From 800c1065c3207a1b04d4ac457a57a37ce19eeb21 Mon Sep 17 00:00:00 2001 From: Thomas Huth Date: Thu, 12 Sep 2013 10:33:45 +0200 Subject: [PATCH] KVM: s390: Lock kvm->srcu at the appropriate places The kvm->srcu lock has to be held while accessing the memory of guests and during certain other actions. This patch now adds the locks to the __vcpu_run function so that all affected code is protected now (and additionally to the KVM_S390_STORE_STATUS ioctl, which can be called out-of-band and needs a separate lock). Signed-off-by: Thomas Huth Acked-by: Christian Borntraeger Signed-off-by: Paolo Bonzini --- arch/s390/kvm/diag.c | 4 +--- arch/s390/kvm/interrupt.c | 3 +++ arch/s390/kvm/kvm-s390.c | 12 ++++++++++++ 3 files changed, 16 insertions(+), 3 deletions(-) diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c index 3a74d8af0d69..78d967f180f4 100644 --- a/arch/s390/kvm/diag.c +++ b/arch/s390/kvm/diag.c @@ -107,14 +107,13 @@ static int __diag_ipl_functions(struct kvm_vcpu *vcpu) static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu) { - int ret, idx; + int ret; /* No virtio-ccw notification? Get out quickly. */ if (!vcpu->kvm->arch.css_support || (vcpu->run->s.regs.gprs[1] != KVM_S390_VIRTIO_CCW_NOTIFY)) return -EOPNOTSUPP; - idx = srcu_read_lock(&vcpu->kvm->srcu); /* * The layout is as follows: * - gpr 2 contains the subchannel id (passed as addr) @@ -125,7 +124,6 @@ static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu) vcpu->run->s.regs.gprs[2], 8, &vcpu->run->s.regs.gprs[3], vcpu->run->s.regs.gprs[4]); - srcu_read_unlock(&vcpu->kvm->srcu, idx); /* * Return cookie in gpr 2, but don't overwrite the register if the diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 7f35cb33e510..e7323cd9f109 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -436,6 +436,7 @@ int kvm_s390_handle_wait(struct kvm_vcpu *vcpu) hrtimer_start(&vcpu->arch.ckc_timer, ktime_set (0, sltime) , HRTIMER_MODE_REL); VCPU_EVENT(vcpu, 5, "enabled wait via clock comparator: %llx ns", sltime); no_timer: + srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); spin_lock(&vcpu->arch.local_int.float_int->lock); spin_lock_bh(&vcpu->arch.local_int.lock); add_wait_queue(&vcpu->wq, &wait); @@ -455,6 +456,8 @@ no_timer: remove_wait_queue(&vcpu->wq, &wait); spin_unlock_bh(&vcpu->arch.local_int.lock); spin_unlock(&vcpu->arch.local_int.float_int->lock); + vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); + hrtimer_try_to_cancel(&vcpu->arch.ckc_timer); return 0; } diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 8eec7abc5664..1e4e7b97337a 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -752,11 +752,18 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) { int rc, exit_reason; + /* + * We try to hold kvm->srcu during most of vcpu_run (except when run- + * ning the guest), so that memslots (and other stuff) are protected + */ + vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); + do { rc = vcpu_pre_run(vcpu); if (rc) break; + srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); /* * As PF_VCPU will be used in fault handler, between * guest_enter and guest_exit should be no uaccess. @@ -767,10 +774,12 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) exit_reason = sie64a(vcpu->arch.sie_block, vcpu->run->s.regs.gprs); kvm_guest_exit(); + vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); rc = vcpu_post_run(vcpu, exit_reason); } while (!signal_pending(current) && !rc); + srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); return rc; } @@ -968,6 +977,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp, { struct kvm_vcpu *vcpu = filp->private_data; void __user *argp = (void __user *)arg; + int idx; long r; switch (ioctl) { @@ -981,7 +991,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp, break; } case KVM_S390_STORE_STATUS: + idx = srcu_read_lock(&vcpu->kvm->srcu); r = kvm_s390_vcpu_store_status(vcpu, arg); + srcu_read_unlock(&vcpu->kvm->srcu, idx); break; case KVM_S390_SET_INITIAL_PSW: { psw_t psw; -- 2.20.1