Re: [PATCH v11 0/2] target/riscv: Fix riscv64 KVM migration

On Sat, 2026-08-08 at 20:51 +0800, Xie Bo wrote:
> This series revives v9, which was applied to riscv-to-apply.next but
> did
> not reach QEMU master.
> 
> RISC-V KVM migration currently loses two pieces of vCPU state: the
> privilege mode core register and KVM MP state. The latter leaves
> secondary
> vCPUs in their reset STOPPED state on the destination.
> 
> Synchronize the privilege mode through the existing generic CPU
> VMState,
> and carry MP state in a capability-gated KVM-only subsection. The
> subsection
> keeps KVM state out of TCG migration streams. Bump the generic RISC-V
> CPU
> VMState version and minimum version to 12 as required by the new
> pre_load
> hook and subsection.
> 
> Changes from v10:
> - Bump the RISC-V CPU VMState version_id and minimum_version_id to
> 12.
> - Add Daniel's Reviewed-by tags.
> 
> Testing on a native riscv64 host with Linux 6.6.20 and GCC 13.3.0:
> - KVM build: riscv64-softmmu, --enable-kvm.
> - Non-KVM build: riscv64-softmmu, --disable-kvm.
> - Four-vCPU KVM migration on unmodified master: all vCPUs failed to
> run
>   after migration and the guest reported RCU stalls.
> - The same migration with this series: CPU0 through CPU3 all ran
> after
>   migration.
> - Four user-mode busy workers, one pinned to each vCPU, all made
> forward
>   progress across migration to exercise privilege-mode restoration.

Thanks!

Applied to riscv-to-apply.next

Alistair

> 
> Xie Bo (2):
>   target/riscv/kvm: Synchronize privilege mode
>   target/riscv/kvm: Preserve MP state across migration
> 
>  target/riscv/cpu.h           |  4 +++
>  target/riscv/kvm/kvm-cpu.c   | 62 ++++++++++++++++++++++++++--------
> --
>  target/riscv/kvm/kvm_riscv.h |  2 +-
>  target/riscv/machine.c       | 49 ++++++++++++++++++++++++++--
>  4 files changed, 98 insertions(+), 19 deletions(-)