On Mon, Oct 08, 2018 at 04:30:55PM +1100, Paul Mackerras wrote: > This creates an alternative guest entry/exit path which is used for > radix guests on POWER9 systems when we have indep_threads_mode=Y. In > these circumstances there is exactly one vcpu per vcore and there is > no coordination required between vcpus or vcores; the vcpu can enter > the guest without needing to synchronize with anything else. > > The new fast path is implemented almost entirely in C in book3s_hv.c > and runs with the MMU on until the guest is entered. On guest exit > we use the existing path until the point where we are committed to > exiting the guest (as distinct from handling an interrupt in the > low-level code and returning to the guest) and we have pulled the > guest context from the XIVE. At that point we check a flag in the > stack frame to see whether we came in via the old path and the new > path; if we came in via the new path then we go back to C code to do > the rest of the process of saving the guest context and restoring the > host context. > > The C code is split into separate functions for handling the > OS-accessible state and the hypervisor state, with the idea that the > latter can be replaced by a hypercall when we implement nested > virtualization. > > Signed-off-by: Paul Mackerras <pau...@ozlabs.org>
Reviewed-by: David Gibson <da...@gibson.dropbear.id.au>
> ---
> arch/powerpc/include/asm/asm-prototypes.h | 2 +
> arch/powerpc/include/asm/kvm_ppc.h | 2 +
> arch/powerpc/kvm/book3s_hv.c | 429
> +++++++++++++++++++++++++++++-
> arch/powerpc/kvm/book3s_hv_ras.c | 2 +
> arch/powerpc/kvm/book3s_hv_rmhandlers.S | 95 ++++++-
> arch/powerpc/kvm/book3s_xive.c | 63 +++++
> 6 files changed, 589 insertions(+), 4 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/asm-prototypes.h
> b/arch/powerpc/include/asm/asm-prototypes.h
> index 0c1a2b0..5c9b00c 100644
> --- a/arch/powerpc/include/asm/asm-prototypes.h
> +++ b/arch/powerpc/include/asm/asm-prototypes.h
> @@ -165,4 +165,6 @@ void kvmhv_load_host_pmu(void);
> void kvmhv_save_guest_pmu(struct kvm_vcpu *vcpu, bool pmu_in_use);
> void kvmhv_load_guest_pmu(struct kvm_vcpu *vcpu);
>
> +int __kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu);
> +
> #endif /* _ASM_POWERPC_ASM_PROTOTYPES_H */
> diff --git a/arch/powerpc/include/asm/kvm_ppc.h
> b/arch/powerpc/include/asm/kvm_ppc.h
> index 83d61b8..245e564 100644
> --- a/arch/powerpc/include/asm/kvm_ppc.h
> +++ b/arch/powerpc/include/asm/kvm_ppc.h
> @@ -585,6 +585,7 @@ extern int kvmppc_xive_set_icp(struct kvm_vcpu *vcpu, u64
> icpval);
>
> extern int kvmppc_xive_set_irq(struct kvm *kvm, int irq_source_id, u32 irq,
> int level, bool line_status);
> +extern void kvmppc_xive_push_vcpu(struct kvm_vcpu *vcpu);
> #else
> static inline int kvmppc_xive_set_xive(struct kvm *kvm, u32 irq, u32 server,
> u32 priority) { return -1; }
> @@ -607,6 +608,7 @@ static inline int kvmppc_xive_set_icp(struct kvm_vcpu
> *vcpu, u64 icpval) { retur
>
> static inline int kvmppc_xive_set_irq(struct kvm *kvm, int irq_source_id,
> u32 irq,
> int level, bool line_status) { return
> -ENODEV; }
> +static inline void kvmppc_xive_push_vcpu(struct kvm_vcpu *vcpu) { }
> #endif /* CONFIG_KVM_XIVE */
>
> /*
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 0e17593..0c1dd76 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -3080,6 +3080,269 @@ static noinline void kvmppc_run_core(struct
> kvmppc_vcore *vc)
> }
>
> /*
> + * Load up hypervisor-mode registers on P9.
