number of MKTME KeyIDs, and it
does exclude KeyID 0.
My machine has 6 hardware bits in total (that is KeyID 0 ~ 63), and the upper 48
KeyIDs are reserved to TDX. In my case:
[Bit 31:0] = 15
[Bit 63:32] = 48
And tdx_keyid_start and nr_tdx_keyids are 16 and 48.
The TDX KeyID range: [16, 63], or [16, 64).
So [Bit 31:0] reports only "NUM_MKTME_KIDS", which excludes KeyID 0.
>
>
>
> > > > +static void __init clear_tdx(void)
> > > > +{
> > > > + tdx_keyid_start = tdx_keyid_num = 0;
> > > > +}
> > >
> > > This is where a comment is needed and can actually help.
> > >
> > > /*
> > > * tdx_keyid_start/num indicate that TDX is uninitialized. This
> > > * is used in TDX initialization error paths to take it from
> > > * initialized -> uninitialized.
> > > */
> >
> > Just want to point out after removing the !x2apic_enabled() check, the only
> > thing need to do here is to detect/record the TDX KeyIDs.
> >
> > And the purpose of this TDX boot-time initialization code is to provide
> > platform_tdx_enabled() function so that kexec() can use.
> >
> > To distinguish boot-time TDX initialization from runtime TDX module
> > initialization, how about change the comment to below?
> >
> > static void __init clear_tdx(void)
> > {
> > /*
> > * tdx_keyid_start and nr_tdx_keyids indicate that TDX is not
> > * enabled by the BIOS. This is used in TDX boot-time
> > * initializatiton error paths to take it from enabled to not
> > * enabled.
> > */
> > tdx_keyid_start = nr_tdx_keyids = 0;
> > }
> >
> > [...]
>
> I honestly have no idea what "boot-time TDX initialization" is versus
> "runtime TDX module initialization". This doesn't hel.
I'll use your original comment.
>
> > And below is the updated patch. How does it look to you?
>
> Let's see...
>
> ...
> > +static u32 tdx_keyid_start __ro_after_init;
> > +static u32 nr_tdx_keyids __ro_after_init;
> > +
> > +static int __init record_keyid_partitioning(void)
> > +{
> > + u32 nr_mktme_keyids;
> > + int ret;
> > +
> > + /*
> > + * IA32_MKTME_KEYID_PARTIONING:
> > + * Bit [31:0]: Number of MKTME KeyIDs.
> > + * Bit [63:32]: Number of TDX private KeyIDs.
> > + */
> > + ret = rdmsr_safe(MSR_IA32_MKTME_KEYID_PARTITIONING, &nr_mktme_keyids,
> > + &nr_tdx_keyids);
> > + if (ret)
> > + return -ENODEV;
> > +
> > + if (!nr_tdx_keyids)
> > + return -ENODEV;
> > +
> > + /* TDX KeyIDs start after the last MKTME KeyID. */
> > + tdx_keyid_start++;
>
> tdx_keyid_start is uniniitalized here. So, it'd be 0, then ++'d.
>
> Kai, please take a moment and slow down. This isn't a race. I offered
> some replacement code here, which you've discarded, missed or ignored
> and in the process broken this code.
>
> This approach just wastes reviewer time. It's not working for me.
Apology. I missed it this time.
>
> I'm going to make a suggestion (aka. a demand): You can post these
> patches at most once a week. You get a whole week to (carefully)
> incorporate reviewer feedback, make the patch better, and post a new
> version. Need more time? Go ahead and take it. Take as much time as
> you want.
>
Yes will follow.
