From 41f779917669fcc28a7f5646d1f7a85043c9d152 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Fri, 28 May 2021 19:07:40 +1000 Subject: [PATCH] KVM: PPC: Book3S HV P9: Switch to guest MMU context as late as possible Move MMU context switch as late as reasonably possible to minimise code running with guest context switched in. This becomes more important when this code may run in real-mode, with later changes. Move WARN_ON as early as possible so program check interrupts are less likely to tangle everything up. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210528090752.3542186-21-npiggin@gmail.com --- arch/powerpc/kvm/book3s_hv_p9_entry.c | 40 +++++++++++++++++------------------ 1 file changed, 20 insertions(+), 20 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv_p9_entry.c b/arch/powerpc/kvm/book3s_hv_p9_entry.c index f24a126..0b5bd00 100644 --- a/arch/powerpc/kvm/book3s_hv_p9_entry.c +++ b/arch/powerpc/kvm/book3s_hv_p9_entry.c @@ -138,8 +138,13 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc if (hdec < 0) return BOOK3S_INTERRUPT_HV_DECREMENTER; + WARN_ON_ONCE(vcpu->arch.shregs.msr & MSR_HV); + WARN_ON_ONCE(!(vcpu->arch.shregs.msr & MSR_ME)); + start_timing(vcpu, &vcpu->arch.rm_entry); + vcpu->arch.ceded = 0; + if (vc->tb_offset) { u64 new_tb = mftb() + vc->tb_offset; mtspr(SPRN_TBU40, new_tb); @@ -188,26 +193,6 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc mtspr(SPRN_HFSCR, vcpu->arch.hfscr); - mtspr(SPRN_SPRG0, vcpu->arch.shregs.sprg0); - mtspr(SPRN_SPRG1, vcpu->arch.shregs.sprg1); - mtspr(SPRN_SPRG2, vcpu->arch.shregs.sprg2); - mtspr(SPRN_SPRG3, vcpu->arch.shregs.sprg3); - - mtspr(SPRN_AMOR, ~0UL); - - switch_mmu_to_guest_radix(kvm, vcpu, lpcr); - - /* - * P9 suppresses the HDEC exception when LPCR[HDICE] = 0, - * so set guest LPCR (with HDICE) before writing HDEC. - */ - mtspr(SPRN_HDEC, hdec); - - vcpu->arch.ceded = 0; - - WARN_ON_ONCE(vcpu->arch.shregs.msr & MSR_HV); - WARN_ON_ONCE(!(vcpu->arch.shregs.msr & MSR_ME)); - mtspr(SPRN_HSRR0, vcpu->arch.regs.nip); mtspr(SPRN_HSRR1, (vcpu->arch.shregs.msr & ~MSR_HV) | MSR_ME); @@ -226,6 +211,21 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc */ mtspr(SPRN_HDSISR, HDSISR_CANARY); + mtspr(SPRN_SPRG0, vcpu->arch.shregs.sprg0); + mtspr(SPRN_SPRG1, vcpu->arch.shregs.sprg1); + mtspr(SPRN_SPRG2, vcpu->arch.shregs.sprg2); + mtspr(SPRN_SPRG3, vcpu->arch.shregs.sprg3); + + mtspr(SPRN_AMOR, ~0UL); + + switch_mmu_to_guest_radix(kvm, vcpu, lpcr); + + /* + * P9 suppresses the HDEC exception when LPCR[HDICE] = 0, + * so set guest LPCR (with HDICE) before writing HDEC. + */ + mtspr(SPRN_HDEC, hdec); + __mtmsrd(0, 1); /* clear RI */ mtspr(SPRN_DAR, vcpu->arch.shregs.dar); -- 2.7.4