Excerpts from Nicholas Piggin's message of May 23, 2021 10:21 pm:
> Similar to commit 25edcc50d76c ("KVM: PPC: Book3S HV: Save and restore
> FSCR in the P9 path"), ensure the P7/8 path saves and restores the host
> FSCR. The logic explained in that patch actually applies there to the
> old path well: a context switch can be made before kvmppc_vcpu_run_hv
> restores the host FSCR and returns.
>
> Fixes: b005255e12a3 ("KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs")
> Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
> ---
> arch/powerpc/kvm/book3s_hv_rmhandlers.S | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
> index 5e634db4809b..2b98e710c7a1 100644
> --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
> +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
> @@ -44,7 +44,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
> #define NAPPING_UNSPLIT 3
>
> /* Stack frame offsets for kvmppc_hv_entry */
> -#define SFS 208
> +#define SFS 216
> #define STACK_SLOT_TRAP (SFS-4)
> #define STACK_SLOT_SHORT_PATH (SFS-8)
> #define STACK_SLOT_TID (SFS-16)
> @@ -59,8 +59,9 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
> #define STACK_SLOT_UAMOR (SFS-88)
> #define STACK_SLOT_DAWR1 (SFS-96)
> #define STACK_SLOT_DAWRX1 (SFS-104)
> +#define STACK_SLOT_FSCR (SFS-112)
> /* the following is used by the P9 short path */
> -#define STACK_SLOT_NVGPRS (SFS-152) /* 18 gprs */
> +#define STACK_SLOT_NVGPRS (SFS-160) /* 18 gprs */
Actually, hmm.. this is wrong because nvgprs are subtracted from
this offset. But then I can't work out why 95a6432ce9038 raised
SFS from 160 to 208.
Thanks,
Nick
