diff options
author | Sean Christopherson <seanjc@google.com> | 2022-04-15 00:43:43 +0000 |
---|---|---|
committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-04-21 13:16:11 -0400 |
commit | 2031f2876896d82aca7e82f84accd9181b9587fb (patch) | |
tree | 3738b7477aeb1e7436fa3a01a0a3ff63d0266952 /arch/x86 | |
parent | fdd6f6ac2e489b9b256cd05a880d13bfdbac7c2e (diff) | |
download | linux-2031f2876896d82aca7e82f84accd9181b9587fb.tar.bz2 |
KVM: Add helpers to wrap vcpu->srcu_idx and yell if it's abused
Add wrappers to acquire/release KVM's SRCU lock when stashing the index
in vcpu->src_idx, along with rudimentary detection of illegal usage,
e.g. re-acquiring SRCU and thus overwriting vcpu->src_idx. Because the
SRCU index is (currently) either 0 or 1, illegal nesting bugs can go
unnoticed for quite some time and only cause problems when the nested
lock happens to get a different index.
Wrap the WARNs in PROVE_RCU=y, and make them ONCE, otherwise KVM will
likely yell so loudly that it will bring the kernel to its knees.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Fabiano Rosas <farosas@linux.ibm.com>
Message-Id: <20220415004343.2203171-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
-rw-r--r-- | arch/x86/kvm/x86.c | 28 |
1 files changed, 13 insertions, 15 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 867c0fd8d187..51eb27824452 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10097,7 +10097,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) /* Store vcpu->apicv_active before vcpu->mode. */ smp_store_release(&vcpu->mode, IN_GUEST_MODE); - srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); + kvm_vcpu_srcu_read_unlock(vcpu); /* * 1) We should set ->mode before checking ->requests. Please see @@ -10128,7 +10128,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) smp_wmb(); local_irq_enable(); preempt_enable(); - vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); + kvm_vcpu_srcu_read_lock(vcpu); r = 1; goto cancel_injection; } @@ -10254,7 +10254,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) local_irq_enable(); preempt_enable(); - vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); + kvm_vcpu_srcu_read_lock(vcpu); /* * Profile KVM exit RIPs: @@ -10284,7 +10284,7 @@ out: } /* Called within kvm->srcu read side. */ -static inline int vcpu_block(struct kvm *kvm, struct kvm_vcpu *vcpu) +static inline int vcpu_block(struct kvm_vcpu *vcpu) { bool hv_timer; @@ -10300,12 +10300,12 @@ static inline int vcpu_block(struct kvm *kvm, struct kvm_vcpu *vcpu) if (hv_timer) kvm_lapic_switch_to_sw_timer(vcpu); - srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx); + kvm_vcpu_srcu_read_unlock(vcpu); if (vcpu->arch.mp_state == KVM_MP_STATE_HALTED) kvm_vcpu_halt(vcpu); else kvm_vcpu_block(vcpu); - vcpu->srcu_idx = srcu_read_lock(&kvm->srcu); + kvm_vcpu_srcu_read_lock(vcpu); if (hv_timer) kvm_lapic_switch_to_hv_timer(vcpu); @@ -10347,7 +10347,6 @@ static inline bool kvm_vcpu_running(struct kvm_vcpu *vcpu) static int vcpu_run(struct kvm_vcpu *vcpu) { int r; - struct kvm *kvm = vcpu->kvm; vcpu->arch.l1tf_flush_l1d = true; @@ -10355,7 +10354,7 @@ static int vcpu_run(struct kvm_vcpu *vcpu) if (kvm_vcpu_running(vcpu)) { r = vcpu_enter_guest(vcpu); } else { - r = vcpu_block(kvm, vcpu); + r = vcpu_block(vcpu); } if (r <= 0) @@ -10374,9 +10373,9 @@ static int vcpu_run(struct kvm_vcpu *vcpu) } if (__xfer_to_guest_mode_work_pending()) { - srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx); + kvm_vcpu_srcu_read_unlock(vcpu); r = xfer_to_guest_mode_handle_work(vcpu); - vcpu->srcu_idx = srcu_read_lock(&kvm->srcu); + kvm_vcpu_srcu_read_lock(vcpu); if (r) return r; } @@ -10479,7 +10478,6 @@ static void kvm_put_guest_fpu(struct kvm_vcpu *vcpu) int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) { struct kvm_run *kvm_run = vcpu->run; - struct kvm *kvm = vcpu->kvm; int r; vcpu_load(vcpu); @@ -10487,7 +10485,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) kvm_run->flags = 0; kvm_load_guest_fpu(vcpu); - vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); + kvm_vcpu_srcu_read_lock(vcpu); if (unlikely(vcpu->arch.mp_state == KVM_MP_STATE_UNINITIALIZED)) { if (kvm_run->immediate_exit) { r = -EINTR; @@ -10499,9 +10497,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) */ WARN_ON_ONCE(kvm_lapic_hv_timer_in_use(vcpu)); - srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx); + kvm_vcpu_srcu_read_unlock(vcpu); kvm_vcpu_block(vcpu); - vcpu->srcu_idx = srcu_read_lock(&kvm->srcu); + kvm_vcpu_srcu_read_lock(vcpu); if (kvm_apic_accept_events(vcpu) < 0) { r = 0; @@ -10562,7 +10560,7 @@ out: if (kvm_run->kvm_valid_regs) store_regs(vcpu); post_kvm_run_save(vcpu); - srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx); + kvm_vcpu_srcu_read_unlock(vcpu); kvm_sigset_deactivate(vcpu); vcpu_put(vcpu); |