![Linus Torvalds](/assets/img/avatar_default.png)
200 commits and noteworthy changes for most architectures. * ARM: - GICv3 save/restore - cache flushing fixes - working MSI injection for GICv3 ITS - physical timer emulation * MIPS: - various improvements under the hood - support for SMP guests - a large rewrite of MMU emulation. KVM MIPS can now use MMU notifiers to support copy-on-write, KSM, idle page tracking, swapping, ballooning and everything else. KVM_CAP_READONLY_MEM is also supported, so that writes to some memory regions can be treated as MMIO. The new MMU also paves the way for hardware virtualization support. * PPC: - support for POWER9 using the radix-tree MMU for host and guest - resizable hashed page table - bugfixes. * s390: expose more features to the guest - more SIMD extensions - instruction execution protection - ESOP2 * x86: - improved hashing in the MMU - faster PageLRU tracking for Intel CPUs without EPT A/D bits - some refactoring of nested VMX entry/exit code, preparing for live migration support of nested hypervisors - expose yet another AVX512 CPUID bit - host-to-guest PTP support - refactoring of interrupt injection, with some optimizations thrown in and some duct tape removed. - remove lazy FPU handling - optimizations of user-mode exits - optimizations of vcpu_is_preempted() for KVM guests * generic: - alternative signaling mechanism that doesn't pound on tsk->sighand->siglock -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQEcBAABAgAGBQJYral1AAoJEL/70l94x66DbNgH/Rx8YXuidFq2fe3RWOvld3RK 85OM/D5g38cTLpBE0/sJpcvX34iYN8U/l5foCZwpxB+83GHEk2Cr57JyfTogdaAJ x8dBhHKQCA/HxSQUQLN6nFqRV+yT8WUR92Fhqx82+80BSen5Yzcfee/TDoW6T1IW g8CYgX9FrRaGOX066ImAuUfdAdUVjyssfs9VttDTX+HiusPeuBPx/wsRe1ZEEPlH vnltIJQb1ETV2GOZLUojKjzH6aZkjIl29XxjkYii9JTUornClG0DfW+5QT3uLrB5 gJ+G+Zmpsq8ZBx9jNDtAi7sFsoPY1Mzf+JPNCGXBra2sP2GrBAuXcxmgznRYltQ= =8IIp -----END PGP SIGNATURE----- Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm Pull KVM updates from Paolo Bonzini: "4.11 is going to be a relatively large release for KVM, with a little over 200 commits and noteworthy changes for most architectures. ARM: - GICv3 save/restore - cache flushing fixes - working MSI injection for GICv3 ITS - physical timer emulation MIPS: - various improvements under the hood - support for SMP guests - a large rewrite of MMU emulation. KVM MIPS can now use MMU notifiers to support copy-on-write, KSM, idle page tracking, swapping, ballooning and everything else. KVM_CAP_READONLY_MEM is also supported, so that writes to some memory regions can be treated as MMIO. The new MMU also paves the way for hardware virtualization support. PPC: - support for POWER9 using the radix-tree MMU for host and guest - resizable hashed page table - bugfixes. s390: - expose more features to the guest - more SIMD extensions - instruction execution protection - ESOP2 x86: - improved hashing in the MMU - faster PageLRU tracking for Intel CPUs without EPT A/D bits - some refactoring of nested VMX entry/exit code, preparing for live migration support of nested hypervisors - expose yet another AVX512 CPUID bit - host-to-guest PTP support - refactoring of interrupt injection, with some optimizations thrown in and some duct tape removed. - remove lazy FPU handling - optimizations of user-mode exits - optimizations of vcpu_is_preempted() for KVM guests generic: - alternative signaling mechanism that doesn't pound on tsk->sighand->siglock" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (195 commits) x86/kvm: Provide optimized version of vcpu_is_preempted() for x86-64 x86/paravirt: Change vcp_is_preempted() arg type to long KVM: VMX: use correct vmcs_read/write for guest segment selector/base x86/kvm/vmx: Defer TR reload after VM exit x86/asm/64: Drop __cacheline_aligned from struct x86_hw_tss x86/kvm/vmx: Simplify segment_base() x86/kvm/vmx: Get rid of segment_base() on 64-bit kernels x86/kvm/vmx: Don't fetch the TSS base from the GDT x86/asm: Define the kernel TSS limit in a macro kvm: fix page struct leak in handle_vmon KVM: PPC: Book3S HV: Disable HPT resizing on POWER9 for now KVM: Return an error code only as a constant in kvm_get_dirty_log() KVM: Return an error code only as a constant in kvm_get_dirty_log_protect() KVM: Return directly after a failed copy_from_user() in kvm_vm_compat_ioctl() KVM: x86: remove code for lazy FPU handling KVM: race-free exit from KVM_RUN without POSIX signals KVM: PPC: Book3S HV: Turn "KVM guest htab" message into a debug message KVM: PPC: Book3S PR: Ratelimit copy data failure error messages KVM: Support vCPU-based gfn->hva cache KVM: use separate generations for each address space ...
