diff options
| author | Marcelo Tosatti <mtosatti@redhat.com> | 2015-10-14 19:33:09 -0300 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2016-03-14 23:10:31 +0100 |
| commit | b7dc78251de7c991a3858ab5a7a56ba604cbb908 (patch) | |
| tree | ed8e3d69f96ea72e48b7ef6aaef0ecf3e2fbef02 /arch | |
| parent | 63ec4087e92fb510ab047f1115ccd9bdff37e1ef (diff) | |
KVM: x86: move steal time initialization to vcpu entry time
commit 7cae2bedcbd4680b155999655e49c27b9cf020fa upstream.
As reported at https://bugs.launchpad.net/qemu/+bug/1494350,
it is possible to have vcpu->arch.st.last_steal initialized
from a thread other than vcpu thread, say the iothread, via
KVM_SET_MSRS.
Which can cause an overflow later (when subtracting from vcpu threads
sched_info.run_delay).
To avoid that, move steal time accumulation to vcpu entry time,
before copying steal time data to guest.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/x86.c | 9 |
1 files changed, 2 insertions, 7 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index d3691ab6d6a0..356e78f2ad1a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1978,6 +1978,8 @@ static void accumulate_steal_time(struct kvm_vcpu *vcpu) static void record_steal_time(struct kvm_vcpu *vcpu) { + accumulate_steal_time(vcpu); + if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED)) return; @@ -2111,12 +2113,6 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) if (!(data & KVM_MSR_ENABLED)) break; - vcpu->arch.st.last_steal = current->sched_info.run_delay; - - preempt_disable(); - accumulate_steal_time(vcpu); - preempt_enable(); - kvm_make_request(KVM_REQ_STEAL_UPDATE, vcpu); break; @@ -2795,7 +2791,6 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) vcpu->cpu = cpu; } - accumulate_steal_time(vcpu); kvm_make_request(KVM_REQ_STEAL_UPDATE, vcpu); } |