From: "Huang, Kai" <kai.huang@intel.com>
To: Jarkko Sakkinen <jarkko@kernel.org>, Dave Hansen <dave.hansen@intel.com>
Cc: Andrew Zaborowski <andrew.zaborowski@intel.com>, <x86@kernel.org>,
<linux-sgx@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Tony Luck <tony.luck@intel.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@redhat.com>,
"H . Peter Anvin" <hpa@zytor.com>, <balrogg@gmail.com>
Subject: Re: [PATCH] x86: sgx: Don't track poisoned pages for reclaiming
Date: Wed, 12 Feb 2025 10:18:11 +1300 [thread overview]
Message-ID: <4a1c8b84-d8ee-414a-bd6d-a8633302dab4@intel.com> (raw)
In-Reply-To: <Z6u7PEQKb-L8X4e6@kernel.org>
On 12/02/2025 10:03 am, Jarkko Sakkinen wrote:
> On Tue, Feb 11, 2025 at 08:25:58AM -0800, Dave Hansen wrote:
>>> arch_memory_failure() but stay on sgx_active_page_list.
>>> page->poison is not checked in the reclaimer logic meaning that a page could be
>>> reclaimed and go through ETRACK, EBLOCK and EWB. This can lead to the
>>> firmware receiving and MCE in one of those operations and going into
>>> "unbreakable shutdown" and triggering a kernel panic on remaining cores.
>>
>> This requires low-level SGX implementation knowledge to fully
>> understand. Both what "ETRACK, EBLOCK and EWB" are in the first place,
>> how they are involved in reclaim and also why EREMOVE doesn't lead to
>> the same fate.
>
> Does it? [I'll dig up Intel SDM to check this]
>
I just did. :-)
It seems EREMOVE only reads and updates the EPCM entry for the target
EPC page but won't actually access that EPC page.
next prev parent reply other threads:[~2025-02-11 21:18 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-11 15:01 [PATCH] x86: sgx: Don't track poisoned pages for reclaiming Andrew Zaborowski
2025-02-11 16:25 ` Dave Hansen
2025-02-11 21:03 ` Jarkko Sakkinen
2025-02-11 21:18 ` Huang, Kai [this message]
2025-02-11 23:24 ` Jarkko Sakkinen
2025-02-11 23:31 ` Dave Hansen
2025-02-12 0:32 ` andrzej zaborowski
2025-02-12 0:37 ` Dave Hansen
2025-02-12 10:38 ` Huang, Kai
2025-02-12 21:25 ` Jarkko Sakkinen
2025-02-12 0:22 ` Andrew Zaborowski
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