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KVM: SEV: accept signals in sev_lock_two_vms

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Generally, kvm->lock is not taken for a long time, but
sev_lock_two_vms is different: it takes vCPU locks
inside, so userspace can hold it back just by calling
a vCPU ioctl.  Play it safe and use mutex_lock_killable.

Message-Id: <20211123005036.2954379-13-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2021-11-22 19:50:36 -05:00
parent 10a37929ef
commit c9d61dcb0b
1 changed files with 16 additions and 6 deletions
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22
arch/x86/kvm/svm/sev.c
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@ -1547,6 +1547,7 @@ static int sev_lock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm)
{
struct kvm_sev_info *dst_sev = &to_kvm_svm(dst_kvm)->sev_info;
struct kvm_sev_info *src_sev = &to_kvm_svm(src_kvm)->sev_info;
int r = -EBUSY;
if (dst_kvm == src_kvm)
return -EINVAL;
@ -1558,14 +1559,23 @@ static int sev_lock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm)
if (atomic_cmpxchg_acquire(&dst_sev->migration_in_progress, 0, 1))
return -EBUSY;
if (atomic_cmpxchg_acquire(&src_sev->migration_in_progress, 0, 1)) {
atomic_set_release(&dst_sev->migration_in_progress, 0);
return -EBUSY;
}
if (atomic_cmpxchg_acquire(&src_sev->migration_in_progress, 0, 1))
goto release_dst;
mutex_lock(&dst_kvm->lock);
mutex_lock(&src_kvm->lock);
r = -EINTR;
if (mutex_lock_killable(&dst_kvm->lock))
goto release_src;
if (mutex_lock_killable(&src_kvm->lock))
goto unlock_dst;
return 0;
unlock_dst:
mutex_unlock(&dst_kvm->lock);
release_src:
atomic_set_release(&src_sev->migration_in_progress, 0);
release_dst:
atomic_set_release(&dst_sev->migration_in_progress, 0);
return r;
}
static void sev_unlock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm)