[PATCH v5 36/48] KVM: PPC: Book3S HV P9: Switch to guest MMU context as late as possible
From: Nicholas Piggin <npiggin@gmail.com>
Date: 2021-04-01 15:20:26
Subsystem:
kernel virtual machine for powerpc (kvm/powerpc), linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
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 <npiggin@gmail.com> --- arch/powerpc/kvm/book3s_hv_interrupt.c | 40 +++++++++++++------------- 1 file changed, 20 insertions(+), 20 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_hv_interrupt.c b/arch/powerpc/kvm/book3s_hv_interrupt.c
index 29e2ae04b8d5..4f3edf68d97b 100644
--- a/arch/powerpc/kvm/book3s_hv_interrupt.c
+++ b/arch/powerpc/kvm/book3s_hv_interrupt.c@@ -149,8 +149,13 @@ 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 = tb + vc->tb_offset; mtspr(SPRN_TBU40, new_tb);
@@ -199,26 +204,6 @@ 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);
@@ -237,6 +222,21 @@ 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);
--
2.23.0