diff options
| author | Marcelo Tosatti <mtosatti@redhat.com> | 2015-10-14 19:33:09 -0300 |
|---|---|---|
| committer | Zefan Li <lizefan@huawei.com> | 2016-03-21 09:17:59 +0800 |
| commit | 6d470d7cebd87e956e255b242d6c7f4a7d5b62b5 (patch) | |
| tree | e1e34641c2148f22788d07eb51a977c05269ac85 | |
| parent | 24fa51bde52b3671afa476c96d63bcf8a4e8a307 (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: Zefan Li <lizefan@huawei.com>
| -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 4ad2b7bb382e..9cc83e287adf 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1545,6 +1545,8 @@ 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; @@ -1665,12 +1667,6 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data) 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; @@ -2327,7 +2323,6 @@ 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); } |