648 lines
15 KiB
C
648 lines
15 KiB
C
/*
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* KVM paravirt_ops implementation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* Copyright (C) 2007, Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
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* Copyright IBM Corporation, 2007
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* Authors: Anthony Liguori <aliguori@us.ibm.com>
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*/
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#include <linux/context_tracking.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/kvm_para.h>
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#include <linux/cpu.h>
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#include <linux/mm.h>
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#include <linux/highmem.h>
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#include <linux/hardirq.h>
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#include <linux/notifier.h>
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#include <linux/reboot.h>
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#include <linux/hash.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/kprobes.h>
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#include <linux/debugfs.h>
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#include <linux/nmi.h>
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#include <linux/swait.h>
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#include <asm/timer.h>
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#include <asm/cpu.h>
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#include <asm/traps.h>
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#include <asm/desc.h>
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#include <asm/tlbflush.h>
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#include <asm/apic.h>
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#include <asm/apicdef.h>
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#include <asm/hypervisor.h>
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#include <asm/kvm_guest.h>
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static int kvmapf = 1;
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static int parse_no_kvmapf(char *arg)
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{
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kvmapf = 0;
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return 0;
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}
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early_param("no-kvmapf", parse_no_kvmapf);
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static int steal_acc = 1;
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static int parse_no_stealacc(char *arg)
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{
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steal_acc = 0;
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return 0;
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}
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early_param("no-steal-acc", parse_no_stealacc);
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static int kvmclock_vsyscall = 1;
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static int parse_no_kvmclock_vsyscall(char *arg)
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{
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kvmclock_vsyscall = 0;
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return 0;
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}
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early_param("no-kvmclock-vsyscall", parse_no_kvmclock_vsyscall);
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static DEFINE_PER_CPU(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64);
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static DEFINE_PER_CPU(struct kvm_steal_time, steal_time) __aligned(64);
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static int has_steal_clock = 0;
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/*
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* No need for any "IO delay" on KVM
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*/
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static void kvm_io_delay(void)
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{
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}
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#define KVM_TASK_SLEEP_HASHBITS 8
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#define KVM_TASK_SLEEP_HASHSIZE (1<<KVM_TASK_SLEEP_HASHBITS)
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struct kvm_task_sleep_node {
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struct hlist_node link;
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struct swait_queue_head wq;
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u32 token;
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int cpu;
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bool halted;
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};
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static struct kvm_task_sleep_head {
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raw_spinlock_t lock;
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struct hlist_head list;
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} async_pf_sleepers[KVM_TASK_SLEEP_HASHSIZE];
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static struct kvm_task_sleep_node *_find_apf_task(struct kvm_task_sleep_head *b,
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u32 token)
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{
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struct hlist_node *p;
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hlist_for_each(p, &b->list) {
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struct kvm_task_sleep_node *n =
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hlist_entry(p, typeof(*n), link);
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if (n->token == token)
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return n;
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}
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return NULL;
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}
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void kvm_async_pf_task_wait(u32 token)
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{
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u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
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struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
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struct kvm_task_sleep_node n, *e;
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DECLARE_SWAITQUEUE(wait);
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rcu_irq_enter();
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raw_spin_lock(&b->lock);
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e = _find_apf_task(b, token);
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if (e) {
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/* dummy entry exist -> wake up was delivered ahead of PF */
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hlist_del(&e->link);
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kfree(e);
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raw_spin_unlock(&b->lock);
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rcu_irq_exit();
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return;
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}
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n.token = token;
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n.cpu = smp_processor_id();
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n.halted = is_idle_task(current) || preempt_count() > 1;
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init_swait_queue_head(&n.wq);
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hlist_add_head(&n.link, &b->list);
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raw_spin_unlock(&b->lock);
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for (;;) {
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if (!n.halted)
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prepare_to_swait(&n.wq, &wait, TASK_UNINTERRUPTIBLE);
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if (hlist_unhashed(&n.link))
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break;
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if (!n.halted) {
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local_irq_enable();
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schedule();
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local_irq_disable();
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} else {
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/*
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* We cannot reschedule. So halt.
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*/
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rcu_irq_exit();
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native_safe_halt();
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rcu_irq_enter();
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local_irq_disable();
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}
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}
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if (!n.halted)
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finish_swait(&n.wq, &wait);
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rcu_irq_exit();
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return;
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}
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EXPORT_SYMBOL_GPL(kvm_async_pf_task_wait);
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static void apf_task_wake_one(struct kvm_task_sleep_node *n)
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{
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hlist_del_init(&n->link);
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if (n->halted)
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smp_send_reschedule(n->cpu);
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else if (swait_active(&n->wq))
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swake_up(&n->wq);
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}
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static void apf_task_wake_all(void)
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{
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int i;
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for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++) {
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struct hlist_node *p, *next;
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struct kvm_task_sleep_head *b = &async_pf_sleepers[i];
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raw_spin_lock(&b->lock);
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hlist_for_each_safe(p, next, &b->list) {
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struct kvm_task_sleep_node *n =
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hlist_entry(p, typeof(*n), link);
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if (n->cpu == smp_processor_id())
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apf_task_wake_one(n);
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}
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raw_spin_unlock(&b->lock);
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}
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}
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void kvm_async_pf_task_wake(u32 token)
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{
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u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
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struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
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struct kvm_task_sleep_node *n;
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if (token == ~0) {
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apf_task_wake_all();
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return;
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}
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again:
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raw_spin_lock(&b->lock);
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n = _find_apf_task(b, token);
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if (!n) {
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/*
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* async PF was not yet handled.
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* Add dummy entry for the token.
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*/
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n = kzalloc(sizeof(*n), GFP_ATOMIC);
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if (!n) {
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/*
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* Allocation failed! Busy wait while other cpu
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* handles async PF.
