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From: Dave Hansen <dave.hansen@intel.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
	Kuppuswamy Sathyanarayanan 
	<sathyanarayanan.kuppuswamy@linux.intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Elena Reshetova <elena.reshetova@intel.com>,
	x86@kernel.org, linux-coco@lists.linux.dev,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] x86/tdx: Use ReportFatalError to report missing SEPT_VE_DISABLE
Date: Thu, 15 Dec 2022 10:18:24 -0800	[thread overview]
Message-ID: <795d6e1d-c79c-b079-3412-69ca2f8ee874@intel.com> (raw)
In-Reply-To: <20221215171254.3v4maexfhkdnbfk2@box.shutemov.name>

On 12/15/22 09:12, Kirill A. Shutemov wrote:
>> Getting *all* users of panic this magic ability would be a lot better
>> than giving it to one call-site of panic().
>>
>> I'm all for making the panic() path as short and simple as possible, but
>> it would be nice if this fancy hypercall would get used in more than one
>> spot.
> Well, I don't see an obvious way to integrate this into panic().
> 
> There is panic_notifier_list and it kinda/sorta works, see the patch
> below.
> 
> But it breaks panic_notifier_list contract: the callback will never return
> and no other callback will be able to do their stuff. panic_timeout is
> also broken.
> 
> So ReportFatalError() is no good for the task. And I don't have anything
> else :/

Do we *really* have to do a hard stop when SEPT_VE_DISABLE is missing?

Wouldn't it be simpler to just defer the check until we can spit out a
sane error message about it?

Or is there too much security exposure by continuing?

  reply	other threads:[~2022-12-15 18:18 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-09 13:25 [PATCH 0/4] x86/tdx: Changes for TDX guest initialization Kirill A. Shutemov
2022-12-09 13:25 ` [PATCH 1/4] x86/tdx: Expand __tdx_hypercall() to handle more arguments Kirill A. Shutemov
2022-12-13 22:44   ` Dave Hansen
2022-12-09 13:25 ` [PATCH 2/4] x86/tdx: Use ReportFatalError to report missing SEPT_VE_DISABLE Kirill A. Shutemov
2022-12-09 15:42   ` Sathyanarayanan Kuppuswamy
2022-12-09 17:06     ` Kirill A. Shutemov
2022-12-09 20:51       ` Sathyanarayanan Kuppuswamy
2022-12-12 16:10         ` Dave Hansen
2022-12-12 16:37           ` Sathyanarayanan Kuppuswamy
2022-12-12 16:39             ` Dave Hansen
2022-12-13 23:06   ` Dave Hansen
2022-12-15 17:12     ` Kirill A. Shutemov
2022-12-15 18:18       ` Dave Hansen [this message]
2022-12-15 18:51         ` Kirill A. Shutemov
2022-12-15 21:09           ` Dave Hansen
2022-12-16  2:38             ` Kirill A. Shutemov
2022-12-16 15:22               ` Reshetova, Elena
2022-12-09 13:25 ` [PATCH 3/4] x86/tdx: Relax SEPT_VE_DISABLE check for debug TD Kirill A. Shutemov
2022-12-09 15:45   ` Sathyanarayanan Kuppuswamy
2022-12-09 17:08     ` Kirill A. Shutemov
2022-12-13 23:13   ` Dave Hansen
2022-12-15 15:40     ` Kirill A. Shutemov
2022-12-09 13:25 ` [PATCH 4/4] x86/tdx: Disable NOTIFY_ENABLES Kirill A. Shutemov
2022-12-09 15:50   ` Sathyanarayanan Kuppuswamy
2022-12-09 17:10     ` Kirill A. Shutemov
2022-12-13 23:17   ` Dave Hansen

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