Re: [Qemu-devel] [PATCH] i386/kvm: Do not sync nested state during runtime

[Liran Alon]

> On 22 Jul 2019, at 7:00, Jan Kiszka <address@hidden> wrote:
> 
> Writing the nested state e.g. after a vmport access can invalidate
> important parts of the kernel-internal state, and it is not needed as
> well. So leave this out from KVM_PUT_RUNTIME_STATE.
> 
> Suggested-by: Paolo Bonzini <address@hidden>
> Signed-off-by: Jan Kiszka <address@hidden>

As QEMU never modifies vCPU nested-state in userspace besides in vmload and 
vCPU creation,
shouldn’t this be under KVM_PUT_FULL_STATE? Same as the call to 
kvm_arch_set_tsc_khz().

-Liran 

> ---
> target/i386/kvm.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> index ec7870c6af..da98b2cbca 100644
> --- a/target/i386/kvm.c
> +++ b/target/i386/kvm.c
> @@ -3577,12 +3577,12 @@ int kvm_arch_put_registers(CPUState *cpu, int level)
> 
>     assert(cpu_is_stopped(cpu) || qemu_cpu_is_self(cpu));
> 
> -    ret = kvm_put_nested_state(x86_cpu);
> -    if (ret < 0) {
> -        return ret;
> -    }
> -
>     if (level >= KVM_PUT_RESET_STATE) {
> +        ret = kvm_put_nested_state(x86_cpu);
> +        if (ret < 0) {
> +            return ret;
> +        }
> +
>         ret = kvm_put_msr_feature_control(x86_cpu);
>         if (ret < 0) {
>             return ret;
> -- 
> 2.16.4