diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2021-11-23 12:52:15 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-11-24 13:09:01 +0300 |
| commit | 022ecb960c89faad42ff0b417a71d9255dd115a3 (patch) | |
| tree | a47d026ae9a2b4d543edc30a283771c4c50b279e /arch/powerpc/kvm/book3s_hv_p9_entry.c | |
| parent | a3e18ca8ab6f7f2260978f0a3842845414d799c0 (diff) | |
| download | linux-022ecb960c89faad42ff0b417a71d9255dd115a3.tar.xz | |
KVM: PPC: Book3S HV P9: Demand fault TM facility registers
Use HFSCR facility disabling to implement demand faulting for TM, with
a hysteresis counter similar to the load_fp etc counters in context
switching that implement the equivalent demand faulting for userspace
facilities.
This speeds up guest entry/exit by avoiding the register save/restore
when a guest is not frequently using them. When a guest does use them
often, there will be some additional demand fault overhead, but these
are not commonly used facilities.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211123095231.1036501-38-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/kvm/book3s_hv_p9_entry.c')
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv_p9_entry.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_p9_entry.c b/arch/powerpc/kvm/book3s_hv_p9_entry.c index 929a7c336b09..8499e8a9ca8f 100644 --- a/arch/powerpc/kvm/book3s_hv_p9_entry.c +++ b/arch/powerpc/kvm/book3s_hv_p9_entry.c @@ -310,7 +310,7 @@ bool load_vcpu_state(struct kvm_vcpu *vcpu, if (MSR_TM_ACTIVE(guest_msr)) { kvmppc_restore_tm_hv(vcpu, guest_msr, true); ret = true; - } else { + } else if (vcpu->arch.hfscr & HFSCR_TM) { mtspr(SPRN_TEXASR, vcpu->arch.texasr); mtspr(SPRN_TFHAR, vcpu->arch.tfhar); mtspr(SPRN_TFIAR, vcpu->arch.tfiar); @@ -346,10 +346,16 @@ void store_vcpu_state(struct kvm_vcpu *vcpu) unsigned long guest_msr = vcpu->arch.shregs.msr; if (MSR_TM_ACTIVE(guest_msr)) { kvmppc_save_tm_hv(vcpu, guest_msr, true); - } else { + } else if (vcpu->arch.hfscr & HFSCR_TM) { vcpu->arch.texasr = mfspr(SPRN_TEXASR); vcpu->arch.tfhar = mfspr(SPRN_TFHAR); vcpu->arch.tfiar = mfspr(SPRN_TFIAR); + + if (!vcpu->arch.nested) { + vcpu->arch.load_tm++; /* see load_ebb comment */ + if (!vcpu->arch.load_tm) + vcpu->arch.hfscr &= ~HFSCR_TM; + } } } #endif @@ -641,8 +647,9 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc msr |= MSR_VEC; if (cpu_has_feature(CPU_FTR_VSX)) msr |= MSR_VSX; - if (cpu_has_feature(CPU_FTR_TM) || - cpu_has_feature(CPU_FTR_P9_TM_HV_ASSIST)) + if ((cpu_has_feature(CPU_FTR_TM) || + cpu_has_feature(CPU_FTR_P9_TM_HV_ASSIST)) && + (vcpu->arch.hfscr & HFSCR_TM)) msr |= MSR_TM; msr = msr_check_and_set(msr); /* Save MSR for restore. This is after hard disable, so EE is clear. */ |