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*/
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raw_spin_unlock(&b->lock);
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cpu_relax();
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goto again;
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}
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n->token = token;
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n->cpu = smp_processor_id();
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init_swait_queue_head(&n->wq);
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hlist_add_head(&n->link, &b->list);
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} else
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apf_task_wake_one(n);
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raw_spin_unlock(&b->lock);
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return;
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}
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EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake);
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u32 kvm_read_and_reset_pf_reason(void)
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{
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u32 reason = 0;
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if (__this_cpu_read(apf_reason.enabled)) {
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reason = __this_cpu_read(apf_reason.reason);
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__this_cpu_write(apf_reason.reason, 0);
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}
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return reason;
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}
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EXPORT_SYMBOL_GPL(kvm_read_and_reset_pf_reason);
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NOKPROBE_SYMBOL(kvm_read_and_reset_pf_reason);
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dotraplinkage void
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do_async_page_fault(struct pt_regs *regs, unsigned long error_code)
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{
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enum ctx_state prev_state;
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switch (kvm_read_and_reset_pf_reason()) {
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default:
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trace_do_page_fault(regs, error_code);
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break;
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case KVM_PV_REASON_PAGE_NOT_PRESENT:
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/* page is swapped out by the host. */
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prev_state = exception_enter();
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kvm_async_pf_task_wait((u32)read_cr2());
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exception_exit(prev_state);
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break;
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case KVM_PV_REASON_PAGE_READY:
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rcu_irq_enter();
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kvm_async_pf_task_wake((u32)read_cr2());
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rcu_irq_exit();
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break;
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}
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}
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NOKPROBE_SYMBOL(do_async_page_fault);
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static void __init paravirt_ops_setup(void)
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{
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pv_info.name = "KVM";
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if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
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pv_cpu_ops.io_delay = kvm_io_delay;
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#ifdef CONFIG_X86_IO_APIC
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no_timer_check = 1;
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#endif
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}
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static void kvm_register_steal_time(void)
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{
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int cpu = smp_processor_id();
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struct kvm_steal_time *st = &per_cpu(steal_time, cpu);
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if (!has_steal_clock)
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return;
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wrmsrl(MSR_KVM_STEAL_TIME, (slow_virt_to_phys(st) | KVM_MSR_ENABLED));
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pr_info("kvm-stealtime: cpu %d, msr %llx\n",
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cpu, (unsigned long long) slow_virt_to_phys(st));
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}
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static DEFINE_PER_CPU(unsigned long, kvm_apic_eoi) = KVM_PV_EOI_DISABLED;
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static notrace void kvm_guest_apic_eoi_write(u32 reg, u32 val)
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{
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/**
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* This relies on __test_and_clear_bit to modify the memory
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* in a way that is atomic with respect to the local CPU.
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* The hypervisor only accesses this memory from the local CPU so
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* there's no need for lock or memory barriers.
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* An optimization barrier is implied in apic write.
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*/
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if (__test_and_clear_bit(KVM_PV_EOI_BIT, this_cpu_ptr(&kvm_apic_eoi)))
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return;
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apic->native_eoi_write(APIC_EOI, APIC_EOI_ACK);
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}
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static void kvm_guest_cpu_init(void)
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{
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if (!kvm_para_available())
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return;
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if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF) && kvmapf) {
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u64 pa = slow_virt_to_phys(this_cpu_ptr(&apf_reason));
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#ifdef CONFIG_PREEMPT
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pa |= KVM_ASYNC_PF_SEND_ALWAYS;
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#endif
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wrmsrl(MSR_KVM_ASYNC_PF_EN, pa | KVM_ASYNC_PF_ENABLED);
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__this_cpu_write(apf_reason.enabled, 1);
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printk(KERN_INFO"KVM setup async PF for cpu %d\n",
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smp_processor_id());
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}
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if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) {
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unsigned long pa;
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/* Size alignment is implied but just to make it explicit. */
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BUILD_BUG_ON(__alignof__(kvm_apic_eoi) < 4);
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__this_cpu_write(kvm_apic_eoi, 0);
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pa = slow_virt_to_phys(this_cpu_ptr(&kvm_apic_eoi))
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| KVM_MSR_ENABLED;
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wrmsrl(MSR_KVM_PV_EOI_EN, pa);
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}
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if (has_steal_clock)
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kvm_register_steal_time();
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}
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static void kvm_pv_disable_apf(void)
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{
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if (!__this_cpu_read(apf_reason.enabled))
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return;
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wrmsrl(MSR_KVM_ASYNC_PF_EN, 0);
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__this_cpu_write(apf_reason.enabled, 0);
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printk(KERN_INFO"Unregister pv shared memory for cpu %d\n",
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smp_processor_id());
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}
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static void kvm_pv_guest_cpu_reboot(void *unused)
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{
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/*
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* We disable PV EOI before we load a new kernel by kexec,
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* since MSR_KVM_PV_EOI_EN stores a pointer into old kernel's memory.
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* New kernel can re-enable when it boots.
