From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: pgonda@google.com
Subject: [PATCH 12/12] KVM: SEV: accept signals in sev_lock_two_vms
Date: Mon, 22 Nov 2021 19:50:36 -0500 [thread overview]
Message-ID: <20211123005036.2954379-13-pbonzini@redhat.com> (raw)
In-Reply-To: <20211123005036.2954379-1-pbonzini@redhat.com>
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.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/svm/sev.c | 22 ++++++++++++++++------
1 file changed, 16 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index bbbf980c7e40..59727a966f90 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -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)
--
2.27.0
prev parent reply other threads:[~2021-11-23 0:51 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-23 0:50 [PATCH 00/12] Fixes for KVM_CAP_VM_MOVE/COPY_ENC_CONTEXT_FROM Paolo Bonzini
2021-11-23 0:50 ` [PATCH 01/12] selftests: fix check for circular KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM Paolo Bonzini
2021-12-01 15:52 ` Peter Gonda
2021-11-23 0:50 ` [PATCH 02/12] selftests: sev_migrate_tests: free all VMs Paolo Bonzini
2021-12-01 15:54 ` Peter Gonda
2021-11-23 0:50 ` [PATCH 03/12] KVM: SEV: expose KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM capability Paolo Bonzini
2021-11-29 22:28 ` Sean Christopherson
2021-12-01 15:55 ` Peter Gonda
2021-11-23 0:50 ` [PATCH 04/12] KVM: SEV: do not use list_replace_init on an empty list Paolo Bonzini
2021-11-29 22:27 ` Sean Christopherson
2021-11-23 0:50 ` [PATCH 05/12] KVM: SEV: cleanup locking for KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM Paolo Bonzini
2021-12-01 16:11 ` Peter Gonda
2021-11-23 0:50 ` [PATCH 06/12] KVM: SEV: initialize regions_list of a mirror VM Paolo Bonzini
2021-11-29 23:00 ` Sean Christopherson
2021-11-23 0:50 ` [PATCH 07/12] KVM: SEV: move mirror status to destination of KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM Paolo Bonzini
2021-11-29 23:02 ` Sean Christopherson
2021-11-23 0:50 ` [PATCH 08/12] selftests: sev_migrate_tests: add tests for KVM_CAP_VM_COPY_ENC_CONTEXT_FROM Paolo Bonzini
2021-12-01 18:09 ` Peter Gonda
2021-12-07 20:11 ` Peter Gonda
2021-11-23 0:50 ` [PATCH 09/12] KVM: SEV: Do COPY_ENC_CONTEXT_FROM with both VMs locked Paolo Bonzini
2021-11-29 23:08 ` Sean Christopherson
2021-11-23 0:50 ` [PATCH 10/12] KVM: SEV: Prohibit migration of a VM that has mirrors Paolo Bonzini
2021-11-29 22:54 ` Sean Christopherson
2021-12-01 18:17 ` Peter Gonda
2021-12-01 18:21 ` Paolo Bonzini
2021-11-23 0:50 ` [PATCH 11/12] KVM: SEV: do not take kvm->lock when destroying Paolo Bonzini
2021-11-29 22:31 ` Sean Christopherson
2021-11-23 0:50 ` Paolo Bonzini [this message]
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