> + */
> +static int kvmhv_load_hv_regs_and_go(struct kvm_vcpu *vcpu, u64 time_limit)
> +{
> + struct kvmppc_vcore *vc = vcpu->arch.vcore;
> + s64 hdec;
> + u64 tb, purr, spurr;
> + int trap;
> + unsigned long host_hfscr = mfspr(SPRN_HFSCR);
> + unsigned long host_ciabr = mfspr(SPRN_CIABR);
> + unsigned long host_dawr = mfspr(SPRN_DAWR);
> + unsigned long host_dawrx = mfspr(SPRN_DAWRX);
> + unsigned long host_psscr = mfspr(SPRN_PSSCR);
> + unsigned long host_pidr = mfspr(SPRN_PID);
> +
> + hdec = time_limit - mftb();
> + if (hdec < 0)
> + return BOOK3S_INTERRUPT_HV_DECREMENTER;
> + mtspr(SPRN_HDEC, hdec);
> +
> + if (vc->tb_offset) {
> + u64 new_tb = mftb() + 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);
> + mtspr(SPRN_DPDES, vc->dpdes);
> + mtspr(SPRN_VTB, vc->vtb);
> +
> + local_paca->kvm_hstate.host_purr = mfspr(SPRN_PURR);
> + local_paca->kvm_hstate.host_spurr = mfspr(SPRN_SPURR);
> + mtspr(SPRN_PURR, vcpu->arch.purr);
> + mtspr(SPRN_SPURR, vcpu->arch.spurr);
> +
> + if (cpu_has_feature(CPU_FTR_DAWR)) {
> + mtspr(SPRN_DAWR, vcpu->arch.dawr);
> + mtspr(SPRN_DAWRX, vcpu->arch.dawrx);
> + }
> + mtspr(SPRN_CIABR, vcpu->arch.ciabr);
> + mtspr(SPRN_IC, vcpu->arch.ic);
> + mtspr(SPRN_PID, vcpu->arch.pid);
> +
> + mtspr(SPRN_PSSCR, vcpu->arch.psscr | PSSCR_EC |
> + (local_paca->kvm_hstate.fake_suspend << PSSCR_FAKE_SUSPEND_LG));
> +
> + 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);
> +
> + mtspr(SPRN_LPCR, vc->lpcr);
> + isync();
> +
> + kvmppc_xive_push_vcpu(vcpu);
> +
> + mtspr(SPRN_SRR0, vcpu->arch.shregs.srr0);
> + mtspr(SPRN_SRR1, vcpu->arch.shregs.srr1);
> +
> + trap = __kvmhv_vcpu_entry_p9(vcpu);
> +
> + /* Advance host PURR/SPURR by the amount used by guest */
> + purr = mfspr(SPRN_PURR);
> + spurr = mfspr(SPRN_SPURR);
> + mtspr(SPRN_PURR, local_paca->kvm_hstate.host_purr +
> + purr - vcpu->arch.purr);
> + mtspr(SPRN_SPURR, local_paca->kvm_hstate.host_spurr +
> + spurr - vcpu->arch.spurr);
> + vcpu->arch.purr = purr;
> + vcpu->arch.spurr = spurr;
> +
> + vcpu->arch.ic = mfspr(SPRN_IC);
> + vcpu->arch.pid = mfspr(SPRN_PID);
> + vcpu->arch.psscr = mfspr(SPRN_PSSCR) & PSSCR_GUEST_VIS;
> +
> + vcpu->arch.shregs.sprg0 = mfspr(SPRN_SPRG0);
> + vcpu->arch.shregs.sprg1 = mfspr(SPRN_SPRG1);
> + vcpu->arch.shregs.sprg2 = mfspr(SPRN_SPRG2);
> + vcpu->arch.shregs.sprg3 = mfspr(SPRN_SPRG3);
> +
> + mtspr(SPRN_PSSCR, host_psscr);
> + mtspr(SPRN_HFSCR, host_hfscr);
> + mtspr(SPRN_CIABR, host_ciabr);
> + mtspr(SPRN_DAWR, host_dawr);
> + mtspr(SPRN_DAWRX, host_dawrx);
> + mtspr(SPRN_PID, host_pidr);
> +
> + /*
> + * Since this is radix, do a eieio; tlbsync; ptesync sequence in
> + * case we interrupted the guest between a tlbie and a ptesync.