next prev parent reply other threads:[~2022-11-22 23:21 UTC|newest]
Thread overview: 163+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-21 0:26 [PATCH v7 00/20] TDX host kernel support Kai Huang
2022-11-21 0:26 ` [PATCH v7 01/20] x86/tdx: Define TDX supported page sizes as macros Kai Huang
2022-11-21 2:52 ` Sathyanarayanan Kuppuswamy
2022-11-21 9:15 ` Huang, Kai
2022-11-21 17:23 ` Sathyanarayanan Kuppuswamy
2022-11-21 18:12 ` Dave Hansen
2022-11-21 23:48 ` Dave Hansen
2022-11-22 0:01 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 02/20] x86/virt/tdx: Detect TDX during kernel boot Kai Huang
2022-11-21 3:07 ` Sathyanarayanan Kuppuswamy
2022-11-21 9:37 ` Huang, Kai
2022-11-21 23:57 ` Sathyanarayanan Kuppuswamy
2022-11-22 0:10 ` Dave Hansen
2022-11-22 11:28 ` Huang, Kai
2022-11-22 16:50 ` Dave Hansen
2022-11-22 23:21 ` Huang, Kai [this message]
2022-11-21 0:26 ` [PATCH v7 03/20] x86/virt/tdx: Disable TDX if X2APIC is not enabled Kai Huang
2022-11-21 3:51 ` Sathyanarayanan Kuppuswamy
2022-11-21 9:44 ` Huang, Kai
2022-11-21 22:00 ` Sathyanarayanan Kuppuswamy
2022-11-21 23:40 ` Huang, Kai
2022-11-21 23:46 ` Dave Hansen
2022-11-22 0:30 ` Huang, Kai
2022-11-22 0:44 ` Dave Hansen
2022-11-22 0:58 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 04/20] x86/virt/tdx: Add skeleton to initialize TDX on demand Kai Huang
2022-11-22 9:02 ` Peter Zijlstra
2022-11-22 10:31 ` Thomas Gleixner
2022-11-22 15:35 ` Dave Hansen
2022-11-22 20:03 ` Thomas Gleixner
2022-11-22 20:11 ` Sean Christopherson
2022-11-23 0:30 ` Huang, Kai
2022-11-23 1:12 ` Huang, Kai
2022-11-23 11:05 ` Thomas Gleixner
2022-11-23 12:22 ` Huang, Kai
2022-11-22 18:05 ` Dave Hansen
2022-11-23 10:18 ` Huang, Kai
2022-11-23 16:58 ` Dave Hansen
2022-11-23 21:58 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 05/20] x86/virt/tdx: Implement functions to make SEAMCALL Kai Huang
2022-11-22 9:06 ` Peter Zijlstra
2022-11-23 8:53 ` Huang, Kai
2022-11-22 18:20 ` Dave Hansen
2022-11-23 10:43 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 06/20] x86/virt/tdx: Shut down TDX module in case of error Kai Huang
2022-11-22 9:10 ` Peter Zijlstra
2022-11-22 9:13 ` Peter Zijlstra
2022-11-22 15:14 ` Dave Hansen
2022-11-22 19:13 ` Peter Zijlstra
2022-11-22 19:24 ` Dave Hansen
2022-11-22 19:33 ` Peter Zijlstra
2022-11-23 1:14 ` Huang, Kai
2022-11-29 21:40 ` Dave Hansen
2022-11-30 11:09 ` Thomas Gleixner
2022-11-23 0:58 ` Huang, Kai
2022-11-23 1:04 ` Dave Hansen
2022-11-23 1:22 ` Huang, Kai
2022-11-23 16:20 ` Sean Christopherson
2022-11-23 16:41 ` Dave Hansen
2022-11-23 17:37 ` Sean Christopherson
2022-11-23 18:18 ` Dave Hansen
2022-11-23 19:03 ` Sean Christopherson
2022-11-22 9:20 ` Peter Zijlstra
2022-11-22 15:06 ` Thomas Gleixner
2022-11-22 19:06 ` Peter Zijlstra
2022-11-22 19:31 ` Sean Christopherson
2022-11-23 9:39 ` Huang, Kai
2022-11-22 15:20 ` Dave Hansen
2022-11-22 16:52 ` Thomas Gleixner
2022-11-22 18:57 ` Dave Hansen
2022-11-22 19:14 ` Peter Zijlstra
2022-11-23 1:24 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 07/20] x86/virt/tdx: Do TDX module global initialization Kai Huang
2022-11-22 19:14 ` Dave Hansen
2022-11-23 11:45 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 08/20] x86/virt/tdx: Do logical-cpu scope TDX module initialization Kai Huang
2022-11-21 0:26 ` [PATCH v7 09/20] x86/virt/tdx: Get information about TDX module and TDX-capable memory Kai Huang
2022-11-22 23:39 ` Dave Hansen
2022-11-23 11:40 ` Huang, Kai