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*/
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if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
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wrmsrl(MSR_KVM_PV_EOI_EN, 0);
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kvm_pv_disable_apf();
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kvm_disable_steal_time();
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}
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static int kvm_pv_reboot_notify(struct notifier_block *nb,
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unsigned long code, void *unused)
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{
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if (code == SYS_RESTART)
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on_each_cpu(kvm_pv_guest_cpu_reboot, NULL, 1);
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return NOTIFY_DONE;
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}
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static struct notifier_block kvm_pv_reboot_nb = {
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.notifier_call = kvm_pv_reboot_notify,
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};
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static u64 kvm_steal_clock(int cpu)
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{
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u64 steal;
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struct kvm_steal_time *src;
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int version;
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src = &per_cpu(steal_time, cpu);
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do {
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version = src->version;
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rmb();
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steal = src->steal;
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rmb();
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} while ((version & 1) || (version != src->version));
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return steal;
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}
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void kvm_disable_steal_time(void)
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{
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if (!has_steal_clock)
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return;
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wrmsr(MSR_KVM_STEAL_TIME, 0, 0);
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}
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#ifdef CONFIG_SMP
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static void __init kvm_smp_prepare_boot_cpu(void)
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{
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kvm_guest_cpu_init();
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native_smp_prepare_boot_cpu();
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kvm_spinlock_init();
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}
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static void kvm_guest_cpu_offline(void)
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{
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kvm_disable_steal_time();
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if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
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wrmsrl(MSR_KVM_PV_EOI_EN, 0);
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kvm_pv_disable_apf();
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apf_task_wake_all();
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}
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static int kvm_cpu_online(unsigned int cpu)
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{
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local_irq_disable();
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kvm_guest_cpu_init();
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local_irq_enable();
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return 0;
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}
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static int kvm_cpu_down_prepare(unsigned int cpu)
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{
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local_irq_disable();
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kvm_guest_cpu_offline();
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local_irq_enable();
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return 0;
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}
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#endif
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static void __init kvm_apf_trap_init(void)
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{
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set_intr_gate(14, async_page_fault);
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}
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void __init kvm_guest_init(void)
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{
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int i;
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if (!kvm_para_available())
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return;
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paravirt_ops_setup();
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register_reboot_notifier(&kvm_pv_reboot_nb);
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for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++)
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raw_spin_lock_init(&async_pf_sleepers[i].lock);
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if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF))
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x86_init.irqs.trap_init = kvm_apf_trap_init;
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if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
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has_steal_clock = 1;
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pv_time_ops.steal_clock = kvm_steal_clock;
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}
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if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
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apic_set_eoi_write(kvm_guest_apic_eoi_write);
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if (kvmclock_vsyscall)
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kvm_setup_vsyscall_timeinfo();
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#ifdef CONFIG_SMP
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smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
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if (cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/kvm:online",
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kvm_cpu_online, kvm_cpu_down_prepare) < 0)
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pr_err("kvm_guest: Failed to install cpu hotplug callbacks\n");
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#else
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kvm_guest_cpu_init();
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#endif
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/*
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* Hard lockup detection is enabled by default. Disable it, as guests
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* can get false positives too easily, for example if the host is
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* overcommitted.
