From: Dave Hansen <dave.hansen@intel.com>
To: Kai Huang <kai.huang@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
Subject: Re: [PATCH v3 04/21] x86/virt/tdx: Add skeleton for detecting and initializing TDX on demand
Date: Thu, 28 Apr 2022 17:26:52 -0700 [thread overview]
Message-ID: <966b1f45-ba5d-febd-e365-29308a9a59b4@intel.com> (raw)
In-Reply-To: <af6fccf2f6f8d83593f0eedd003c7cd07f89274d.camel@intel.com>
On 4/28/22 17:11, Kai Huang wrote:
> This is true. So I think w/o taking the lock is also fine, as the TDX module
> initialization is a state machine. If any cpu goes offline during logical-cpu
> level initialization and TDH.SYS.LP.INIT isn't done on that cpu, then later the
> TDH.SYS.CONFIG will fail. Similarly, if any cpu going offline causes
> TDH.SYS.KEY.CONFIG is not done for any package, then TDH.SYS.TDMR.INIT will
> fail.
Right. The worst-case scenario is someone is mucking around with CPU
hotplug during TDX initialization is that TDX initialization will fail.
We *can* fix some of this at least and provide coherent error messages
with a pattern like this:
cpus_read_lock();
// check that all MADT-enumerated CPUs are online
tdx_init();
cpus_read_unlock();
That, of course, *does* prevent CPUs from going offline during
tdx_init(). It also provides a nice place for an error message:
pr_warn("You offlined a CPU then want to use TDX? Sod off.\n");
> A problem (I realized it exists in current implementation too) is shutting down
> the TDX module, which requires calling TDH.SYS.LP.SHUTDOWN on all BIOS-enabled
> cpus. Kernel can do this SEAMCALL at most for all present cpus. However when
> any cpu is offline, this SEAMCALL won't be called on it, and it seems we need to
> add new CPU hotplug callback to call this SEAMCALL when the cpu is online again.
Hold on a sec. If you call TDH.SYS.LP.SHUTDOWN on any CPU, then TDX
stops working everywhere, right? But, if someone offlines one CPU, we
don't want TDX to stop working everywhere.
next prev parent reply other threads:[~2022-04-29 0:26 UTC|newest]
Thread overview: 156+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-06 4:49 [PATCH v3 00/21] TDX host kernel support Kai Huang
2022-04-06 4:49 ` [PATCH v3 01/21] x86/virt/tdx: Detect SEAM Kai Huang
2022-04-18 22:29 ` Sathyanarayanan Kuppuswamy
2022-04-18 22:50 ` Sean Christopherson
2022-04-19 3:38 ` Kai Huang
2022-04-26 20:21 ` Dave Hansen
2022-04-26 23:12 ` Kai Huang
2022-04-26 23:28 ` Dave Hansen
2022-04-26 23:49 ` Kai Huang
2022-04-27 0:22 ` Sean Christopherson
2022-04-27 0:44 ` Kai Huang
2022-04-27 14:22 ` Dave Hansen
2022-04-27 22:39 ` Kai Huang
2022-04-06 4:49 ` [PATCH v3 02/21] x86/virt/tdx: Detect TDX private KeyIDs Kai Huang
2022-04-19 5:39 ` Sathyanarayanan Kuppuswamy
2022-04-19 9:41 ` Kai Huang
2022-04-19 5:42 ` Sathyanarayanan Kuppuswamy
2022-04-19 10:07 ` Kai Huang
2022-04-06 4:49 ` [PATCH v3 03/21] x86/virt/tdx: Implement the SEAMCALL base function Kai Huang
2022-04-19 14:07 ` Sathyanarayanan Kuppuswamy
2022-04-20 4:16 ` Kai Huang
