[SRU] RISC-V: Incorrect time-base frequency in KVM

[Heinrich Schuchardt]

[ 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

[Sergio Durigan Junior (sergiodj)]

I've uploaded QEMU 9.0.2 to Oracular yesterday and it has this fix, so I'm marking its task as Fix Released.

[Sergio Durigan Junior (sergiodj)]

@Heinrich, I'm preparing a batch of bugfixes for QEMU on Noble. I see you assigned this bug to yourself, but I'm going to reassign it to me just to reflect the fact that I'll be doing the upload.