Fix: set RTC to localtime only for Windows/ReactOS/DOS and UTC for all others #1429
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
…er OS Windows/ReactOS/DOS conventionally set the system RTC to local time, but Linux/UNIX/macOS use UTC. Guest systems that expect UTC and have the time zone set to local time will have the wrong system clock time at startup until they set the clock with NTP. This is especially an issue for disk images imported from or shared with another VM configuration that uses UTC for non-Windows guests.
According to the QEMU man page:
Enable driftfix (i386 targets only) if you experience time
drift problems, specifically with Windows' ACPI HAL. This
option will try to figure out how many timer interrupts were
not processed by the Windows guest and will re-inject them.
This option thus seems unnecessary for other systems and may cause
performance or timekeeping issues, so enable only for
Windows/ReactOS/DOS.
chasecovello
changed the title
flexiondotorg
approved these changes
Aug 27, 2024
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Description
Windows/ReactOS/DOS conventionally set the system RTC to local time, but Linux/UNIX/macOS use UTC. Guest systems that expect UTC and have the time zone set to local time will have the wrong system clock time at startup until they set the clock with NTP. This is especially an issue for disk images imported from or shared with another VM configuration that uses UTC for non-Windows guests.
Further, according to the QEMU man page:
This option thus seems unnecessary for other systems and may cause performance or timekeeping issues, so enable only for Windows/ReactOS/DOS.
Type of change
Checklist: