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KVM: PPC: Book3S HV P9: Don't restore PSSCR if not needed

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This also moves the PSSCR update in nested entry to avoid a SPR
scoreboard stall.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211123095231.1036501-42-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2021-11-23 19:52:19 +10:00 committed by Michael Ellerman
parent 9c75f65f35
commit a089a6869e
2 changed files with 24 additions and 9 deletions
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7
arch/powerpc/kvm/book3s_hv.c
View File

@ -3889,7 +3889,9 @@ static int kvmhv_vcpu_entry_p9_nested(struct kvm_vcpu *vcpu, u64 time_limit, uns
if (unlikely(load_vcpu_state(vcpu, &host_os_sprs)))
msr = mfmsr(); /* TM restore can update msr */
mtspr(SPRN_PSSCR_PR, vcpu->arch.psscr);
if (vcpu->arch.psscr != host_psscr)
mtspr(SPRN_PSSCR_PR, vcpu->arch.psscr);
kvmhv_save_hv_regs(vcpu, &hvregs);
hvregs.lpcr = lpcr;
vcpu->arch.regs.msr = vcpu->arch.shregs.msr;
@ -3930,7 +3932,6 @@ static int kvmhv_vcpu_entry_p9_nested(struct kvm_vcpu *vcpu, u64 time_limit, uns
vcpu->arch.shregs.dar = mfspr(SPRN_DAR);
vcpu->arch.shregs.dsisr = mfspr(SPRN_DSISR);
vcpu->arch.psscr = mfspr(SPRN_PSSCR_PR);
mtspr(SPRN_PSSCR_PR, host_psscr);
store_vcpu_state(vcpu);
@ -3943,6 +3944,8 @@ static int kvmhv_vcpu_entry_p9_nested(struct kvm_vcpu *vcpu, u64 time_limit, uns
timer_rearm_host_dec(*tb);
restore_p9_host_os_sprs(vcpu, &host_os_sprs);
if (vcpu->arch.psscr != host_psscr)
mtspr(SPRN_PSSCR_PR, host_psscr);
return trap;
}

26
arch/powerpc/kvm/book3s_hv_p9_entry.c
View File

@ -649,6 +649,7 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc
unsigned long host_dawr0;
unsigned long host_dawrx0;
unsigned long host_psscr;
unsigned long host_hpsscr;
unsigned long host_pidr;
unsigned long host_dawr1;
unsigned long host_dawrx1;
@ -666,7 +667,9 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc
host_hfscr = mfspr(SPRN_HFSCR);
host_ciabr = mfspr(SPRN_CIABR);
host_psscr = mfspr(SPRN_PSSCR);
host_psscr = mfspr(SPRN_PSSCR_PR);
if (cpu_has_feature(CPU_FTR_P9_TM_HV_ASSIST))
host_hpsscr = mfspr(SPRN_PSSCR);
host_pidr = mfspr(SPRN_PID);
if (dawr_enabled()) {
@ -750,8 +753,14 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc
if (vcpu->arch.ciabr != host_ciabr)
mtspr(SPRN_CIABR, vcpu->arch.ciabr);
mtspr(SPRN_PSSCR, vcpu->arch.psscr | PSSCR_EC |
(local_paca->kvm_hstate.fake_suspend << PSSCR_FAKE_SUSPEND_LG));
if (cpu_has_feature(CPU_FTR_P9_TM_HV_ASSIST)) {
mtspr(SPRN_PSSCR, vcpu->arch.psscr | PSSCR_EC |
(local_paca->kvm_hstate.fake_suspend << PSSCR_FAKE_SUSPEND_LG));
} else {
if (vcpu->arch.psscr != host_psscr)
mtspr(SPRN_PSSCR_PR, vcpu->arch.psscr);
}
mtspr(SPRN_HFSCR, vcpu->arch.hfscr);
@ -957,7 +966,7 @@ tm_return_to_guest:
vcpu->arch.ic = mfspr(SPRN_IC);
vcpu->arch.pid = mfspr(SPRN_PID);
vcpu->arch.psscr = mfspr(SPRN_PSSCR) & PSSCR_GUEST_VIS;
vcpu->arch.psscr = mfspr(SPRN_PSSCR_PR);
vcpu->arch.shregs.sprg0 = mfspr(SPRN_SPRG0);
vcpu->arch.shregs.sprg1 = mfspr(SPRN_SPRG1);
@ -1003,9 +1012,12 @@ tm_return_to_guest:
mtspr(SPRN_PURR, local_paca->kvm_hstate.host_purr);
mtspr(SPRN_SPURR, local_paca->kvm_hstate.host_spurr);
/* Preserve PSSCR[FAKE_SUSPEND] until we've called kvmppc_save_tm_hv */
mtspr(SPRN_PSSCR, host_psscr |
(local_paca->kvm_hstate.fake_suspend << PSSCR_FAKE_SUSPEND_LG));
if (cpu_has_feature(CPU_FTR_P9_TM_HV_ASSIST)) {
/* Preserve PSSCR[FAKE_SUSPEND] until we've called kvmppc_save_tm_hv */
mtspr(SPRN_PSSCR, host_hpsscr |
(local_paca->kvm_hstate.fake_suspend << PSSCR_FAKE_SUSPEND_LG));
}
mtspr(SPRN_HFSCR, host_hfscr);
if (vcpu->arch.ciabr != host_ciabr)
mtspr(SPRN_CIABR, host_ciabr);