Public bug reported:
[ Impact ]
When running on RISC-V under KVM the displayed time does not match the
wall-clock.
On a specific system U-Boot's and GRUB's count-down before booting where
10 times slower than expected.
Please, apply upstream patch
385e575cd5ab ("target/riscv/kvm: fix timebase-frequency when using KVM
acceleration")
to Ubuntu 22.04 Noble and 22.10 Oracular.
[ Test Plan ]
Boot a RISC-V virtual machine according to
https://wiki.ubuntu.com/RISC-V/QEMU. Inside the virtual machine start a
nested VM adding '-accel kvm' to the command line.
Do the same with '-accel tcg'
Check that the count-down in U-Boot and GRUB matches the wall time.
[ Where problems could occur ]
Only RISC-V code is changed.
VMs might not boot anymore.
The time-base frequency could still be wrong.
[ Other Info ]
n/a
** Affects: qemu (Ubuntu)
Importance: Undecided
Assignee: Heinrich Schuchardt (xypron)
Status: New
** Affects: qemu (Ubuntu Noble)
Importance: Undecided
Assignee: Heinrich Schuchardt (xypron)
Status: New
** Affects: qemu (Ubuntu Oracular)
Importance: Undecided
Assignee: Heinrich Schuchardt (xypron)
Status: New
** Attachment added: "Patch backported to v8.2.2"
https://bugs.launchpad.net/bugs/2076927/+attachment/5805457/+files/0001-target-riscv-kvm-fix-timebase-frequency-when-using-K.patch
** Changed in: qemu (Ubuntu)
Assignee: (unassigned) => Heinrich Schuchardt (xypron)
** Description changed:
[ Impact ]
When running on RISC-V under KVM the displayed time does not match the
wall-clock.
On a specific system U-Boot's and GRUB's count-down before booting where
10 times slower than expected.
Please, apply upstream patch
385e575cd5ab ("target/riscv/kvm: fix timebase-frequency when using KVM
acceleration")
+ to Ubuntu 22.04 Noble and 22.10 Oracular.
[ Test Plan ]
Boot a RISC-V virtual machine according to
https://wiki.ubuntu.com/RISC-V/QEMU. Inside the virtual machine start a
nested VM adding '-accel kvm' to the command line.
Do the same with '-accel tcg'
Check that the count-down in U-Boot and GRUB matches the wall time.
[ Where problems could occur ]
Only RISC-V code is changed.
VMs might not boot anymore.
The time-base frequency could still be wrong.
[ Other Info ]
-
+
n/a
** Also affects: qemu (Ubuntu Noble)
Importance: Undecided
Status: New
** Also affects: qemu (Ubuntu Oracular)
Importance: Undecided
Assignee: Heinrich Schuchardt (xypron)
Status: New
** Changed in: qemu (Ubuntu Noble)
Assignee: (unassigned) => Heinrich Schuchardt (xypron)
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https://bugs.launchpad.net/bugs/2076927
Title:
RISC-V: Incorrect time-base frequency in KVM
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