linux-kernel - Re: [PATCH v2] x86/sgx: Prevent attempts to reclaim poisoned pages

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Message-ID: <448598e9-972f-4807-ba54-fc1f7e141b4f@intel.com>
Date: Thu, 15 May 2025 09:27:21 -0700
From: Dave Hansen <dave.hansen@...el.com>
To: Andrew Zaborowski <andrew.zaborowski@...el.com>, x86@...nel.org,
 linux-sgx@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: Dave Hansen <dave.hansen@...ux.intel.com>, Tony Luck
 <tony.luck@...el.com>, Thomas Gleixner <tglx@...utronix.de>,
 Borislav Petkov <bp@...en8.de>, Ingo Molnar <mingo@...hat.com>,
 "H . Peter Anvin" <hpa@...or.com>, balrogg@...il.com
Subject: Re: [PATCH v2] x86/sgx: Prevent attempts to reclaim poisoned pages

Thanks for sending this, Andrew!

I think I'll probably add a slightly shorter summary:

tl;dr: SGX page reclaim touches the page to copy its contents to
secondary storage. SGX instructions do not gracefully handle machine
checks. Despite this, the existing SGX code will try to reclaim pages
that it _knows_ are poisoned. Avoid even trying to reclaim poisoned pages.

But otherwise it looks great:

Acked-by: Dave Hansen <dave.hansen@...ux.intel.com>