diff options
| author | Nicholas Piggin | 2021-11-23 19:52:24 +1000 |
|---|---|---|
| committer | Michael Ellerman | 2021-11-24 21:09:02 +1100 |
| commit | 241d1f19f0e5c257881a0661f201b51dc3e57f8c (patch) | |
| tree | 5d63136f9c86a397037e13b55ccf2837267e6593 | |
| parent | b49c65c5f9f1dac4ef1764578ad55bacf526eb38 (diff) | |
KVM: PPC: Book3S HV P9: Optimise hash guest SLB saving
slbmfee/slbmfev instructions are very expensive, moreso than a regular
mfspr instruction, so minimising them significantly improves hash guest
exit performance. The slbmfev is only required if slbmfee found a valid
SLB entry.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211123095231.1036501-47-npiggin@gmail.com
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv_p9_entry.c | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_p9_entry.c b/arch/powerpc/kvm/book3s_hv_p9_entry.c index d123813296ba..8fa48ba01f79 100644 --- a/arch/powerpc/kvm/book3s_hv_p9_entry.c +++ b/arch/powerpc/kvm/book3s_hv_p9_entry.c @@ -487,10 +487,22 @@ static void __accumulate_time(struct kvm_vcpu *vcpu, struct kvmhv_tb_accumulator #define accumulate_time(vcpu, next) do {} while (0) #endif -static inline void mfslb(unsigned int idx, u64 *slbee, u64 *slbev) +static inline u64 mfslbv(unsigned int idx) { - asm volatile("slbmfev %0,%1" : "=r" (*slbev) : "r" (idx)); - asm volatile("slbmfee %0,%1" : "=r" (*slbee) : "r" (idx)); + u64 slbev; + + asm volatile("slbmfev %0,%1" : "=r" (slbev) : "r" (idx)); + + return slbev; +} + +static inline u64 mfslbe(unsigned int idx) +{ + u64 slbee; + + asm volatile("slbmfee %0,%1" : "=r" (slbee) : "r" (idx)); + + return slbee; } static inline void mtslb(u64 slbee, u64 slbev) @@ -620,8 +632,10 @@ static void save_clear_guest_mmu(struct kvm *kvm, struct kvm_vcpu *vcpu) */ for (i = 0; i < vcpu->arch.slb_nr; i++) { u64 slbee, slbev; - mfslb(i, &slbee, &slbev); + + slbee = mfslbe(i); if (slbee & SLB_ESID_V) { + slbev = mfslbv(i); vcpu->arch.slb[nr].orige = slbee | i; vcpu->arch.slb[nr].origv = slbev; nr++; |