From: David Hildenbrand <david@redhat.com>
To: Jason Gunthorpe <jgg@nvidia.com>, Fuad Tabba <tabba@google.com>
Cc: John Hubbard <jhubbard@nvidia.com>,
Elliot Berman <quic_eberman@quicinc.com>,
Andrew Morton <akpm@linux-foundation.org>,
Shuah Khan <shuah@kernel.org>,
Matthew Wilcox <willy@infradead.org>,
maz@kernel.org, kvm@vger.kernel.org,
linux-arm-msm@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
pbonzini@redhat.com
Subject: Re: [PATCH RFC 0/5] mm/gup: Introduce exclusive GUP pinning
Date: Wed, 19 Jun 2024 14:17:23 +0200 [thread overview]
Message-ID: <095dd4fb-956b-40f4-984d-14544d726f97@redhat.com> (raw)
In-Reply-To: <20240619115135.GE2494510@nvidia.com>
> If the memory can't be accessed by the CPU then it shouldn't be mapped
> into a PTE in the first place. The fact you made userspace faults
> (only) work is nifty but still an ugly hack to get around the fact you
> shouldn't be mapping in the first place.
>
> We already have ZONE_DEVICE/DEVICE_PRIVATE to handle exactly this
> scenario. "memory" that cannot be touched by the CPU but can still be
> specially accessed by enlightened components.
>
> guest_memfd, and more broadly memfd based instead of VMA based, memory
> mapping in KVM is a similar outcome to DEVICE_PRIVATE.
>
> I think you need to stay in the world of not mapping the memory, one
> way or another.
Fully agreed. Private memory shall not be mapped.
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2024-06-19 12:17 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-19 0:05 [PATCH RFC 0/5] mm/gup: Introduce exclusive GUP pinning Elliot Berman
2024-06-19 0:05 ` [PATCH RFC 1/5] mm/gup: Move GUP_PIN_COUNTING_BIAS to page_ref.h Elliot Berman
2024-06-19 0:05 ` [PATCH RFC 2/5] mm/gup: Add an option for obtaining an exclusive pin Elliot Berman
2024-06-19 0:05 ` [PATCH RFC 3/5] mm/gup: Add support for re-pinning a normal pinned page as exclusive Elliot Berman
2024-06-19 0:05 ` [PATCH RFC 4/5] mm/gup-test: Verify exclusive pinned Elliot Berman
2024-06-19 0:05 ` [PATCH RFC 5/5] mm/gup_test: Verify GUP grabs same pages twice Elliot Berman
2024-06-19 0:11 ` [PATCH RFC 0/5] mm/gup: Introduce exclusive GUP pinning Elliot Berman
2024-06-19 2:44 ` John Hubbard
2024-06-19 7:37 ` David Hildenbrand
2024-06-19 9:11 ` Fuad Tabba
2024-06-19 11:51 ` Jason Gunthorpe
2024-06-19 12:01 ` Fuad Tabba
2024-06-19 12:42 ` Jason Gunthorpe
2024-06-20 15:37 ` Sean Christopherson
2024-06-21 8:23 ` Fuad Tabba
2024-06-21 8:43 ` David Hildenbrand
2024-06-21 8:54 ` Fuad Tabba
2024-06-21 9:10 ` David Hildenbrand
2024-06-21 10:16 ` Fuad Tabba
2024-06-21 16:54 ` Elliot Berman
2024-06-24 19:03 ` Sean Christopherson
2024-06-24 21:50 ` David Rientjes
2024-06-26 3:19 ` Vishal Annapurve
2024-06-26 5:20 ` Pankaj Gupta
2024-06-19 12:17 ` David Hildenbrand [this message]
2024-06-20 4:11 ` Christoph Hellwig
2024-06-20 8:32 ` Fuad Tabba
2024-06-20 13:55 ` Jason Gunthorpe
2024-06-20 14:01 ` David Hildenbrand
2024-06-20 14:29 ` Jason Gunthorpe
2024-06-20 14:45 ` David Hildenbrand
2024-06-20 16:04 ` Sean Christopherson
2024-06-20 18:56 ` David Hildenbrand
2024-06-20 16:36 ` Jason Gunthorpe
2024-06-20 18:53 ` David Hildenbrand
2024-06-20 20:30 ` Sean Christopherson
2024-06-20 20:47 ` David Hildenbrand
2024-06-20 22:32 ` Sean Christopherson
2024-06-20 23:00 ` Jason Gunthorpe
2024-06-20 23:11 ` Jason Gunthorpe
2024-06-20 23:54 ` Sean Christopherson
2024-06-21 7:43 ` David Hildenbrand
2024-06-21 12:39 ` Jason Gunthorpe
2024-06-20 23:08 ` Jason Gunthorpe
2024-06-20 22:47 ` Elliot Berman
2024-06-20 23:18 ` Jason Gunthorpe
2024-06-21 7:32 ` Quentin Perret
2024-06-21 8:02 ` David Hildenbrand
2024-06-21 9:25 ` Quentin Perret
2024-06-21 9:37 ` David Hildenbrand
2024-06-21 16:48 ` Elliot Berman
2024-06-21 12:26 ` Jason Gunthorpe
2024-06-19 12:16 ` David Hildenbrand
2024-06-20 8:47 ` Fuad Tabba
2024-06-20 9:00 ` David Hildenbrand
2024-06-20 14:01 ` Jason Gunthorpe
2024-06-20 13:08 ` Mostafa Saleh
2024-06-20 14:14 ` David Hildenbrand
2024-06-20 14:34 ` Jason Gunthorpe
2024-08-02 8:26 ` Tian, Kevin
2024-08-02 11:22 ` Jason Gunthorpe
2024-08-05 2:24 ` Tian, Kevin
2024-08-05 23:22 ` Jason Gunthorpe
2024-08-06 0:50 ` Tian, Kevin
2024-06-20 16:33 ` Mostafa Saleh
2024-07-12 23:29 ` Ackerley Tng
2024-07-16 16:03 ` Sean Christopherson
2024-07-16 16:08 ` Jason Gunthorpe
2024-07-16 17:34 ` Sean Christopherson
2024-07-16 20:11 ` Jason Gunthorpe
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