2022-04-20 7:29 ` Sathyanarayanan Kuppuswamy
2022-04-20 10:39 ` Kai Huang
2022-04-26 20:37 ` Dave Hansen
2022-04-26 23:29 ` Kai Huang
2022-04-06 4:49 ` [PATCH v3 04/21] x86/virt/tdx: Add skeleton for detecting and initializing TDX on demand Kai Huang
2022-04-19 14:53 ` Sathyanarayanan Kuppuswamy
2022-04-20 4:37 ` Kai Huang
2022-04-20 5:21 ` Dave Hansen
2022-04-20 14:30 ` Sathyanarayanan Kuppuswamy
2022-04-20 22:35 ` Kai Huang
2022-04-26 20:53 ` Dave Hansen
2022-04-27 0:43 ` Kai Huang
2022-04-27 14:49 ` Dave Hansen
2022-04-28 0:00 ` Kai Huang
2022-04-28 14:27 ` Dave Hansen
2022-04-28 23:44 ` Kai Huang
2022-04-28 23:53 ` Dave Hansen
2022-04-29 0:11 ` Kai Huang
2022-04-29 0:26 ` Dave Hansen [this message]
2022-04-29 0:59 ` Kai Huang
2022-04-06 4:49 ` [PATCH v3 05/21] x86/virt/tdx: Detect P-SEAMLDR and TDX module Kai Huang
2022-04-26 20:56 ` Dave Hansen
2022-04-27 0:01 ` Kai Huang
2022-04-27 14:24 ` Dave Hansen
2022-04-27 21:30 ` Kai Huang
2022-04-06 4:49 ` [PATCH v3 06/21] x86/virt/tdx: Shut down TDX module in case of error Kai Huang
2022-04-23 15:39 ` Sathyanarayanan Kuppuswamy
2022-04-25 23:41 ` Kai Huang
2022-04-26 1:48 ` Sathyanarayanan Kuppuswamy
2022-04-26 2:12 ` Kai Huang
2022-04-26 20:59 ` Dave Hansen
2022-04-27 0:06 ` Kai Huang
2022-05-18 16:19 ` Sagi Shahar
2022-05-18 23:51 ` Kai Huang
2022-04-06 4:49 ` [PATCH v3 07/21] x86/virt/tdx: Do TDX module global initialization Kai Huang
2022-04-20 22:27 ` Sathyanarayanan Kuppuswamy
2022-04-20 22:37 ` Kai Huang
2022-04-06 4:49 ` [PATCH v3 08/21] x86/virt/tdx: Do logical-cpu scope TDX module initialization Kai Huang
2022-04-24 1:27 ` Sathyanarayanan Kuppuswamy
2022-04-25 23:55 ` Kai Huang
2022-04-06 4:49 ` [PATCH v3 09/21] x86/virt/tdx: Get information about TDX module and convertible memory Kai Huang
2022-04-25 2:58 ` Sathyanarayanan Kuppuswamy
2022-04-26 0:05 ` Kai Huang
2022-04-27 22:15 ` Dave Hansen
2022-04-28 0:15 ` Kai Huang
2022-04-28 14:06 ` Dave Hansen
2022-04-28 23:14 ` Kai Huang
2022-04-29 17:47 ` Dave Hansen
2022-05-02 5:04 ` Kai Huang
2022-05-25 4:47 ` Kai Huang
2022-05-25 4:57 ` Kai Huang
2022-05-25 16:00 ` Kai Huang
2022-05-18 22:30 ` Sagi Shahar
2022-05-18 23:56 ` Kai Huang
2022-04-06 4:49 ` [PATCH v3 10/21] x86/virt/tdx: Add placeholder to coveret all system RAM as TDX memory Kai Huang
2022-04-20 20:48 ` Isaku Yamahata
2022-04-20 22:38 ` Kai Huang
2022-04-27 22:24 ` Dave Hansen
2022-04-28 0:53 ` Kai Huang
2022-04-28 1:07 ` Dave Hansen
2022-04-28 1:35 ` Kai Huang
2022-04-28 3:40 ` Dave Hansen
2022-04-28 3:55 ` Kai Huang
2022-04-06 4:49 ` [PATCH v3 11/21] x86/virt/tdx: Choose to use " Kai Huang
2022-04-20 20:55 ` Isaku Yamahata
2022-04-20 22:39 ` Kai Huang
2022-04-28 15:54 ` Dave Hansen
2022-04-29 7:32 ` Kai Huang
2022-04-06 4:49 ` [PATCH v3 12/21] x86/virt/tdx: Create TDMRs to cover all system RAM Kai Huang
2022-04-28 16:22 ` Dave Hansen
2022-04-29 7:24 ` Kai Huang
2022-04-29 13:52 ` Dave Hansen
2022-04-06 4:49 ` [PATCH v3 13/21] x86/virt/tdx: Allocate and set up PAMTs for TDMRs Kai Huang
2022-04-28 17:12 ` Dave Hansen
