linux-kernel - Re: [GIT PULL] VFIO updates for v6.17-rc1

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Message-ID: <db30f547-ba98-490c-aaf7-6b141bb1b52a@redhat.com>
Date: Tue, 5 Aug 2025 14:41:38 +0200
From: David Hildenbrand <david@...hat.com>
To: Jason Gunthorpe <jgg@...dia.com>
Cc: Alex Williamson <alex.williamson@...hat.com>,
 Linus Torvalds <torvalds@...ux-foundation.org>,
 "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
 "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
 "lizhe.67@...edance.com" <lizhe.67@...edance.com>
Subject: Re: [GIT PULL] VFIO updates for v6.17-rc1

On 05.08.25 14:38, Jason Gunthorpe wrote:
> On Tue, Aug 05, 2025 at 02:07:49PM +0200, David Hildenbrand wrote:
>> I don't see an easy way to guarantee that. E.g., populate_section_memmap
>> really just does a kvmalloc_node() and
>> __populate_section_memmap()->memmap_alloc() a memblock_alloc().
> 
> Well, it is really easy, if you do the kvmalloc_node and you get the
> single unwanted struct page value, then call it again and free the
> first one. The second call is guarenteed to not return the unwanted
> value because the first call has it allocated.

So you want to walk all existing sections to check that? :)

That's the kind of approach I would describe with the words Linus used.

-- 
Cheers,

David / dhildenb