> + */
> + asm volatile("eieio; tlbsync; ptesync");
> +
> + mtspr(SPRN_LPID, vcpu->kvm->arch.host_lpid); /* restore host LPID */
> + isync();
> +
> + vc->dpdes = mfspr(SPRN_DPDES);
> + vc->vtb = mfspr(SPRN_VTB);
> + mtspr(SPRN_DPDES, 0);
> + if (vc->pcr)
> + mtspr(SPRN_PCR, 0);
> +
> + 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;
> + }
> +
> + mtspr(SPRN_HDEC, 0x7fffffff);
> + mtspr(SPRN_LPCR, vcpu->kvm->arch.host_lpcr);
> +
> + return trap;
> +}
> +
> +/*
> + * Virtual-mode guest entry for POWER9 and later when the host and
> + * guest are both using the radix MMU. The LPIDR has already been set.
> + */
> +int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit)
> +{
> + struct kvmppc_vcore *vc = vcpu->arch.vcore;
> + unsigned long host_dscr = mfspr(SPRN_DSCR);
> + unsigned long host_tidr = mfspr(SPRN_TIDR);
> + unsigned long host_iamr = mfspr(SPRN_IAMR);
> + s64 dec;
> + u64 tb;
> + int trap, save_pmu;
> +
> + dec = mfspr(SPRN_DEC);
> + tb = mftb();
> + if (dec < 512)
> + return BOOK3S_INTERRUPT_HV_DECREMENTER;
> + local_paca->kvm_hstate.dec_expires = dec + tb;
> + if (local_paca->kvm_hstate.dec_expires < time_limit)
> + time_limit = local_paca->kvm_hstate.dec_expires;
> +
> + vcpu->arch.ceded = 0;
> +
> + kvmhv_save_host_pmu(); /* saves it to PACA kvm_hstate */
> +
> + kvmppc_subcore_enter_guest();
> +
> + vc->entry_exit_map = 1;
> + vc->in_guest = 1;
> +
> + if (vcpu->arch.vpa.pinned_addr) {
> + struct lppaca *lp = vcpu->arch.vpa.pinned_addr;
> + u32 yield_count = be32_to_cpu(lp->yield_count) + 1;
> + lp->yield_count = cpu_to_be32(yield_count);
> + vcpu->arch.vpa.dirty = 1;
> + }
> +
> + if (cpu_has_feature(CPU_FTR_TM) ||
> + cpu_has_feature(CPU_FTR_P9_TM_HV_ASSIST))
> + kvmppc_restore_tm_hv(vcpu, vcpu->arch.shregs.msr, true);
> +
> + kvmhv_load_guest_pmu(vcpu);
> +
> + msr_check_and_set(MSR_FP | MSR_VEC | MSR_VSX);
> + load_fp_state(&vcpu->arch.fp);
> + load_vr_state(&vcpu->arch.vr);
> +
> + mtspr(SPRN_DSCR, vcpu->arch.dscr);
> + mtspr(SPRN_IAMR, vcpu->arch.iamr);
> + mtspr(SPRN_PSPB, vcpu->arch.pspb);
> + mtspr(SPRN_FSCR, vcpu->arch.fscr);
> + mtspr(SPRN_TAR, vcpu->arch.tar);
> + mtspr(SPRN_EBBHR, vcpu->arch.ebbhr);
> + mtspr(SPRN_EBBRR, vcpu->arch.ebbrr);
> + mtspr(SPRN_BESCR, vcpu->arch.bescr);
> + mtspr(SPRN_WORT, vcpu->arch.wort);
> + mtspr(SPRN_TIDR, vcpu->arch.tid);
