From 6109c5a6ab7f38ed8e1beb06a90aa83884c18700 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 8 Oct 2021 19:12:03 -0700 Subject: KVM: arm64: Move vGIC v4 handling for WFI out arch callback hook Move the put and reload of the vGIC out of the block/unblock callbacks and into a dedicated WFI helper. Functionally, this is nearly a nop as the block hook is called at the very beginning of kvm_vcpu_block(), and the only code in kvm_vcpu_block() after the unblock hook is to update the halt-polling controls, i.e. can only affect the next WFI. Back when the arch (un)blocking hooks were added by commits 3217f7c25bca ("KVM: Add kvm_arch_vcpu_{un}blocking callbacks) and d35268da6687 ("arm/arm64: KVM: arch_timer: Only schedule soft timer on vcpu_block"), the hooks were invoked only when KVM was about to "block", i.e. schedule out the vCPU. The use case at the time was to schedule a timer in the host based on the earliest timer in the guest in order to wake the blocking vCPU when the emulated guest timer fired. Commit accb99bcd0ca ("KVM: arm/arm64: Simplify bg_timer programming") reworked the timer logic to be even more precise, by waiting until the vCPU was actually scheduled out, and so move the timer logic from the (un)blocking hooks to vcpu_load/put. In the meantime, the hooks gained usage for enabling vGIC v4 doorbells in commit df9ba95993b9 ("KVM: arm/arm64: GICv4: Use the doorbell interrupt as an unblocking source"), and added related logic for the VMCR in commit 5eeaf10eec39 ("KVM: arm/arm64: Sync ICH_VMCR_EL2 back when about to block"). Finally, commit 07ab0f8d9a12 ("KVM: Call kvm_arch_vcpu_blocking early into the blocking sequence") hoisted the (un)blocking hooks so that they wrapped KVM's halt-polling logic in addition to the core "block" logic. In other words, the original need for arch hooks to take action _only_ in the block path is long since gone. Cc: Oliver Upton Cc: Marc Zyngier Signed-off-by: Sean Christopherson Message-Id: <20211009021236.4122790-11-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/arm64/kvm/handle_exit.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'arch/arm64/kvm/handle_exit.c') diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index 275a27368a04..4794563a506b 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -95,8 +95,7 @@ static int kvm_handle_wfx(struct kvm_vcpu *vcpu) } else { trace_kvm_wfx_arm64(*vcpu_pc(vcpu), false); vcpu->stat.wfi_exit_stat++; - kvm_vcpu_block(vcpu); - kvm_clear_request(KVM_REQ_UNHALT, vcpu); + kvm_vcpu_wfi(vcpu); } kvm_incr_pc(vcpu); -- cgit v1.2.3 From 91b99ea7065786d0bff1c9281b002455dbaeb08b Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 8 Oct 2021 19:12:06 -0700 Subject: KVM: Rename kvm_vcpu_block() => kvm_vcpu_halt() Rename kvm_vcpu_block() to kvm_vcpu_halt() in preparation for splitting the actual "block" sequences into a separate helper (to be named kvm_vcpu_block()). x86 will use the standalone block-only path to handle non-halt cases where the vCPU is not runnable. Rename block_ns to halt_ns to match the new function name. No functional change intended. Reviewed-by: David Matlack Reviewed-by: Christian Borntraeger Signed-off-by: Sean Christopherson Message-Id: <20211009021236.4122790-14-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/arm64/kvm/arch_timer.c | 2 +- arch/arm64/kvm/arm.c | 2 +- arch/arm64/kvm/handle_exit.c | 2 +- arch/arm64/kvm/psci.c | 2 +- arch/mips/kvm/emulate.c | 2 +- arch/powerpc/kvm/book3s_pr.c | 2 +- arch/powerpc/kvm/book3s_pr_papr.c | 2 +- arch/powerpc/kvm/booke.c | 2 +- arch/powerpc/kvm/powerpc.c | 2 +- arch/riscv/kvm/vcpu_exit.c | 2 +- arch/s390/kvm/interrupt.c | 2 +- arch/x86/kvm/x86.c | 11 +++++++++-- include/linux/kvm_host.h | 2 +- virt/kvm/kvm_main.c | 20 +++++++++----------- 14 files changed, 30 insertions(+), 25 deletions(-) (limited to 'arch/arm64/kvm/handle_exit.c') diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c index d6f4114f1d11..3aeaa79ad4a2 100644 --- a/arch/arm64/kvm/arch_timer.c +++ b/arch/arm64/kvm/arch_timer.c @@ -467,7 +467,7 @@ out: } /* - * Schedule the background timer before calling kvm_vcpu_block, so that this + * Schedule the background timer