On Thu, Nov 23, 2017 at 03:36:18PM +1100, Benjamin Herrenschmidt wrote:
> This stores the MMU mode (real vs. virt) in the PACA on exceptions
> that do a KVM test.
>
> At the moment, we do this unconditionally in those exceptions due
> to how the macro system is put together. In the future we could
> find a way to only do it when actually exiting a guest.
>
> This will avoid a pile of mfmsr in the KVM exit path
Comments below...
> diff --git a/arch/powerpc/include/asm/kvm_book3s_asm.h b/arch/powerpc/include/asm/kvm_book3s_asm.h
> index 83596f32f50b..7775a278e56e 100644
> --- a/arch/powerpc/include/asm/kvm_book3s_asm.h
> +++ b/arch/powerpc/include/asm/kvm_book3s_asm.h
> @@ -118,6 +118,7 @@ struct kvmppc_host_state {
> void __iomem *xive_tima_phys;
> void __iomem *xive_tima_virt;
> u32 saved_xirr;
> + u8 exit_virt; /* MMU mode on exception exit */
This is being added in the #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
section of this struct, but as far as I can see we will need the new
field in the case where only PR and not HV is configured. Did you try
compiling a PR-only config?
Paul.