> + mtspr(SPRN_DAR, vcpu->arch.shregs.dar);
> + mtspr(SPRN_DSISR, vcpu->arch.shregs.dsisr);
> + mtspr(SPRN_AMR, vcpu->arch.amr);
> + mtspr(SPRN_UAMOR, vcpu->arch.uamor);
> +
> + if (!(vcpu->arch.ctrl & 1))
> + mtspr(SPRN_CTRLT, mfspr(SPRN_CTRLF) & ~1);
> +
> + mtspr(SPRN_DEC, vcpu->arch.dec_expires - mftb());
> +
> + if (vcpu->arch.doorbell_request) {
> + vc->dpdes = 1;
> + smp_wmb();
> + vcpu->arch.doorbell_request = 0;
> + }
> +
> + trap = kvmhv_load_hv_regs_and_go(vcpu, time_limit);
> +
> + vcpu->arch.slb_max = 0;
> + dec = mfspr(SPRN_DEC);
> + tb = mftb();
> + vcpu->arch.dec_expires = dec + tb;
> + vcpu->cpu = -1;
> + vcpu->arch.thread_cpu = -1;
> + vcpu->arch.ctrl = mfspr(SPRN_CTRLF);
> +
> + vcpu->arch.iamr = mfspr(SPRN_IAMR);
> + vcpu->arch.pspb = mfspr(SPRN_PSPB);
> + vcpu->arch.fscr = mfspr(SPRN_FSCR);
> + vcpu->arch.tar = mfspr(SPRN_TAR);
> + vcpu->arch.ebbhr = mfspr(SPRN_EBBHR);
> + vcpu->arch.ebbrr = mfspr(SPRN_EBBRR);
> + vcpu->arch.bescr = mfspr(SPRN_BESCR);
> + vcpu->arch.wort = mfspr(SPRN_WORT);
> + vcpu->arch.tid = mfspr(SPRN_TIDR);
> + vcpu->arch.amr = mfspr(SPRN_AMR);
> + vcpu->arch.uamor = mfspr(SPRN_UAMOR);
> + vcpu->arch.dscr = mfspr(SPRN_DSCR);
> +
> + mtspr(SPRN_PSPB, 0);
> + mtspr(SPRN_WORT, 0);
> + mtspr(SPRN_AMR, 0);
> + mtspr(SPRN_UAMOR, 0);
> + mtspr(SPRN_DSCR, host_dscr);
> + mtspr(SPRN_TIDR, host_tidr);
> + mtspr(SPRN_IAMR, host_iamr);
> + mtspr(SPRN_PSPB, 0);
> +
> + msr_check_and_set(MSR_FP | MSR_VEC | MSR_VSX);
> + store_fp_state(&vcpu->arch.fp);
> + store_vr_state(&vcpu->arch.vr);
> +
> + if (cpu_has_feature(CPU_FTR_TM) ||
> + cpu_has_feature(CPU_FTR_P9_TM_HV_ASSIST))
> + kvmppc_save_tm_hv(vcpu, vcpu->arch.shregs.msr, true);
> +
> + save_pmu = 1;
> + if (vcpu->arch.vpa.pinned_addr) {
> + struct lppaca *lp = vcpu->arch.vpa.pinned_addr;
> + u32 yield_count = be32_to_cpu(lp->yield_count) + 1;
> + lp->yield_count = cpu_to_be32(yield_count);
> + vcpu->arch.vpa.dirty = 1;
> + save_pmu = lp->pmcregs_in_use;
> + }
> +
> + kvmhv_save_guest_pmu(vcpu, save_pmu);
> +
> + vc->entry_exit_map = 0x101;
> + vc->in_guest = 0;
> +
> + mtspr(SPRN_DEC, local_paca->kvm_hstate.dec_expires - mftb());
> +
> + kvmhv_load_host_pmu();
> +
> + kvmppc_subcore_exit_guest();
> +
> + return trap;
> +}
> +
> +/*
> * Wait for some other vcpu thread to execute us, and
> * wake us up when we need to handle something in the host.