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*/
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hardlockup_detector_disable();
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}
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static noinline uint32_t __kvm_cpuid_base(void)
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{
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if (boot_cpu_data.cpuid_level < 0)
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return 0; /* So we don't blow up on old processors */
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if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
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return hypervisor_cpuid_base("KVMKVMKVM\0\0\0", 0);
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return 0;
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}
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static inline uint32_t kvm_cpuid_base(void)
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{
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static int kvm_cpuid_base = -1;
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if (kvm_cpuid_base == -1)
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kvm_cpuid_base = __kvm_cpuid_base();
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return kvm_cpuid_base;
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}
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bool kvm_para_available(void)
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{
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return kvm_cpuid_base() != 0;
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}
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EXPORT_SYMBOL_GPL(kvm_para_available);
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unsigned int kvm_arch_para_features(void)
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{
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return cpuid_eax(kvm_cpuid_base() | KVM_CPUID_FEATURES);
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}
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static uint32_t __init kvm_detect(void)
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{
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return kvm_cpuid_base();
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}
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const struct hypervisor_x86 x86_hyper_kvm __refconst = {
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.name = "KVM",
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.detect = kvm_detect,
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.x2apic_available = kvm_para_available,
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};
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EXPORT_SYMBOL_GPL(x86_hyper_kvm);
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static __init int activate_jump_labels(void)
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{
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if (has_steal_clock) {
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static_key_slow_inc(¶virt_steal_enabled);
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if (steal_acc)
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static_key_slow_inc(¶virt_steal_rq_enabled);
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}
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return 0;
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}
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arch_initcall(activate_jump_labels);
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#ifdef CONFIG_PARAVIRT_SPINLOCKS
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/* Kick a cpu by its apicid. Used to wake up a halted vcpu */
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static void kvm_kick_cpu(int cpu)
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{
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int apicid;
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unsigned long flags = 0;
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apicid = per_cpu(x86_cpu_to_apicid, cpu);
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kvm_hypercall2(KVM_HC_KICK_CPU, flags, apicid);
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}
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#include <asm/qspinlock.h>
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static void kvm_wait(u8 *ptr, u8 val)
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{
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unsigned long flags;
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if (in_nmi())
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return;
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local_irq_save(flags);
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if (READ_ONCE(*ptr) != val)
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goto out;
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/*
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* halt until it's our turn and kicked. Note that we do safe halt
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* for irq enabled case to avoid hang when lock info is overwritten
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* in irq spinlock slowpath and no spurious interrupt occur to save us.
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*/
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if (arch_irqs_disabled_flags(flags))
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halt();
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else
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safe_halt();
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out:
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local_irq_restore(flags);
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}
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#ifdef CONFIG_X86_32
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__visible bool __kvm_vcpu_is_preempted(long cpu)
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{
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struct kvm_steal_time *src = &per_cpu(steal_time, cpu);
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return !!src->preempted;
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}
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PV_CALLEE_SAVE_REGS_THUNK(__kvm_vcpu_is_preempted);
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#else
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#include <asm/asm-offsets.h>
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extern bool __raw_callee_save___kvm_vcpu_is_preempted(long);
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/*
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* Hand-optimize version for x86-64 to avoid 8 64-bit register saving and
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* restoring to/from the stack.
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*/
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asm(
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".pushsection .text;"
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".global __raw_callee_save___kvm_vcpu_is_preempted;"
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".type __raw_callee_save___kvm_vcpu_is_preempted, @function;"
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"__raw_callee_save___kvm_vcpu_is_preempted:"
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"movq __per_cpu_offset(,%rdi,8), %rax;"
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"cmpb $0, " __stringify(KVM_STEAL_TIME_preempted) "+steal_time(%rax);"
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"setne %al;"
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"ret;"
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".popsection");
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#endif
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/*
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* Setup pv_lock_ops to exploit KVM_FEATURE_PV_UNHALT if present.
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*/
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void __init kvm_spinlock_init(void)
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{
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if (!kvm_para_available())
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return;
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/* Does host kernel support KVM_FEATURE_PV_UNHALT? */
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if (!kvm_para_has_feature(KVM_FEATURE_PV_UNHALT))
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return;
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__pv_init_lock_hash();
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pv_lock_ops.queued_spin_lock_slowpath = __pv_queued_spin_lock_slowpath;
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pv_lock_ops.queued_spin_unlock = PV_CALLEE_SAVE(__pv_queued_spin_unlock);
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pv_lock_ops.wait = kvm_wait;
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pv_lock_ops.kick = kvm_kick_cpu;
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if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
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pv_lock_ops.vcpu_is_preempted =
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PV_CALLEE_SAVE(__kvm_vcpu_is_preempted);
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}
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}
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#endif /* CONFIG_PARAVIRT_SPINLOCKS */
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