before calling kvm_vcpu_halt, so that this * thread is removed from its waitqueue and made runnable when there's a timer * interrupt to handle. */ diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index ced54a3a3db0..77ecc11d67ae 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -681,7 +681,7 @@ void kvm_vcpu_wfi(struct kvm_vcpu *vcpu) vgic_v4_put(vcpu, true); preempt_enable(); - kvm_vcpu_block(vcpu); + kvm_vcpu_halt(vcpu); kvm_clear_request(KVM_REQ_UNHALT, vcpu); preempt_disable(); diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index 4794563a506b..6d0baf71aa67 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -82,7 +82,7 @@ static int handle_no_fpsimd(struct kvm_vcpu *vcpu) * * WFE: Yield the CPU and come back to this vcpu when the scheduler * decides to. - * WFI: Simply call kvm_vcpu_block(), which will halt execution of + * WFI: Simply call kvm_vcpu_halt(), which will halt execution of * world-switches and schedule other host processes until there is an * incoming IRQ or FIQ to the VM. */ diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c index ed675fce8fb7..ad6c9ef32928 100644 --- a/arch/arm64/kvm/psci.c +++ b/arch/arm64/kvm/psci.c @@ -46,7 +46,7 @@ static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu) * specification (ARM DEN 0022A). This means all suspend states * for KVM will preserve the register state. */ - kvm_vcpu_block(vcpu); + kvm_vcpu_halt(vcpu); kvm_clear_request(KVM_REQ_UNHALT, vcpu); return PSCI_RET_SUCCESS; diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c index 22e745e49b0a..b494d8d39290 100644 --- a/arch/mips/kvm/emulate.c +++ b/arch/mips/kvm/emulate.c @@ -952,7 +952,7 @@ enum emulation_result kvm_mips_emul_wait(struct kvm_vcpu *vcpu) if (!vcpu->arch.pending_exceptions) { kvm_vz_lose_htimer(vcpu); vcpu->arch.wait = 1; - kvm_vcpu_block(vcpu); + kvm_vcpu_halt(vcpu); /* * We we are runnable, then definitely go off to user space to diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c index 30426e8c8cf6..34a801c3604a 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -492,7 +492,7 @@ static void kvmppc_set_msr_pr(struct kvm_vcpu *vcpu, u64 msr) if (msr & MSR_POW) { if (!vcpu->arch.pending_exceptions) { - kvm_vcpu_block(vcpu); + kvm_vcpu_halt(vcpu); kvm_clear_request(KVM_REQ_UNHALT, vcpu); vcpu->stat.generic.halt_wakeup++; diff --git a/arch/powerpc/kvm/book3s_pr_papr.c b/arch/powerpc/kvm/book3s_pr_papr.c index ac14239f3424..1f10e7dfcdd0 100644 --- a/arch/powerpc/kvm/book3s_pr_papr.c +++ b/arch/powerpc/kvm/book3s_pr_papr.c @@ -376,7 +376,7 @@ int kvmppc_h_pr(struct kvm_vcpu *vcpu, unsigned long cmd) return kvmppc_h_pr_stuff_tce(vcpu); case H_CEDE: kvmppc_set_msr_fast(vcpu, kvmppc_get_msr(vcpu) | MSR_EE); - kvm_vcpu_block(vcpu); + kvm_vcpu_halt(vcpu); kvm_clear_request(KVM_REQ_UNHALT, vcpu); vcpu->stat.generic.halt_wakeup++; return EMULATE_DONE; diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c index 53b4c9597c30..06c5830a93f9 100644 --- a/arch/powerpc/kvm/booke.c +++ b/arch/powerpc/kvm/booke.c @@ -718,7 +718,7 @@ int kvmppc_core_prepare_to_enter(struct kvm_vcpu *vcpu) if (vcpu->arch.shared->msr & MSR_WE) { local_irq_enable(); - kvm_vcpu_block(vcpu); + kvm_vcpu_halt(vcpu); kvm_clear_request(KVM_REQ_UNHALT, vcpu); hard_irq_disable(); diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 7de9ddbc6af1..2ad0ccd202d5 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -236,7 +236,7 @@ int kvmppc_kvm_pv(struct kvm_vcpu *vcpu) break; case EV_HCALL_TOKEN(EV_IDLE): r = EV_SUCCESS; - kvm_vcpu_block(vcpu); + kvm_vcpu_halt(vcpu); kvm_clear_request(KVM_REQ_UNHALT, vcpu); break; default: diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c index 7f2d742ae4c6..571f319e995a 100644 --- a/arch/riscv/kvm/vcpu_exit.c +++ b/arch/riscv/kvm/vcpu_exit.c @@ -146,7 +146,7 @@ static int system_opcode_insn(struct kvm_vcpu *vcpu, vcpu->stat.wfi_exit_stat++; if (!kvm_arch_vcpu_runnable(vcpu)) { srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx); - kvm_vcpu_block(vcpu); + kvm_vcpu_halt(vcpu); vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); kvm_clear_request(KVM_REQ_UNHALT, vcpu); } diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 