> */
> @@ -3405,6 +3668,167 @@ static int kvmppc_run_vcpu(struct kvm_run *kvm_run,
> struct kvm_vcpu *vcpu)
> return vcpu->arch.ret;
> }
>
> +static int kvmhv_run_single_vcpu(struct kvm_run *kvm_run,
> + struct kvm_vcpu *vcpu, u64 time_limit)
> +{
> + int trap, r, pcpu, pcpu0;
> + int srcu_idx;
> + struct kvmppc_vcore *vc;
> + struct kvm *kvm = vcpu->kvm;
> +
> + trace_kvmppc_run_vcpu_enter(vcpu);
> +
> + kvm_run->exit_reason = 0;
> + vcpu->arch.ret = RESUME_GUEST;
> + vcpu->arch.trap = 0;
> +
> + vc = vcpu->arch.vcore;
> + vcpu->arch.ceded = 0;
> + vcpu->arch.run_task = current;
> + vcpu->arch.kvm_run = kvm_run;
> + vcpu->arch.stolen_logged = vcore_stolen_time(vc, mftb());
> + vcpu->arch.state = KVMPPC_VCPU_RUNNABLE;
> + vcpu->arch.busy_preempt = TB_NIL;
> + vcpu->arch.last_inst = KVM_INST_FETCH_FAILED;
> + vc->runnable_threads[0] = vcpu;
> + vc->n_runnable = 1;
> + vc->runner = vcpu;
> +
> + /* See if the MMU is ready to go */
> + if (!kvm->arch.mmu_ready) {
> + r = kvmhv_setup_mmu(vcpu);
> + if (r) {
> + kvm_run->exit_reason = KVM_EXIT_FAIL_ENTRY;
> + kvm_run->fail_entry.
> + hardware_entry_failure_reason = 0;
> + vcpu->arch.ret = r;
> + goto out;
> + }
> + }
> +
> + if (need_resched())
> + cond_resched();
> +
> + kvmppc_update_vpas(vcpu);
> +
> + init_vcore_to_run(vc);
> + vc->preempt_tb = TB_NIL;
> +
> + preempt_disable();
> + pcpu = smp_processor_id();
> + vc->pcpu = pcpu;
> + kvmppc_prepare_radix_vcpu(vcpu, pcpu);
> +
> + local_irq_disable();
> + hard_irq_disable();
> + if (signal_pending(current))
> + goto sigpend;
> + if (lazy_irq_pending() || need_resched() || !kvm->arch.mmu_ready)
> + goto out;
> +
> + kvmppc_core_prepare_to_enter(vcpu);
> +
> + kvmppc_clear_host_core(pcpu);
> +
> + local_paca->kvm_hstate.tid = 0;
> + local_paca->kvm_hstate.napping = 0;
> + local_paca->kvm_hstate.kvm_split_mode = NULL;
> + kvmppc_start_thread(vcpu, vc);
> + kvmppc_create_dtl_entry(vcpu, vc);
> + trace_kvm_guest_enter(vcpu);
> +
> + vc->vcore_state = VCORE_RUNNING;
> + trace_kvmppc_run_core(vc, 0);
> +
> + mtspr(SPRN_LPID, vc->kvm->arch.lpid);
> + isync();
> +
> + /* See comment above in kvmppc_run_core() about this */
> + pcpu0 = pcpu;
> + if (cpu_has_feature(CPU_FTR_ARCH_300))
> + pcpu0 &= ~0x3UL;
> +
> + if (cpumask_test_cpu(pcpu0, &kvm->arch.need_tlb_flush)) {
> + radix__local_flush_tlb_lpid_guest(kvm->arch.lpid);
> + /* Clear the bit after the TLB flush */
> + cpumask_clear_cpu(pcpu0, &kvm->arch.need_tlb_flush);
> + }
> +
> + trace_hardirqs_on();
> + guest_enter_irqoff();
> +
> + srcu_idx = srcu_read_lock(&kvm->srcu);
> +
> + this_cpu_disable_ftrace();
> +
> + trap = kvmhv_p9_guest_entry(vcpu, time_limit);
> + vcpu->arch.trap = trap;
> +
> + this_cpu_enable_ftrace();
> +
> + srcu_read_unlock(&kvm->srcu, srcu_idx);
> +
> + mtspr(SPRN_LPID, kvm->arch.host_lpid);
> + isync();
> +
> + trace_hardirqs_off();
> + set_irq_happened(trap);
> +
> + kvmppc_set_host_core(pcpu);
> +
> + local_irq_enable();
> + guest_exit();
> +
> + cpumask_clear_cpu(pcpu, &kvm->arch.cpu_in_guest);
> +
> + preempt_enable();
> +
> + /* cancel pending decrementer exception if DEC is now positive */
> + if (get_tb() < vcpu->arch.dec_expires && kvmppc_core_pending_dec(vcpu))
> + kvmppc_core_dequeue_dec(vcpu);
> +
> + trace_kvm_guest_exit(vcpu);
> + r = RESUME_GUEST;
> + if (trap)
> + r = kvmppc_handle_exit_hv(kvm_run, vcpu, current);
> + vcpu->arch.ret = r;
> +
> + if (is_kvmppc_resume_guest(r) && vcpu->arch.ceded &&
> + !kvmppc_vcpu_woken(vcpu)) {
> + kvmppc_set_timer(vcpu);
> + while (vcpu->arch.ceded && !kvmppc_vcpu_woken(vcpu)) {
> + if (signal_pending(current)) {
> + vcpu->stat.signal_exits++;
> + kvm_run->exit_reason = KVM_EXIT_INTR;
> + vcpu->arch.ret = -EINTR;
> + break;
> + }
> + spin_lock(&vc->lock);
> + kvmppc_vcore_blocked(vc);
> + spin_unlock(&vc->lock);
> + }
> + }
> + vcpu->arch.ceded = 0;
> +
> + vc->vcore_state = VCORE_INACTIVE;
> + trace_kvmppc_run_core(vc, 1);
> +
> + done:
> + kvmppc_remove_runnable(vc, vcpu);
> + trace_kvmppc_run_vcpu_exit(vcpu, kvm_run);
> +
> + return vcpu->arch.ret;
> +
> + sigpend:
> + vcpu->stat.signal_exits++;
> + kvm_run->exit_reason = KVM_EXIT_INTR;
> + vcpu->arch.ret = -EINTR;
> + out:
> + local_irq_enable();
> + preempt_enable();
> + goto done;
> +}
> +
> static int kvmppc_vcpu_run_hv(struct kvm_run *run, struct kvm_vcpu *vcpu)
> {
> int r;
> @@ -3480,7 +3904,10 @@ static int kvmppc_vcpu_run_hv(struct kvm_run *run,
> struct kvm_vcpu *vcpu)
> vcpu->arch.state = KVMPPC_VCPU_BUSY_IN_HOST;
>
> do {
> - r = kvmppc_run_vcpu(run, vcpu);
> + if (kvm->arch.threads_indep && kvm_is_radix(kvm))
> + r = kvmhv_run_single_vcpu(run, vcpu, ~(u64)0);
> + else
> + r = kvmppc_run_vcpu(run, vcpu);
>
> if (run->exit_reason == KVM_EXIT_PAPR_HCALL &&
> !(vcpu->arch.shregs.msr & MSR_PR)) {
> diff --git a/arch/powerpc/kvm/book3s_hv_ras.c
> b/arch/powerpc/kvm/book3s_hv_ras.c
> index ee564b6..0787f12 100644
> --- a/arch/powerpc/kvm/book3s_hv_ras.c
> +++ b/arch/powerpc/kvm/book3s_hv_ras.c
> @@ -177,6 +177,7 @@ void kvmppc_subcore_enter_guest(void)
>
> local_paca->sibling_subcore_state->in_guest[subcore_id] = 1;
> }
> +EXPORT_SYMBOL_GPL(kvmppc_subcore_enter_guest);
>
> void kvmppc_subcore_exit_guest(void)
> {
> @@ -187,6 +188,7 @@ void kvmppc_subcore_exit_guest(void)
>
> local_paca->sibling_subcore_state->in_guest[subcore_id] = 0;
> }
> +EXPORT_SYMBOL_GPL(kvmppc_subcore_exit_guest);
>
> static bool kvmppc_tb_resync_required(void)
> {
> diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
> b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
> index 45dd637..ea84696 100644
> --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
> +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
> @@ -47,8 +47,9 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
> #define NAPPING_NOVCPU 2
>
> /* Stack frame offsets for kvmppc_hv_entry */
> -#define SFS 160
> +#define SFS 208
> #define STACK_SLOT_TRAP (SFS-4)
> +#define STACK_SLOT_SHORT_PATH (SFS-8)
> #define STACK_SLOT_TID (SFS-16)
> #define STACK_SLOT_PSSCR (SFS-24)
> #define STACK_SLOT_PID (SFS-32)
> @@ -57,6 +58,8 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
> #define STACK_SLOT_DAWR (SFS-56)
> #define STACK_SLOT_DAWRX (SFS-64)
> #define STACK_SLOT_HFSCR (SFS-72)
> +/* the following is used by the P9 short path */
> +#define STACK_SLOT_NVGPRS (SFS-152) /* 18 gprs */
>
> /*
> * Call kvmppc_hv_entry in real mode.
