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From: Sean Christopherson <seanjc@google.com>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	david@redhat.com, lpivarc@redhat.com
Subject: Re: [PATCH] vfio/type1: Unpin zero pages
Date: Tue, 30 Aug 2022 05:34:51 +0000	[thread overview]
Message-ID: <Yw2heyQmvPgBe6f9@google.com> (raw)
In-Reply-To: <166182871735.3518559.8884121293045337358.stgit@omen>

On Mon, Aug 29, 2022, Alex Williamson wrote:
> There's currently a reference count leak on the zero page.  We increment
> the reference via pin_user_pages_remote(), but the page is later handled
> as an invalid/reserved page, therefore it's not accounted against the
> user and not unpinned by our put_pfn().

Heh, kvm_pfn_to_refcounted_page() all over again.  is_zone_device_page() is the
other known case where a PageReserved page is refcounted.  But as KVM's comment
calls out, KVM's list was built through trial and error.

  reply	other threads:[~2022-08-30  5:35 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-30  3:05 [PATCH] vfio/type1: Unpin zero pages Alex Williamson
2022-08-30  5:34 ` Sean Christopherson [this message]
2022-08-30  7:59 ` David Hildenbrand
2022-08-30 15:11   ` Alex Williamson
2022-08-30 15:43     ` David Hildenbrand
2022-09-02  0:53       ` Jason Gunthorpe
2022-09-02  8:24 ` Tian, Kevin
2022-09-02  8:32   ` David Hildenbrand
2022-09-02  9:09     ` Tian, Kevin
2022-09-06 23:30     ` Jason Gunthorpe
2022-09-07  9:00       ` David Hildenbrand
2022-09-07 12:48         ` Jason Gunthorpe
2022-09-07 15:55           ` Alex Williamson
2022-09-07 16:40             ` Jason Gunthorpe
2022-09-07 18:56               ` Alex Williamson
2022-09-07 19:14                 ` David Hildenbrand
2022-09-07 19:55                 ` Jason Gunthorpe
2022-09-07 20:24                   ` Alex Williamson
2022-09-07 23:07                     ` Jason Gunthorpe
2022-09-08  1:10                       ` Alex Williamson

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