From: "M. Vefa Bicakci" <m.v.b@runbox.com>
To: Juergen Gross <jgross@suse.com>,
xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org
Cc: Stefano Stabellini <sstabellini@kernel.org>,
Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>,
Demi Marie Obenour <demi@invisiblethingslab.com>,
Gerd Hoffmann <kraxel@redhat.com>
Subject: Re: [PATCH v2 0/2] xen/gntdev: Fixes for leaks and VMA splitting
Date: Sat, 8 Oct 2022 11:17:20 -0400 [thread overview]
Message-ID: <9cdb37b7-b4c0-3bc3-ecdc-643ddc2fbcc5@runbox.com> (raw)
In-Reply-To: <9aa1e6ba-a153-8dfa-ce28-3ab78b26c6e4@suse.com>
On 2022-10-07 01:17, Juergen Gross wrote:
> On 03.10.22 00:20, M. Vefa Bicakci wrote:
>> Hi all,
>>
>> First of all, sorry for the delay!
>>
>> These patches continue the code review for the following patches:
>> https://lore.kernel.org/xen-devel/20220912040002.198191-1-m.v.b@runbox.com/t/#u
>>
>> The original description of the patch set is as follows:
>>
>> "The changes in this patch series intend to fix the Xen grant device
>> driver, so that grant mapping leaks caused by partially failed grant
>> mapping operations are avoided with the first patch, and so that the
>> splitting of VMAs does not result in incorrectly unmapped grant pages
>> with the second patch. The second patch also prevents a similar issue
>> in a double-mapping scenario, where mmap() is used with MAP_FIXED to
>> map grants over an existing mapping created with the same grants, and
>> where grant pages are unmapped incorrectly as well."
>>
>> A summary of the changes from v1 is as follows:
>> - Addressed Juergen's code review comment regarding the first patch.
>> - Amended the description of the second patch to note that the described
>> issues are encountered with PV domains.
>>
>> Verification notes:
>>
>> - I have tested these commits on top of Linux v5.15.70 and v5.15.71, and
>> I verified that they compile successfully on top of the tag
>> "next-20220930", which corresponds to the base commit ID included at
>> the bottom of this e-mail.
>>
>> - My tests consist of using a kernel with Qubes OS v4.1's patches and
>> these patches on my main computer for day-to-day tasks, in conjunction
>> with Qubes OS's version of the Xen hypervisor v4.14.5, with the latter
>> custom-compiled with CONFIG_DEBUG.
>>
>> - I used a test program that verifies the following scenarios with an
>> unprivileged paravirtualized (PV) Xen domain:
>>
>> - A program mmap()s two pages from another Xen domain and munmap()s
>> the pages one by one. This used to result in implicit unmap errors
>> to be reported by Xen and a general protection fault to be triggered
>> by Xen in the affected domain, but now works as expected.
>> - A program mmap()s two pages from another Xen domain and then
>> attempts to remap (via MAP_FIXED) the same mapping again over the
>> same virtual address. This used to result in similar issues
>> (implicit unmap errors and general protection fault), but now is
>> rejected by the kernel.
>> - A program mmap()s two pages from another Xen domain and then
>> attempts to mmap() the same mapping again to a different virtual
>> address, by passing NULL as mmap()'s first argument. This used to be
>> rejected by the kernel, and it continues to be rejected by the
>> kernel.
>>
>> - Unprivileged PVH Xen domains were also sanity tested with the same
>> test program. I should note that PVH domains worked as expected
>> without these patches too.
>>
>> - Finally, I have verified that the original "g.e. 0x1234 still pending"
>> issue does not appear after rapidly resizing GUI windows in Qubes OS
>> v4.1.
>
> Series pushed to xen/tip.git for-linus-6.1
>
>
> Juergen
I am a bit late, but thank you for reviewing the changes and merging them!
Vefa
prev parent reply other threads:[~2022-10-08 15:17 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-02 22:20 [PATCH v2 0/2] xen/gntdev: Fixes for leaks and VMA splitting M. Vefa Bicakci
2022-10-02 22:20 ` [PATCH v2 1/2] xen/gntdev: Prevent leaking grants M. Vefa Bicakci
2022-10-03 0:29 ` Demi Marie Obenour
2022-10-04 1:31 ` M. Vefa Bicakci
2022-10-04 1:51 ` Demi Marie Obenour
2022-10-05 1:37 ` M. Vefa Bicakci
2022-10-06 8:33 ` Juergen Gross
2022-10-02 22:20 ` [PATCH v2 2/2] xen/gntdev: Accommodate VMA splitting M. Vefa Bicakci
2022-10-06 8:36 ` Juergen Gross
2022-10-07 5:17 ` [PATCH v2 0/2] xen/gntdev: Fixes for leaks and " Juergen Gross
2022-10-07 17:31 ` Demi Marie Obenour
2022-10-08 15:17 ` M. Vefa Bicakci [this message]
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