Re: [PATCH v3 02/52] powerpc/64s: guard optional TIDR SPR with CPU ftr test
From: Fabiano Rosas <hidden>
Date: 2021-10-11 18:45:40
Nicholas Piggin [off-list ref] writes:
The TIDR SPR only exists on POWER9. Avoid accessing it when the feature bit for it is not set.
Not related to this patch, but how does this work with compat mode? A P9 compat mode guest would get an invalid instruction when trying to access this SPR?
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Fabiano Rosas <redacted>
quoted hunk ↗ jump to hunk
--- arch/powerpc/kvm/book3s_hv.c | 12 ++++++++---- arch/powerpc/xmon/xmon.c | 10 ++++++++-- 2 files changed, 16 insertions(+), 6 deletions(-)diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 2acb1c96cfaf..f4a779fffd18 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c@@ -3767,7 +3767,8 @@ static void load_spr_state(struct kvm_vcpu *vcpu) mtspr(SPRN_EBBHR, vcpu->arch.ebbhr); mtspr(SPRN_EBBRR, vcpu->arch.ebbrr); mtspr(SPRN_BESCR, vcpu->arch.bescr); - mtspr(SPRN_TIDR, vcpu->arch.tid); + if (cpu_has_feature(CPU_FTR_P9_TIDR)) + mtspr(SPRN_TIDR, vcpu->arch.tid); mtspr(SPRN_AMR, vcpu->arch.amr); mtspr(SPRN_UAMOR, vcpu->arch.uamor);@@ -3793,7 +3794,8 @@ static void store_spr_state(struct kvm_vcpu *vcpu) vcpu->arch.ebbhr = mfspr(SPRN_EBBHR); vcpu->arch.ebbrr = mfspr(SPRN_EBBRR); vcpu->arch.bescr = mfspr(SPRN_BESCR); - vcpu->arch.tid = mfspr(SPRN_TIDR); + if (cpu_has_feature(CPU_FTR_P9_TIDR)) + vcpu->arch.tid = mfspr(SPRN_TIDR); vcpu->arch.amr = mfspr(SPRN_AMR); vcpu->arch.uamor = mfspr(SPRN_UAMOR); vcpu->arch.dscr = mfspr(SPRN_DSCR);@@ -3813,7 +3815,8 @@ struct p9_host_os_sprs { static void save_p9_host_os_sprs(struct p9_host_os_sprs *host_os_sprs) { host_os_sprs->dscr = mfspr(SPRN_DSCR); - host_os_sprs->tidr = mfspr(SPRN_TIDR); + if (cpu_has_feature(CPU_FTR_P9_TIDR)) + host_os_sprs->tidr = mfspr(SPRN_TIDR); host_os_sprs->iamr = mfspr(SPRN_IAMR); host_os_sprs->amr = mfspr(SPRN_AMR); host_os_sprs->fscr = mfspr(SPRN_FSCR);@@ -3827,7 +3830,8 @@ static void restore_p9_host_os_sprs(struct kvm_vcpu *vcpu, mtspr(SPRN_UAMOR, 0); mtspr(SPRN_DSCR, host_os_sprs->dscr); - mtspr(SPRN_TIDR, host_os_sprs->tidr); + if (cpu_has_feature(CPU_FTR_P9_TIDR)) + mtspr(SPRN_TIDR, host_os_sprs->tidr); mtspr(SPRN_IAMR, host_os_sprs->iamr); if (host_os_sprs->amr != vcpu->arch.amr)diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index dd8241c009e5..7958e5aae844 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c@@ -2107,8 +2107,14 @@ static void dump_300_sprs(void) if (!cpu_has_feature(CPU_FTR_ARCH_300)) return; - printf("pidr = %.16lx tidr = %.16lx\n", - mfspr(SPRN_PID), mfspr(SPRN_TIDR)); + if (cpu_has_feature(CPU_FTR_P9_TIDR)) { + printf("pidr = %.16lx tidr = %.16lx\n", + mfspr(SPRN_PID), mfspr(SPRN_TIDR)); + } else { + printf("pidr = %.16lx\n", + mfspr(SPRN_PID)); + } + printf("psscr = %.16lx\n", hv ? mfspr(SPRN_PSSCR) : mfspr(SPRN_PSSCR_PR));