Re: [Qemu-devel] [PATCH] target/i386: kvm: Fix when nested state is needed for migration

[Paolo Bonzini]

On 25/06/19 01:05, Liran Alon wrote:
> When vCPU is in VMX operation and enters SMM mode,
> it temporarily exits VMX operation but KVM maintained nested-state
> still stores the VMXON region physical address, i.e. even when the
> vCPU is in SMM mode then (nested_state->hdr.vmx.vmxon_pa != -1ull).
> 
> Therefore, there is no need to explicitly check for
> KVM_STATE_NESTED_SMM_VMXON to determine if it is necessary
> to save nested-state as part of migration stream.
> 
> In addition, destination must enable eVMCS if it is enabled on
> source as specified by the KVM_STATE_NESTED_EVMCS flag, even if
> the VMXON region is not set. Thus, change the code to require saving
> nested-state as part of migration stream in case it is set.
> 
> Reviewed-by: Karl Heubaum <address@hidden>
> Signed-off-by: Liran Alon <address@hidden>
> ---
>  target/i386/machine.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/target/i386/machine.c b/target/i386/machine.c
> index 851b249d1a39..e7d72faf9e24 100644
> --- a/target/i386/machine.c
> +++ b/target/i386/machine.c
> @@ -999,7 +999,7 @@ static bool vmx_nested_state_needed(void *opaque)
>  
>      return ((nested_state->format == KVM_STATE_NESTED_FORMAT_VMX) &&
>              ((nested_state->hdr.vmx.vmxon_pa != -1ull) ||
> -             (nested_state->hdr.vmx.smm.flags & 
> KVM_STATE_NESTED_SMM_VMXON)));
> +             (nested_state->flags & KVM_STATE_NESTED_EVMCS)));
>  }
>  
>  static const VMStateDescription vmstate_vmx_nested_state = {
> 

Queued, thanks.

Paolo