[PATCH 20/26] KVM: PPC: Book3S PR: enable NV reg restore for reading TM SPR at guest privilege state

[Paul Mackerras]

On Thu, Jan 11, 2018 at 06:11:33PM +0800, wei.guo.simon at gmail.com wrote:
> From: Simon Guo <wei.guo.simon at gmail.com>
> 
> Currently kvmppc_handle_fac() will not update NV GPRs and thus it can
> return with GUEST_RESUME.
> 
> However PR KVM guest always disables MSR_TM bit at privilege state. If PR
> privilege guest are trying to read TM SPRs, it will trigger TM facility
> unavailable exception and fall into kvmppc_handle_fac(). Then the emulation
> will be done by kvmppc_core_emulate_mfspr_pr(). The mfspr instruction can
> include a RT with NV reg. So it is necessary to restore NV GPRs at this
> case, to reflect the update to NV RT.
> 
> This patch make kvmppc_handle_fac() return GUEST_RESUME_NV at TM fac
> exception and with guest privilege state.
> 
> Signed-off-by: Simon Guo <wei.guo.simon at gmail.com>

Reviewed-by: Paul Mackerras <paulus at ozlabs.org>