From: Dave Hansen <dave.hansen@intel.com>
To: Peter Zijlstra <peterz@infradead.org>, Kai Huang <kai.huang@intel.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
linux-mm@kvack.org, tglx@linutronix.de, seanjc@google.com,
pbonzini@redhat.com, dan.j.williams@intel.com,
rafael.j.wysocki@intel.com, kirill.shutemov@linux.intel.com,
ying.huang@intel.com, reinette.chatre@intel.com,
len.brown@intel.com, tony.luck@intel.com, ak@linux.intel.com,
isaku.yamahata@intel.com, chao.gao@intel.com,
sathyanarayanan.kuppuswamy@linux.intel.com, david@redhat.com,
bagasdotme@gmail.com, sagis@google.com, imammedo@redhat.com
Subject: Re: [PATCH v9 04/18] x86/virt/tdx: Add skeleton to initialize TDX on demand
Date: Tue, 14 Feb 2023 09:23:40 -0800 [thread overview]
Message-ID: <a44246e1-72de-4c9a-c602-dfc2f7df129b@intel.com> (raw)
In-Reply-To: <Y+uCtZ7itiNsbR4j@hirez.programming.kicks-ass.net>
On 2/14/23 04:46, Peter Zijlstra wrote:
> On Tue, Feb 14, 2023 at 12:59:11AM +1300, Kai Huang wrote:
>> Use a state machine protected by mutex to make sure the initialization
>> will only be done once, as tdx_enable() can be called multiple times
>> (i.e. KVM module can be reloaded) and be called concurrently by other
>> kernel components in the future.
> I still object to doing tdx_enable() at kvm module load.
>
> kvm.ko gets loaded unconditionally on boot, even if I then never use
> kvm.
>
> This stuff needs to be done when an actual VM is created, not before.
The actually implementation of this is hidden over in the KVM side of
this. But, tdx_enable() and all of this jazz should not be called on
kvm.ko load. It'll happen when the KVM tries to start the first TDX VM.
I think what Kai was thinking of was *this* sequence:
1. insmod kvm.ko
2. Start a TDX guest, tdx_enable() gets run
3. rmmod kvm
4. insmod kvm.ko (again)
5. Start another TDX guest, run tdx_enable() (again)
The rmmod/insmod pair is what triggers the second call of tdx_enable().
next prev parent reply other threads:[~2023-02-14 17:23 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-13 11:59 [PATCH v9 00/18] TDX host kernel support Kai Huang
2023-02-13 11:59 ` [PATCH v9 01/18] x86/tdx: Define TDX supported page sizes as macros Kai Huang
2023-02-13 11:59 ` [PATCH v9 02/18] x86/virt/tdx: Detect TDX during kernel boot Kai Huang
2023-02-13 11:59 ` [PATCH v9 03/18] x86/virt/tdx: Make INTEL_TDX_HOST depend on X86_X2APIC Kai Huang
2023-02-13 11:59 ` [PATCH v9 04/18] x86/virt/tdx: Add skeleton to initialize TDX on demand Kai Huang
2023-02-14 12:46 ` Peter Zijlstra
2023-02-14 17:23 ` Dave Hansen [this message]
2023-02-14 21:08 ` Huang, Kai
2023-02-13 11:59 ` [PATCH v9 05/18] x86/virt/tdx: Add SEAMCALL infrastructure Kai Huang
2023-02-13 17:48 ` Dave Hansen
2023-02-13 21:21 ` Huang, Kai
2023-02-13 22:39 ` Dave Hansen
2023-02-13 23:22 ` Huang, Kai
2023-02-14 8:57 ` Huang, Kai
2023-02-14 17:27 ` Dave Hansen
2023-02-14 22:17 ` Huang, Kai
2023-02-14 12:42 ` Peter Zijlstra
2023-02-14 21:02 ` Huang, Kai
2023-02-13 11:59 ` [PATCH v9 06/18] x86/virt/tdx: Do TDX module global initialization Kai Huang
2023-02-13 11:59 ` [PATCH v9 07/18] x86/virt/tdx: Do TDX module per-cpu initialization Kai Huang
2023-02-13 17:59 ` Dave Hansen
2023-02-13 21:19 ` Huang, Kai
2023-02-13 22:43 ` Dave Hansen
2023-02-14 0:02 ` Huang, Kai
2023-02-14 14:12 ` Peter Zijlstra
2023-02-14 22:53 ` Huang, Kai
2023-02-15 9:16 ` Peter Zijlstra
2023-02-15 9:46 ` Huang, Kai
2023-02-15 13:25 ` Peter Zijlstra
2023-02-15 21:37 ` Huang, Kai
2023-03-06 14:26 ` Huang, Kai
2023-02-13 18:07 ` Dave Hansen
2023-02-13 21:13 ` Huang, Kai
2023-02-13 22:28 ` Dave Hansen
2023-02-13 23:43 ` Huang, Kai
2023-02-13 23:52 ` Dave Hansen
2023-02-14 0:09 ` Huang, Kai
2023-02-14 14:12 ` Peter Zijlstra
2023-02-14 12:59 ` Peter Zijlstra
2023-02-13 11:59 ` [PATCH v9 08/18] x86/virt/tdx: Get information about TDX module and TDX-capable memory Kai Huang
2023-02-13 11:59 ` [PATCH v9 09/18] x86/virt/tdx: Use all system memory when initializing TDX module as TDX memory Kai Huang
2023-02-14 3:30 ` Huang, Ying
2023-02-14 8:24 ` Huang, Kai
2023-02-13 11:59 ` [PATCH v9 10/18] x86/virt/tdx: Add placeholder to construct TDMRs to cover all TDX memory regions Kai Huang
2023-02-13 11:59 ` [PATCH v9 11/18] x86/virt/tdx: Fill out " Kai Huang
2023-02-13 11:59 ` [PATCH v9 12/18] x86/virt/tdx: Allocate and set up PAMTs for TDMRs Kai Huang
2023-02-13 11:59 ` [PATCH v9 13/18] x86/virt/tdx: Designate reserved areas for all TDMRs Kai Huang
2023-02-13 11:59 ` [PATCH v9 14/18] x86/virt/tdx: Configure TDX module with the TDMRs and global KeyID Kai Huang
2023-02-13 11:59 ` [PATCH v9 15/18] x86/virt/tdx: Configure global KeyID on all packages Kai Huang
2023-02-13 11:59 ` [PATCH v9 16/18] x86/virt/tdx: Initialize all TDMRs Kai Huang
2023-02-13 11:59 ` [PATCH v9 17/18] x86/virt/tdx: Flush cache in kexec() when TDX is enabled Kai Huang
2023-02-13 11:59 ` [PATCH v9 18/18] Documentation/x86: Add documentation for TDX host support Kai Huang
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