From: Ahmed Karaman <1880722@bugs.launchpad.net>
To: qemu-devel@nongnu.org
Subject: [Bug 1880722] Re: Problems related to checking page crossing in use_goto_tb()
Date: Tue, 26 May 2020 17:00:57 -0000 [thread overview]
Message-ID: <159051245801.8264.18308114750913433257.launchpad@gac.canonical.com> (raw)
In-Reply-To: 159050902512.8264.16089666576245848412.malonedeb@gac.canonical.com
** Summary changed:
- Changing executable page permissions with mmap causes user-mode failures
+ Problems related to checking page crossing in use_goto_tb()
** Description changed:
- The discussion that led to this bug discovery can be found in this
+ The discussion that led to this bug discovery can be found in this
mailing list thread:
https://lists.nongnu.org/archive/html/qemu-devel/2020-05/msg05426.html
- A workaround for this problem would be to check for page crossings for
- both the user and system modes in the use_goto_tb() function across
+ A workaround for this problem would be to check for page crossings for
+ both the user and system modes in the use_goto_tb() function across
targets. Some targets like "hppa" already implement this fix but others
don't.
- To solve the root cause of this problem, the linux-user/mmap.c should
- be fixed to do all the invalidations required. By doing so, up to 6.93%
- performance improvements will be achieved.
+ To solve the root cause of this problem, the linux-user/mmap.c should
+ be fixed to do all the invalidations required. By doing so, better
+ performance results could be achieved, compared to the case of the
+ workaround described above.
--
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https://bugs.launchpad.net/bugs/1880722
Title:
Problems related to checking page crossing in use_goto_tb()
Status in QEMU:
New
Bug description:
The discussion that led to this bug discovery can be found in this
mailing list thread:
https://lists.nongnu.org/archive/html/qemu-devel/2020-05/msg05426.html
A workaround for this problem would be to check for page crossings for
both the user and system modes in the use_goto_tb() function across
targets. Some targets like "hppa" already implement this fix but others
don't.
To solve the root cause of this problem, the linux-user/mmap.c should
be fixed to do all the invalidations required. By doing so, better
performance results could be achieved, compared to the case of the
workaround described above.
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1880722/+subscriptions
next prev parent reply other threads:[~2020-05-26 17:11 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-26 16:03 [Bug 1880722] [NEW] Changing executable page permissions with mmap causes user-mode failures Ahmed Karaman
2020-05-26 16:30 ` [Bug 1880722] " Ahmed Karaman
2020-05-26 17:00 ` Ahmed Karaman [this message]
2021-05-06 17:15 ` [Bug 1880722] Re: Problems related to checking page crossing in use_goto_tb() Thomas Huth
2021-07-06 4:17 ` Launchpad Bug Tracker
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