Messages in this thread | | | From | Yifei Jiang <> | Subject | [PATCH RFC 0/3] Implement guest time scaling in RISC-V KVM | Date | Thu, 3 Dec 2020 20:18:36 +0800 |
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This series implements guest time scaling based on RDTIME instruction emulation so that we can allow migrating Guest/VM across Hosts with different time frequency.
Why not through para-virt. From arm's experience[1], para-virt implementation doesn't really solve the problem for the following two main reasons: - RDTIME not only be used in linux, but also in firmware and userspace. - It is difficult to be compatible with nested virtualization.
[1] https://lore.kernel.org/patchwork/cover/1288153/
Yifei Jiang (3): RISC-V: KVM: Change the method of calculating cycles to nanoseconds RISC-V: KVM: Support dynamic time frequency from userspace RISC-V: KVM: Implement guest time scaling
arch/riscv/include/asm/csr.h | 3 ++ arch/riscv/include/asm/kvm_vcpu_timer.h | 13 +++++-- arch/riscv/kvm/vcpu_exit.c | 35 +++++++++++++++++ arch/riscv/kvm/vcpu_timer.c | 51 ++++++++++++++++++++++--- 4 files changed, 93 insertions(+), 9 deletions(-)
-- 2.19.1
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