Re: [PATCH 09/10] KVM: x86: Kill KVM_REQ_GLOBAL_CLOCK_UPDATE

[Paul Durrant]

On 18/04/2024 20:34, David Woodhouse wrote:
> From: David Woodhouse <dwmw@xxxxxxxxxxxx>
>
> This was introduced in commit 0061d53daf26 ("KVM: x86: limit difference
> between kvmclock updates") to reduce cross-vCPU differences which arose
> because the KVM clock was based on CLOCK_MONOTONIC and thus subject to
> NTP frequency corrections.
>
> However, commit 53fafdbb8b21 ("KVM: x86: switch KVMCLOCK base to
> monotonic raw clock") switched to using CLOCK_MONOTONIC_RAW as the basis
> for the KVM clock, avoiding the NTP frequency skew altogether.
>
> So remove KVM_REQ_GLOBAL_CLOCK_UPDATE. In kvm_write_system_time(), all
> that's needed is a single KVM_REQ_CLOCK_UPDATE for the vCPU whose KVM
> clock is being configured.
>
> Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
> ---
>   arch/x86/include/asm/kvm_host.h |  2 +-
>   arch/x86/kvm/x86.c              | 57 ++-------------------------------
>   2 files changed, 4 insertions(+), 55 deletions(-)

Reviewed-by: Paul Durrant <paul@xxxxxxx>