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KVM: PPC: Book3S HV P9: Move TB updates

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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: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211123095231.1036501-24-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2021-11-23 19:52:01 +10:00 committed by Michael Ellerman
parent 3c1a4322bb
commit 6547af3eba
1 changed files with 18 additions and 18 deletions
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36
arch/powerpc/kvm/book3s_hv_p9_entry.c
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@ -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 @@ tm_return_to_guest:
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 @@ tm_return_to_guest:
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);