On 24/10/2019 13:19, Peter Maydell wrote: > On Mon, 21 Oct 2019 at 14:43, Peter Maydell <peter.mayd...@linaro.org> wrote: >> >> 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. >> >> Changes v1->v2: >> * patches 2 and 3 are the old 1 and 2 and have been reviewed >> * patch 1 is new and removes a pointless NULL check; without >> this we'd probably have got Coverity errors when patch 3 >> added a use of t->timer before the check for it being NULL > > I'm going to apply these to target-arm.next; I know they haven't > been on list long but the change since v1 is only minor and > they've all been reviewed.
Thanks Peter! Not sure if you saw my Tested-by tag last week for the slavio (sun4m) parts, but there were no obvious regressions that I could see under qemu-system-sparc. ATB, Mark.
