Commit a089a686 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

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



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

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211123095231.1036501-42-npiggin@gmail.com
parent 9c75f65f

arch/powerpc/kvm/book3s_hv.c

+5 −2
Original line number Diff line number Diff line
@@ -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 */



	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;

}

arch/powerpc/kvm/book3s_hv_p9_entry.c

+19 −7
Original line number Diff line number Diff line
@@ -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);





	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 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc 


	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 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc 
	mtspr(SPRN_PURR, local_paca->kvm_hstate.host_purr);

	mtspr(SPRN_SPURR, local_paca->kvm_hstate.host_spurr);



	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_psscr |

		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);