Home Home > GIT Browse
summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorMarcelo Tosatti <mtosatti@redhat.com>2016-03-11 16:53:11 +0800
committerSasha Levin <sasha.levin@oracle.com>2016-03-14 12:42:32 -0400
commitb5c41530ef442dba667c4d964c722e8157f7da72 (patch)
treeabc695066486a4055354397e6991652504337b07
parent325940deb74b23351f507d5f1e1e01592c1efa1c (diff)
KVM: x86: move steal time initialization to vcpu entry time
[ Upstream commit 7cae2bedcbd4680b155999655e49c27b9cf020fa ] 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: Sasha Levin <sasha.levin@oracle.com>
-rw-r--r--arch/x86/kvm/x86.c9
1 files changed, 2 insertions, 7 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 42f1575ab58d..41a3fb4ed346 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2117,6 +2117,8 @@ 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;
@@ -2262,12 +2264,6 @@ 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;
@@ -2966,7 +2962,6 @@ 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);
}