2022-11-23 16:44 ` Dave Hansen
2022-11-23 22:53 ` Huang, Kai
2022-12-02 11:19 ` Huang, Kai
2022-12-02 17:25 ` Dave Hansen
2022-12-02 21:57 ` Huang, Kai
2022-12-02 11:11 ` Huang, Kai
2022-12-02 17:06 ` Dave Hansen
2022-12-02 21:56 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 10/20] x86/virt/tdx: Use all system memory when initializing TDX module as TDX memory Kai Huang
2022-11-21 5:37 ` Huang, Ying
2022-11-21 9:09 ` Huang, Kai
2022-11-22 1:54 ` Huang, Ying
2022-11-22 9:16 ` Huang, Kai
2022-11-24 0:47 ` Huang, Ying
2022-11-22 10:10 ` Peter Zijlstra
2022-11-22 11:40 ` Huang, Kai
2022-11-23 0:21 ` Dave Hansen
2022-11-23 9:29 ` Peter Zijlstra
2022-11-24 1:04 ` Huang, Kai
2022-11-24 1:22 ` Dave Hansen
2022-11-24 2:27 ` Huang, Kai
2022-11-24 1:50 ` Dan Williams
2022-11-24 9:06 ` Huang, Kai
2022-11-25 9:28 ` David Hildenbrand
2022-11-28 8:38 ` Huang, Kai
2022-11-28 8:43 ` David Hildenbrand
2022-11-28 9:21 ` Huang, Kai
2022-11-28 9:26 ` David Hildenbrand
2022-11-28 9:50 ` Huang, Kai
2022-11-24 9:26 ` Peter Zijlstra
2022-11-24 10:02 ` Huang, Kai
2022-11-30 22:26 ` Dave Hansen
2022-11-21 0:26 ` [PATCH v7 11/20] x86/virt/tdx: Add placeholder to construct TDMRs to cover all TDX memory regions Kai Huang
2022-11-23 22:17 ` Dave Hansen
2022-11-24 9:51 ` Huang, Kai
2022-11-24 12:02 ` Huang, Kai
2022-11-28 15:59 ` Dave Hansen
2022-11-28 22:13 ` Huang, Kai
2022-11-28 22:19 ` Dave Hansen
2022-11-28 22:50 ` Huang, Kai
2022-12-07 11:47 ` Huang, Kai
2022-12-08 12:56 ` Huang, Kai
2022-12-08 14:58 ` Dave Hansen
2022-12-08 23:29 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 12/20] x86/virt/tdx: Create " Kai Huang
2022-11-23 22:41 ` Dave Hansen
2022-11-24 11:29 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 13/20] x86/virt/tdx: Allocate and set up PAMTs for TDMRs Kai Huang
2022-11-23 22:57 ` Dave Hansen
2022-11-24 11:46 ` Huang, Kai
2022-11-28 16:39 ` Dave Hansen
2022-11-28 22:48 ` Huang, Kai
2022-11-28 22:56 ` Dave Hansen
2022-11-28 23:14 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 14/20] x86/virt/tdx: Set up reserved areas for all TDMRs Kai Huang
2022-11-23 23:39 ` Dave Hansen
2022-11-28 9:14 ` Huang, Kai
2022-11-28 13:18 ` Dave Hansen
2022-11-28 22:24 ` Huang, Kai
2022-11-28 22:58 ` Dave Hansen
2022-11-28 23:10 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 15/20] x86/virt/tdx: Reserve TDX module global KeyID Kai Huang
2022-11-23 23:40 ` Dave Hansen
2022-11-24 22:39 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 16/20] x86/virt/tdx: Configure TDX module with TDMRs and " Kai Huang
2022-11-23 23:56 ` Dave Hansen
2022-11-25 0:59 ` Huang, Kai
2022-11-25 1:18 ` Dave Hansen
2022-11-25 1:44 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 17/20] x86/virt/tdx: Configure global KeyID on all packages Kai Huang
2022-11-24 0:28 ` Dave Hansen
2022-11-24 22:28 ` Huang, Kai
2022-11-25 0:08 ` Huang, Kai
2022-11-30 3:35 ` Binbin Wu
2022-11-30 8:34 ` Huang, Kai
2022-11-30 14:04 ` kirill.shutemov
2022-11-30 15:13 ` Dave Hansen
2022-11-30 20:17 ` Huang, Kai
2022-11-30 17:37 ` Dave Hansen
2022-11-21 0:26 ` [PATCH v7 18/20] x86/virt/tdx: Initialize all TDMRs Kai Huang
2022-11-24 0:42 ` Dave Hansen
2022-11-25 2:27 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 19/20] x86/virt/tdx: Flush cache in kexec() when TDX is enabled Kai Huang
2022-11-21 0:26 ` [PATCH v7 20/20] Documentation/x86: Add documentation for TDX host support Kai Huang
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