2022-04-29 7:46 ` Kai Huang
2022-04-29 14:20 ` Dave Hansen
2022-04-29 14:30 ` Sean Christopherson
2022-04-29 17:46 ` Dave Hansen
2022-04-29 18:19 ` Sean Christopherson
2022-04-29 18:32 ` Dave Hansen
2022-05-02 5:59 ` Kai Huang
2022-05-02 14:17 ` Dave Hansen
2022-05-02 21:55 ` Kai Huang
2022-04-06 4:49 ` [PATCH v3 14/21] x86/virt/tdx: Set up reserved areas for all TDMRs Kai Huang
2022-04-06 4:49 ` [PATCH v3 15/21] x86/virt/tdx: Reserve TDX module global KeyID Kai Huang
2022-04-06 4:49 ` [PATCH v3 16/21] x86/virt/tdx: Configure TDX module with TDMRs and " Kai Huang
2022-04-06 4:49 ` [PATCH v3 17/21] x86/virt/tdx: Configure global KeyID on all packages Kai Huang
2022-04-06 4:49 ` [PATCH v3 18/21] x86/virt/tdx: Initialize all TDMRs Kai Huang
2022-04-06 4:49 ` [PATCH v3 19/21] x86: Flush cache of TDX private memory during kexec() Kai Huang
2022-04-06 4:49 ` [PATCH v3 20/21] x86/virt/tdx: Add kernel command line to opt-in TDX host support Kai Huang
2022-04-28 17:25 ` Dave Hansen
2022-04-06 4:49 ` [PATCH v3 21/21] Documentation/x86: Add documentation for " Kai Huang
2022-04-14 10:19 ` [PATCH v3 00/21] TDX host kernel support Kai Huang
2022-04-26 20:13 ` Dave Hansen
2022-04-27 1:15 ` Kai Huang
2022-04-27 21:59 ` Dave Hansen
2022-04-28 0:37 ` Kai Huang
2022-04-28 0:50 ` Dave Hansen
2022-04-28 0:58 ` Kai Huang
2022-04-29 1:40 ` Kai Huang
2022-04-29 3:04 ` Dan Williams
2022-04-29 5:35 ` Kai Huang
2022-05-03 23:59 ` Kai Huang
2022-05-04 0:25 ` Dave Hansen
2022-05-04 1:15 ` Kai Huang
2022-05-05 9:54 ` Kai Huang
2022-05-05 13:51 ` Dan Williams
2022-05-05 22:14 ` Kai Huang
2022-05-06 0:22 ` Dan Williams
2022-05-06 0:45 ` Kai Huang
2022-05-06 1:15 ` Dan Williams
2022-05-06 1:46 ` Kai Huang
2022-05-06 15:57 ` Dan Williams
2022-05-09 2:46 ` Kai Huang
2022-05-10 10:25 ` Kai Huang
2022-05-07 0:09 ` Mike Rapoport
2022-05-08 10:00 ` Kai Huang
2022-05-09 10:33 ` Mike Rapoport
2022-05-09 23:27 ` Kai Huang
2022-05-04 14:31 ` Dan Williams
2022-05-04 22:50 ` Kai Huang
2022-04-28 1:01 ` Dan Williams
2022-04-28 1:21 ` Kai Huang
2022-04-29 2:58 ` Dan Williams
2022-04-29 5:43 ` Kai Huang
2022-04-29 14:39 ` Dave Hansen
2022-04-29 15:18 ` Dan Williams
2022-04-29 17:18 ` Dave Hansen
2022-04-29 17:48 ` Dan Williams
2022-04-29 18:34 ` Dave Hansen
2022-04-29 18:47 ` Dan Williams
2022-04-29 19:20 ` Dave Hansen
2022-04-29 21:20 ` Dan Williams
2022-04-29 21:27 ` Dave Hansen
2022-05-02 10:18 ` Kai Huang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=966b1f45-ba5d-febd-e365-29308a9a59b4@intel.com \
--to=dave.hansen@intel.com \
--cc=ak@linux.intel.com \
--cc=dan.j.williams@intel.com \
--cc=isaku.yamahata@intel.com \
--cc=kai.huang@intel.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=kvm@vger.kernel.org \
--cc=len.brown@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=peterz@infradead.org \
--cc=rafael.j.wysocki@intel.com \
--cc=reinette.chatre@intel.com \
--cc=sathyanarayanan.kuppuswamy@linux.intel.com \
--cc=seanjc@google.com \
--cc=tony.luck@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).