Thread (115 messages) 115 messages, 12 authors, 2023-03-01

Re: [PATCH v6 14/41] x86/mm: Introduce _PAGE_SAVED_DIRTY

From: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
Date: 2023-02-21 20:08:49
Also in: linux-arch, linux-doc, linux-mm, lkml

On Tue, 2023-02-21 at 09:38 +0100, David Hildenbrand wrote:
Again, I'd not specialize on COW in all patches to much (IMHO, it 
creates more confusion than it actually helps for understanding
what's 
happening) and just call it a read-only PTE that is dirty. Simple as 
that. And it's easy to see why that's problematic, because read-only 
PTEs that are dirty would be identified as shadow stack PTEs, which
we 
want to work around.

Again, just my 2 cents. I'm not an x86 maintainer ;)
Right, I see the point. Let's see if they have any opinion. There is a
bit of a historical reason for the focus on COW. As you well know the
dirty bit used to be important for that case. But I think it's still
not a terrible example. It covers some typical cases, but yes we don't
want to mislead the reader that it is a Cow only scenario.
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