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[PATCH 0/2] Convert sparc devices to new ptimer API
From: |
Peter Maydell |
Subject: |
[PATCH 0/2] Convert sparc devices to new ptimer API |
Date: |
Thu, 17 Oct 2019 14:23:49 +0100 |
This patchset converts the devices used by sparc machines to the new
ptimer API.
Currently the ptimer design uses a QEMU bottom-half as its mechanism
for calling back into the device model using the ptimer when the
timer has expired. Unfortunately this design is fatally flawed,
because it means that there is a lag between the ptimer updating its
own state and the device callback function updating device state, and
guest accesses to device registers between the two can return
inconsistent device state. This was reported as a bug in a specific
timer device but it's a problem with the generic ptimer code:
https://bugs.launchpad.net/qemu/+bug/1777777
The updates to the individual ptimer devices are straightforward:
we need to add begin/commit calls around the various places that
modify the ptimer state, and use the new ptimer_init() function
to create the timer.
Testing has been 'make check', and a quick smoke test of a sparc
linux boot image I had lying around, which obviously doesn't
exercise the devices very much, so more specific testing would
be appreciated. I'm happy for these patches to go in via the
sparc tree if you want, or I can collect them up with the other
ptimer-related changes I'm sending for other archs.
thanks
--PMM
Peter Maydell (2):
hw/timer/grlib_gptimer.c: Switch to transaction-based ptimer API
hw/timer/slavio_timer.c: Switch to transaction-based ptimer API
hw/timer/grlib_gptimer.c | 28 ++++++++++++++++++++++++----
hw/timer/slavio_timer.c | 20 ++++++++++++++++----
2 files changed, 40 insertions(+), 8 deletions(-)
--
2.20.1
- [PATCH 0/2] Convert sparc devices to new ptimer API,
Peter Maydell <=
[PATCH 1/2] hw/timer/grlib_gptimer.c: Switch to transaction-based ptimer API, Peter Maydell, 2019/10/17
Re: [PATCH 0/2] Convert sparc devices to new ptimer API, Mark Cave-Ayland, 2019/10/20