> @@ -1020,6 +1023,9 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_300)
> no_xive:
> #endif /* CONFIG_KVM_XICS */
>
> + li r0, 0
> + stw r0, STACK_SLOT_SHORT_PATH(r1)
> +
> deliver_guest_interrupt: /* r4 = vcpu, r13 = paca */
> /* Check if we can deliver an external or decrementer interrupt now */
> ld r0, VCPU_PENDING_EXC(r4)
> @@ -1034,13 +1040,14 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
> bl kvmppc_guest_entry_inject_int
> ld r4, HSTATE_KVM_VCPU(r13)
> 71:
> - ld r10, VCPU_PC(r4)
> - ld r11, VCPU_MSR(r4)
> ld r6, VCPU_SRR0(r4)
> ld r7, VCPU_SRR1(r4)
> mtspr SPRN_SRR0, r6
> mtspr SPRN_SRR1, r7
>
> +fast_guest_entry_c:
> + ld r10, VCPU_PC(r4)
> + ld r11, VCPU_MSR(r4)
> /* r11 = vcpu->arch.msr & ~MSR_HV */
> rldicl r11, r11, 63 - MSR_HV_LG, 1
> rotldi r11, r11, 1 + MSR_HV_LG
> @@ -1117,6 +1124,83 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
> HRFI_TO_GUEST
> b .
>
> +/*
> + * Enter the guest on a P9 or later system where we have exactly
> + * one vcpu per vcore and we don't need to go to real mode
> + * (which implies that host and guest are both using radix MMU mode).
> + * r3 = vcpu pointer
> + * Most SPRs and all the VSRs have been loaded already.
> + */
> +_GLOBAL(__kvmhv_vcpu_entry_p9)
> +EXPORT_SYMBOL_GPL(__kvmhv_vcpu_entry_p9)
> + mflr r0
> + std r0, PPC_LR_STKOFF(r1)
> + stdu r1, -SFS(r1)
> +
> + li r0, 1
> + stw r0, STACK_SLOT_SHORT_PATH(r1)
> +
> + std r3, HSTATE_KVM_VCPU(r13)
> + mfcr r4
> + stw r4, SFS+8(r1)
> +
> + std r1, HSTATE_HOST_R1(r13)
> +
> + reg = 14
> + .rept 18
> + std reg, STACK_SLOT_NVGPRS + ((reg - 14) * 8)(r1)
> + reg = reg + 1
> + .endr
> +
> + reg = 14
> + .rept 18
> + ld reg, __VCPU_GPR(reg)(r3)
> + reg = reg + 1
> + .endr
> +
> + mfmsr r10
> + std r10, HSTATE_HOST_MSR(r13)
> +
> + mr r4, r3
> + b fast_guest_entry_c
> +guest_exit_short_path:
> +
> + li r0, KVM_GUEST_MODE_NONE
> + stb r0, HSTATE_IN_GUEST(r13)
> +
> + reg = 14
> + .rept 18
> + std reg, __VCPU_GPR(reg)(r9)
> + reg = reg + 1
> + .endr
> +
> + reg = 14
> + .rept 18
> + ld reg, STACK_SLOT_NVGPRS + ((reg - 14) * 8)(r1)
> + reg = reg + 1
> + .endr
> +
> + lwz r4, SFS+8(r1)
> + mtcr r4
> +
> + mr r3, r12 /* trap number */
> +
> + addi r1, r1, SFS
> + ld r0, PPC_LR_STKOFF(r1)
> + mtlr r0
> +
> + /* If we are in real mode, do a rfid to get back to the caller */
> + mfmsr r4
> + andi. r5, r4, MSR_IR
> + bnelr
> + rldicl r5, r4, 64 - MSR_TS_S_LG, 62 /* extract TS field */
> + mtspr SPRN_SRR0, r0
> + ld r10, HSTATE_HOST_MSR(r13)
> + rldimi r10, r5, MSR_TS_S_LG, 63 - MSR_TS_T_LG
> + mtspr SPRN_SRR1, r10
> + RFI_TO_KERNEL
> + b .
