From: Jason Gunthorpe <jgg@ziepe.ca>
To: Mircea CIRJALIU - MELIU <mcirjaliu@bitdefender.com>
Cc: "Adalbert Lazăr" <alazar@bitdefender.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-api@vger.kernel.org" <linux-api@vger.kernel.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Alexander Graf" <graf@amazon.com>,
"Stefan Hajnoczi" <stefanha@redhat.com>,
"Jerome Glisse" <jglisse@redhat.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Mihai Donțu" <mdontu@bitdefender.com>,
"Andy Lutomirski" <luto@kernel.org>,
"Arnd Bergmann" <arnd@arndb.de>,
"Sargun Dhillon" <sargun@sargun.me>,
"Aleksa Sarai" <cyphar@cyphar.com>,
"Oleg Nesterov" <oleg@redhat.com>, "Jann Horn" <jannh@google.com>,
"Kees Cook" <keescook@chromium.org>,
"Matthew Wilcox" <willy@infradead.org>,
"Christian Brauner" <christian.brauner@ubuntu.com>
Subject: Re: [RESEND RFC PATCH 0/5] Remote mapping
Date: Fri, 4 Sep 2020 11:39:03 -0300 [thread overview]
Message-ID: <20200904143903.GT24045@ziepe.ca> (raw)
In-Reply-To: <AM7PR02MB6082B1192A87C027DE2FD668BB2D0@AM7PR02MB6082.eurprd02.prod.outlook.com>
On Fri, Sep 04, 2020 at 02:18:37PM +0000, Mircea CIRJALIU - MELIU wrote:
> > This seems really sketchy, get_user_pages is sensitive to the VMA, what
> > happens when VMA flags are different/etc?
>
> A debugger shouldn't complain if a portion of the debuggee is read-only,
> just overwrite the data.
At this point the kernel API here is so incredibly limited you may as
well use a memfd for passing the shared address space instead of
trying to do and maintain this complexity.
Your use case is only qemu, so what is the problem to replace the
allocator backing VM memory in userspace? Other people have been
talking about doing a memfd already for different reasons - and memfd
can already be shared as this scheme desires.
Jason
next prev parent reply other threads:[~2020-09-04 14:39 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-04 11:31 [RESEND RFC PATCH 0/5] Remote mapping Adalbert Lazăr
2020-09-04 11:31 ` [RESEND RFC PATCH 1/5] mm: add atomic capability to zap_details Adalbert Lazăr
2020-09-04 11:31 ` [RESEND RFC PATCH 2/5] mm: let the VMA decide how zap_pte_range() acts on mapped pages Adalbert Lazăr
2020-09-04 11:31 ` [RESEND RFC PATCH 3/5] mm/mmu_notifier: remove lockdep map, allow mmu notifier to be used in nested scenarios Adalbert Lazăr
2020-09-04 12:03 ` Jason Gunthorpe
2020-09-04 11:31 ` [RESEND RFC PATCH 4/5] mm/remote_mapping: use a pidfd to access memory belonging to unrelated process Adalbert Lazăr
2020-09-04 17:55 ` Oleg Nesterov
2020-09-07 14:30 ` Oleg Nesterov
2020-09-07 15:16 ` Adalbert Lazăr
2020-09-09 8:32 ` Mircea CIRJALIU - MELIU
2020-09-10 16:43 ` Oleg Nesterov
2020-09-07 15:02 ` Christian Brauner
2020-09-07 16:04 ` Mircea CIRJALIU - MELIU
2020-09-04 11:31 ` [RESEND RFC PATCH 5/5] pidfd_mem: implemented remote memory mapping system call Adalbert Lazăr
2020-09-04 19:18 ` Florian Weimer
2020-09-07 14:55 ` Christian Brauner
2020-09-04 12:11 ` [RESEND RFC PATCH 0/5] Remote mapping Jason Gunthorpe
2020-09-04 13:24 ` Mircea CIRJALIU - MELIU
2020-09-04 13:39 ` Jason Gunthorpe
2020-09-04 14:18 ` Mircea CIRJALIU - MELIU
2020-09-04 14:39 ` Jason Gunthorpe [this message]
2020-09-04 15:40 ` Mircea CIRJALIU - MELIU
2020-09-04 16:11 ` Jason Gunthorpe
2020-09-04 19:41 ` Matthew Wilcox
2020-09-04 19:49 ` Jason Gunthorpe
2020-09-04 20:08 ` Paolo Bonzini
2020-12-01 18:01 ` Jason Gunthorpe
2020-09-04 19:19 ` Florian Weimer
2020-09-04 20:18 ` Paolo Bonzini
2020-09-07 8:33 ` Christian Brauner
2020-09-04 19:39 ` Andy Lutomirski
2020-09-04 20:09 ` Paolo Bonzini
2020-09-04 20:34 ` Andy Lutomirski
2020-09-04 21:58 ` Paolo Bonzini
2020-09-04 23:17 ` Andy Lutomirski
2020-09-05 18:27 ` Paolo Bonzini
2020-09-07 8:38 ` Christian Brauner
2020-09-07 12:41 ` Mircea CIRJALIU - MELIU
2020-09-07 7:05 ` Christoph Hellwig
2020-09-07 8:44 ` Paolo Bonzini
2020-09-07 10:25 ` Mircea CIRJALIU - MELIU
2020-09-07 15:05 ` Christian Brauner
2020-09-07 20:43 ` Andy Lutomirski
2020-09-09 11:38 ` Stefan Hajnoczi
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