3c8246fa208b..dbabd6f2404e 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -1335,7 +1335,7 @@ int kvm_s390_handle_wait(struct kvm_vcpu *vcpu) VCPU_EVENT(vcpu, 4, "enabled wait: %llu ns", sltime); no_timer: srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); - kvm_vcpu_block(vcpu); + kvm_vcpu_halt(vcpu); vcpu->valid_wakeup = false; __unset_cpu_idle(vcpu); vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 43cabc747318..e3dd76f251e9 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8727,6 +8727,13 @@ void kvm_arch_exit(void) static int __kvm_emulate_halt(struct kvm_vcpu *vcpu, int state, int reason) { + /* + * The vCPU has halted, e.g. executed HLT. Update the run state if the + * local APIC is in-kernel, the run loop will detect the non-runnable + * state and halt the vCPU. Exit to userspace if the local APIC is + * managed by userspace, in which case userspace is responsible for + * handling wake events. + */ ++vcpu->stat.halt_exits; if (lapic_in_kernel(vcpu)) { vcpu->arch.mp_state = state; @@ -9999,7 +10006,7 @@ static inline int vcpu_block(struct kvm *kvm, struct kvm_vcpu *vcpu) if (!kvm_arch_vcpu_runnable(vcpu) && (!kvm_x86_ops.pre_block || static_call(kvm_x86_pre_block)(vcpu) == 0)) { srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx); - kvm_vcpu_block(vcpu); + kvm_vcpu_halt(vcpu); vcpu->srcu_idx = srcu_read_lock(&kvm->srcu); if (kvm_x86_ops.post_block) @@ -10196,7 +10203,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) r = -EINTR; goto out; } - kvm_vcpu_block(vcpu); + kvm_vcpu_halt(vcpu); if (kvm_apic_accept_events(vcpu) < 0) { r = 0; goto out; diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index afacbfb2e482..ea3c22d55d56 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1102,7 +1102,7 @@ void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, gfn_t gfn); void kvm_sigset_activate(struct kvm_vcpu *vcpu); void kvm_sigset_deactivate(struct kvm_vcpu *vcpu); -void kvm_vcpu_block(struct kvm_vcpu *vcpu); +void kvm_vcpu_halt(struct kvm_vcpu *vcpu); void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu); void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu); bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 53c58606e1e2..0d301c95fa1a 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3294,17 +3294,14 @@ static inline void update_halt_poll_stats(struct kvm_vcpu *vcpu, ktime_t start, } } -/* - * The vCPU has executed a HLT instruction with in-kernel mode enabled. - */ -void kvm_vcpu_block(struct kvm_vcpu *vcpu) +void kvm_vcpu_halt(struct kvm_vcpu *vcpu) { struct rcuwait *wait = kvm_arch_vcpu_get_wait(vcpu); bool halt_poll_allowed = !kvm_arch_no_poll(vcpu); bool do_halt_poll = halt_poll_allowed && vcpu->halt_poll_ns; ktime_t start, cur, poll_end; bool waited = false; - u64 block_ns; + u64 halt_ns; start = cur = poll_end = ktime_get(); if (do_halt_poll) { @@ -3346,7 +3343,8 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu) ktime_to_ns(cur) - ktime_to_ns(poll_end)); } out: - block_ns = ktime_to_ns(cur) - ktime_to_ns(start); + /* The total time the vCPU was "halted", including polling time. */ + halt_ns = ktime_to_ns(cur) - ktime_to_ns(start); /* * Note, halt-polling is considered successful so long as the vCPU was @@ -3360,24 +3358,24 @@ out: if (!vcpu_valid_wakeup(vcpu)) { shrink_halt_poll_ns(vcpu); } else if (vcpu->kvm->max_halt_poll_ns) { - if (block_ns <= vcpu->halt_poll_ns) + if (halt_ns <= vcpu->halt_poll_ns) ; /* we had a long block, shrink polling */ else if (vcpu->halt_poll_ns && - block_ns > vcpu->kvm->max_halt_poll_ns) + halt_ns > vcpu->kvm->max_halt_poll_ns) shrink_halt_poll_ns(vcpu); /* we had a short halt and our poll time is too small */ else if (vcpu->halt_poll_ns < vcpu->kvm->max_halt_poll_ns && - block_ns < vcpu->kvm->max_halt_poll_ns) + halt_ns < vcpu->kvm->max_halt_poll_ns) grow_halt_poll_ns(vcpu); } else { vcpu->halt_poll_ns = 0; } } - trace_kvm_vcpu_wakeup(block_ns, waited, vcpu_valid_wakeup(vcpu)); + trace_kvm_vcpu_wakeup(halt_ns, waited, vcpu_valid_wakeup(vcpu)); } -EXPORT_SYMBOL_GPL(kvm_vcpu_block); +EXPORT_SYMBOL_GPL(kvm_vcpu_halt); bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu) { -- cgit v1.2.3