> +
> secondary_too_late:
> li r12, 0
> stw r12, STACK_SLOT_TRAP(r1)
> @@ -1377,6 +1461,11 @@ guest_exit_cont: /* r9 = vcpu, r12 =
> trap, r13 = paca */
> 1:
> #endif /* CONFIG_KVM_XICS */
>
> + /* If we came in through the P9 short path, go back out to C now */
> + lwz r0, STACK_SLOT_SHORT_PATH(r1)
> + cmpwi r0, 0
> + bne guest_exit_short_path
> +
> /* For hash guest, read the guest SLB and save it away */
> ld r5, VCPU_KVM(r9)
> lbz r0, KVM_RADIX(r5)
> diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c
> index 30c2eb7..ad4a370 100644
> --- a/arch/powerpc/kvm/book3s_xive.c
> +++ b/arch/powerpc/kvm/book3s_xive.c
> @@ -62,6 +62,69 @@
> #define XIVE_Q_GAP 2
>
> /*
> + * Push a vcpu's context to the XIVE on guest entry.
> + * This assumes we are in virtual mode (MMU on)
> + */
> +void kvmppc_xive_push_vcpu(struct kvm_vcpu *vcpu)
> +{
> + void __iomem *tima = local_paca->kvm_hstate.xive_tima_virt;
> + u64 pq;
> +
> + if (!tima)
> + return;
> + eieio();
> + __raw_writeq(vcpu->arch.xive_saved_state.w01, tima + TM_QW1_OS);
> + __raw_writel(vcpu->arch.xive_cam_word, tima + TM_QW1_OS + TM_WORD2);
> + vcpu->arch.xive_pushed = 1;
> + eieio();
> +
> + /*
> + * We clear the irq_pending flag. There is a small chance of a
> + * race vs. the escalation interrupt happening on another
> + * processor setting it again, but the only consequence is to
> + * cause a spurious wakeup on the next H_CEDE, which is not an
> + * issue.
> + */
> + vcpu->arch.irq_pending = 0;
> +
> + /*
> + * In single escalation mode, if the escalation interrupt is
> + * on, we mask it.
> + */
> + if (vcpu->arch.xive_esc_on) {
> + pq = __raw_readq((void __iomem *)(vcpu->arch.xive_esc_vaddr +
> + XIVE_ESB_SET_PQ_01));
> + mb();
> +
> + /*
> + * We have a possible subtle race here: The escalation
> + * interrupt might have fired and be on its way to the
> + * host queue while we mask it, and if we unmask it
> + * early enough (re-cede right away), there is a
> + * theorical possibility that it fires again, thus
> + * landing in the target queue more than once which is
> + * a big no-no.
> + *
> + * Fortunately, solving this is rather easy. If the
> + * above load setting PQ to 01 returns a previous
> + * value where P is set, then we know the escalation
> + * interrupt is somewhere on its way to the host. In
> + * that case we simply don't clear the xive_esc_on
> + * flag below. It will be eventually cleared by the
> + * handler for the escalation interrupt.
> + *
> + * Then, when doing a cede, we check that flag again
> + * before re-enabling the escalation interrupt, and if
> + * set, we abort the cede.
> + */
> + if (!(pq & XIVE_ESB_VAL_P))
> + /* Now P is 0, we can clear the flag */
> + vcpu->arch.xive_esc_on = 0;
> + }
> +}
> +EXPORT_SYMBOL_GPL(kvmppc_xive_push_vcpu);
> +
> +/*
> * This is a simple trigger for a generic XIVE IRQ. This must
> * only be called for interrupts that support a trigger page
> */
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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