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| author | Marcelo Tosatti | 2013-08-28 04:55:29 +0200 |
|---|---|---|
| committer | Gleb Natapov | 2013-08-28 16:36:11 +0200 |
| commit | 2e762ff79fd0793cfa71d3913e2eb664b7b11031 (patch) | |
| tree | 0c8dd496830d9cf7e16e17b0e0a2cb7454175859 /arch/x86/kvm/x86.c | |
| parent | KVM: x86: add comments where MMIO does not return to the emulator (diff) | |
| download | kernel-qcow2-linux-2e762ff79fd0793cfa71d3913e2eb664b7b11031.tar.gz kernel-qcow2-linux-2e762ff79fd0793cfa71d3913e2eb664b7b11031.tar.xz kernel-qcow2-linux-2e762ff79fd0793cfa71d3913e2eb664b7b11031.zip | |
KVM: x86: update masterclock when kvmclock_offset is calculated (v2)
The offset to add to the hosts monotonic time, kvmclock_offset, is
calculated against the monotonic time at KVM_SET_CLOCK ioctl time.
Request a master clock update at this time, to reduce a potentially
unbounded difference between the values of the masterclock and
the clock value used to calculate kvmclock_offset.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 47 |
1 files changed, 24 insertions, 23 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e514b3cb8b93..e5ca72a5cdb6 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1447,6 +1447,29 @@ static void pvclock_update_vm_gtod_copy(struct kvm *kvm) #endif } +static void kvm_gen_update_masterclock(struct kvm *kvm) +{ +#ifdef CONFIG_X86_64 + int i; + struct kvm_vcpu *vcpu; + struct kvm_arch *ka = &kvm->arch; + + spin_lock(&ka->pvclock_gtod_sync_lock); + kvm_make_mclock_inprogress_request(kvm); + /* no guest entries from this point */ + pvclock_update_vm_gtod_copy(kvm); + + kvm_for_each_vcpu(i, vcpu, kvm) + set_bit(KVM_REQ_CLOCK_UPDATE, &vcpu->requests); + + /* guest entries allowed */ + kvm_for_each_vcpu(i, vcpu, kvm) + clear_bit(KVM_REQ_MCLOCK_INPROGRESS, &vcpu->requests); + + spin_unlock(&ka->pvclock_gtod_sync_lock); +#endif +} + static int kvm_guest_time_update(struct kvm_vcpu *v) { unsigned long flags, this_tsc_khz; @@ -3796,6 +3819,7 @@ long kvm_arch_vm_ioctl(struct file *filp, delta = user_ns.clock - now_ns; local_irq_enable(); kvm->arch.kvmclock_offset = delta; + kvm_gen_update_masterclock(kvm); break; } case KVM_GET_CLOCK: { @@ -5804,29 +5828,6 @@ static void process_nmi(struct kvm_vcpu *vcpu) kvm_make_request(KVM_REQ_EVENT, vcpu); } -static void kvm_gen_update_masterclock(struct kvm *kvm) -{ -#ifdef CONFIG_X86_64 - int i; - struct kvm_vcpu *vcpu; - struct kvm_arch *ka = &kvm->arch; - - spin_lock(&ka->pvclock_gtod_sync_lock); - kvm_make_mclock_inprogress_request(kvm); - /* no guest entries from this point */ - pvclock_update_vm_gtod_copy(kvm); - - kvm_for_each_vcpu(i, vcpu, kvm) - set_bit(KVM_REQ_CLOCK_UPDATE, &vcpu->requests); - - /* guest entries allowed */ - kvm_for_each_vcpu(i, vcpu, kvm) - clear_bit(KVM_REQ_MCLOCK_INPROGRESS, &vcpu->requests); - - spin_unlock(&ka->pvclock_gtod_sync_lock); -#endif -} - static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu) { u64 eoi_exit_bitmap[4]; |