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KVM: PPC: Book3S HV P9: Implement TM fastpath for guest entry/exit

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If TM is not active, only TM register state needs to be saved and
restored, avoiding several mfmsr/mtmsrd instructions and improving
performance.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211123095231.1036501-33-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2021-11-23 19:52:10 +10:00 committed by Michael Ellerman
parent d5f4801945
commit 3f9e2966d1
1 changed files with 23 additions and 4 deletions
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27
arch/powerpc/kvm/book3s_hv_p9_entry.c
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@ -287,11 +287,20 @@ bool load_vcpu_state(struct kvm_vcpu *vcpu,
{
bool ret = false;
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
if (cpu_has_feature(CPU_FTR_TM) ||
cpu_has_feature(CPU_FTR_P9_TM_HV_ASSIST)) {
kvmppc_restore_tm_hv(vcpu, vcpu->arch.shregs.msr, true);
ret = true;
unsigned long guest_msr = vcpu->arch.shregs.msr;
if (MSR_TM_ACTIVE(guest_msr)) {
kvmppc_restore_tm_hv(vcpu, guest_msr, true);
ret = true;
} else {
mtspr(SPRN_TEXASR, vcpu->arch.texasr);
mtspr(SPRN_TFHAR, vcpu->arch.tfhar);
mtspr(SPRN_TFIAR, vcpu->arch.tfiar);
}
}
#endif
load_spr_state(vcpu, host_os_sprs);
@ -315,9 +324,19 @@ void store_vcpu_state(struct kvm_vcpu *vcpu)
#endif
vcpu->arch.vrsave = mfspr(SPRN_VRSAVE);
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
if (cpu_has_feature(CPU_FTR_TM) ||
cpu_has_feature(CPU_FTR_P9_TM_HV_ASSIST))
kvmppc_save_tm_hv(vcpu, vcpu->arch.shregs.msr, true);
cpu_has_feature(CPU_FTR_P9_TM_HV_ASSIST)) {
unsigned long guest_msr = vcpu->arch.shregs.msr;
if (MSR_TM_ACTIVE(guest_msr)) {
kvmppc_save_tm_hv(vcpu, guest_msr, true);
} else {
vcpu->arch.texasr = mfspr(SPRN_TEXASR);
vcpu->arch.tfhar = mfspr(SPRN_TFHAR);
vcpu->arch.tfiar = mfspr(SPRN_TFIAR);
}
}
#endif
}
EXPORT_SYMBOL_GPL(store_vcpu_state);