Commit 6547af3e authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
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KVM: PPC: Book3S HV P9: Move TB updates 



Move the TB updates between saving and loading guest and host SPRs,
to improve scheduling by keeping issue-NTC operations together as
much as possible.

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/20211123095231.1036501-24-npiggin@gmail.com
parent 3c1a4322

arch/powerpc/kvm/book3s_hv_p9_entry.c

+18 −18
Original line number Diff line number Diff line
@@ -215,15 +215,6 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc 


	vcpu->arch.ceded = 0;



	if (vc->tb_offset) {

		u64 new_tb = tb + vc->tb_offset;

		mtspr(SPRN_TBU40, new_tb);

		tb = mftb();

		if ((tb & 0xffffff) < (new_tb & 0xffffff))

			mtspr(SPRN_TBU40, new_tb + 0x1000000);

		vc->tb_offset_applied = vc->tb_offset;

	}



	/* Could avoid mfmsr by passing around, but probably no big deal */

	msr = mfmsr();
@@ -238,6 +229,15 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc 
		host_dawrx1 = mfspr(SPRN_DAWRX1);

	}



	if (vc->tb_offset) {

		u64 new_tb = tb + vc->tb_offset;

		mtspr(SPRN_TBU40, new_tb);

		tb = mftb();

		if ((tb & 0xffffff) < (new_tb & 0xffffff))

			mtspr(SPRN_TBU40, new_tb + 0x1000000);

		vc->tb_offset_applied = vc->tb_offset;

	}



	if (vc->pcr)

		mtspr(SPRN_PCR, vc->pcr | PCR_MASK);

	mtspr(SPRN_DPDES, vc->dpdes);
@@ -469,6 +469,15 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc 
	tb = mftb();

	vcpu->arch.dec_expires = dec + tb;



	if (vc->tb_offset_applied) {

		u64 new_tb = tb - vc->tb_offset_applied;

		mtspr(SPRN_TBU40, new_tb);

		tb = mftb();

		if ((tb & 0xffffff) < (new_tb & 0xffffff))

			mtspr(SPRN_TBU40, new_tb + 0x1000000);

		vc->tb_offset_applied = 0;

	}



	/* 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));
@@ -503,15 +512,6 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc 
	if (vc->pcr)

		mtspr(SPRN_PCR, PCR_MASK);



	if (vc->tb_offset_applied) {

		u64 new_tb = mftb() - vc->tb_offset_applied;

		mtspr(SPRN_TBU40, new_tb);

		tb = mftb();

		if ((tb & 0xffffff) < (new_tb & 0xffffff))

			mtspr(SPRN_TBU40, new_tb + 0x1000000);

		vc->tb_offset_applied = 0;

	}



	/* HDEC must be at least as large as DEC, so decrementer_max fits */

	mtspr(SPRN_HDEC, decrementer_max);