diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2021-11-23 12:52:02 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-11-24 13:08:59 +0300 |
| commit | cb2553a093093ae46cfaee31321bcedcd0312c5d (patch) | |
| tree | 9dd0e5b1fff974bc71773e5786e71454d340abe3 /arch/powerpc/kvm/book3s_hv_p9_entry.c | |
| parent | 6547af3eba88e4806e853fee7547031b2cc6a560 (diff) | |
| download | linux-cb2553a093093ae46cfaee31321bcedcd0312c5d.tar.xz | |
KVM: PPC: Book3S HV P9: Optimise timebase reads
Reduce the number of mfTB executed by passing the current timebase
around entry and exit code rather than read it multiple times.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211123095231.1036501-25-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/kvm/book3s_hv_p9_entry.c')
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv_p9_entry.c | 33 |
1 files changed, 18 insertions, 15 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_p9_entry.c b/arch/powerpc/kvm/book3s_hv_p9_entry.c index e7793bb806eb..2bd96d8256d1 100644 --- a/arch/powerpc/kvm/book3s_hv_p9_entry.c +++ b/arch/powerpc/kvm/book3s_hv_p9_entry.c @@ -183,13 +183,13 @@ static void save_clear_guest_mmu(struct kvm *kvm, struct kvm_vcpu *vcpu) } } -int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpcr) +int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpcr, u64 *tb) { struct kvm *kvm = vcpu->kvm; struct kvm_nested_guest *nested = vcpu->arch.nested; struct kvmppc_vcore *vc = vcpu->arch.vcore; s64 hdec, dec; - u64 tb, purr, spurr; + u64 purr, spurr; u64 *exsave; bool ri_set; int trap; @@ -203,8 +203,7 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc unsigned long host_dawr1; unsigned long host_dawrx1; - tb = mftb(); - hdec = time_limit - tb; + hdec = time_limit - *tb; if (hdec < 0) return BOOK3S_INTERRUPT_HV_DECREMENTER; @@ -230,11 +229,13 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc } if (vc->tb_offset) { - u64 new_tb = tb + 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); + if ((mftb() & 0xffffff) < (new_tb & 0xffffff)) { + new_tb += 0x1000000; + mtspr(SPRN_TBU40, new_tb); + } + *tb = new_tb; vc->tb_offset_applied = vc->tb_offset; } @@ -317,7 +318,7 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc */ mtspr(SPRN_HDEC, hdec); - mtspr(SPRN_DEC, vcpu->arch.dec_expires - tb); + mtspr(SPRN_DEC, vcpu->arch.dec_expires - *tb); #ifdef CONFIG_PPC_TRANSACTIONAL_MEM tm_return_to_guest: @@ -466,15 +467,17 @@ tm_return_to_guest: dec = mfspr(SPRN_DEC); if (!(lpcr & LPCR_LD)) /* Sign extend if not using large decrementer */ dec = (s32) dec; - tb = mftb(); - vcpu->arch.dec_expires = dec + tb; + *tb = mftb(); + vcpu->arch.dec_expires = dec + *tb; if (vc->tb_offset_applied) { - u64 new_tb = tb - 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); + if ((mftb() & 0xffffff) < (new_tb & 0xffffff)) { + new_tb += 0x1000000; + mtspr(SPRN_TBU40, new_tb); + } + *tb = new_tb; vc->tb_offset_applied = 0; } |