diff options
| author | Michael S. Tsirkin <mst@redhat.com> | 2012-09-16 11:50:30 +0300 |
|---|---|---|
| committer | Marcelo Tosatti <mtosatti@redhat.com> | 2012-09-17 13:46:32 -0300 |
| commit | 9fc77441e5e1bf80b794cc546d2243ee9f4afb75 (patch) | |
| tree | 4661976f4fea7606a54b3f5276c0ecb45760979c | |
| parent | 7454766f7bead388251aedee35a478356a7f4e72 (diff) | |
| download | linux-9fc77441e5e1bf80b794cc546d2243ee9f4afb75.tar.bz2 | |
KVM: make processes waiting on vcpu mutex killable
vcpu mutex can be held for unlimited time so
taking it with mutex_lock on an ioctl is wrong:
one process could be passed a vcpu fd and
call this ioctl on the vcpu used by another process,
it will then be unkillable until the owner exits.
Call mutex_lock_killable instead and return status.
Note: mutex_lock_interruptible would be even nicer,
but I am not sure all users are prepared to handle EINTR
from these ioctls. They might misinterpret it as an error.
Cleanup paths expect a vcpu that can't be used by
any userspace so this will always succeed - catch bugs
by calling BUG_ON.
Catch callers that don't check return state by adding
__must_check.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
| -rw-r--r-- | arch/x86/kvm/x86.c | 12 | ||||
| -rw-r--r-- | include/linux/kvm_host.h | 2 | ||||
| -rw-r--r-- | virt/kvm/kvm_main.c | 10 |
3 files changed, 17 insertions, 7 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c4d451ed1573..19047eafa38d 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6016,7 +6016,9 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu) int r; vcpu->arch.mtrr_state.have_fixed = 1; - vcpu_load(vcpu); + r = vcpu_load(vcpu); + if (r) + return r; r = kvm_arch_vcpu_reset(vcpu); if (r == 0) r = kvm_mmu_setup(vcpu); @@ -6027,9 +6029,11 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu) void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu) { + int r; vcpu->arch.apf.msr_val = 0; - vcpu_load(vcpu); + r = vcpu_load(vcpu); + BUG_ON(r); kvm_mmu_unload(vcpu); vcpu_put(vcpu); @@ -6275,7 +6279,9 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) static void kvm_unload_vcpu_mmu(struct kvm_vcpu *vcpu) { - vcpu_load(vcpu); + int r; + r = vcpu_load(vcpu); + BUG_ON(r); kvm_mmu_unload(vcpu); vcpu_put(vcpu); } diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 40791930bc15..80bfc880921e 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -408,7 +408,7 @@ static inline struct kvm_vcpu *kvm_get_vcpu(struct kvm *kvm, int i) int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id); void kvm_vcpu_uninit(struct kvm_vcpu *vcpu); -void vcpu_load(struct kvm_vcpu *vcpu); +int __must_check vcpu_load(struct kvm_vcpu *vcpu); void vcpu_put(struct kvm_vcpu *vcpu); int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 4fe02d900810..cc3f6dc506e4 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -131,11 +131,12 @@ bool kvm_is_mmio_pfn(pfn_t pfn) /* * Switches to specified vcpu, until a matching vcpu_put() */ -void vcpu_load(struct kvm_vcpu *vcpu) +int vcpu_load(struct kvm_vcpu *vcpu) { int cpu; - mutex_lock(&vcpu->mutex); + if (mutex_lock_killable(&vcpu->mutex)) + return -EINTR; if (unlikely(vcpu->pid != current->pids[PIDTYPE_PID].pid)) { /* The thread running this VCPU changed. */ struct pid *oldpid = vcpu->pid; @@ -148,6 +149,7 @@ void vcpu_load(struct kvm_vcpu *vcpu) preempt_notifier_register(&vcpu->preempt_notifier); kvm_arch_vcpu_load(vcpu, cpu); put_cpu(); + return 0; } void vcpu_put(struct kvm_vcpu *vcpu) @@ -1891,7 +1893,9 @@ static long kvm_vcpu_ioctl(struct file *filp, #endif - vcpu_load(vcpu); + r = vcpu_load(vcpu); + if (r) + return r; switch (ioctl) { case KVM_RUN: r = -EINVAL; |