diff options
| author | Liang Li <liang.z.li@intel.com> | 2015-11-05 11:51:03 +0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2015-11-05 11:28:10 +0100 |
| commit | 0fd7e098db30e302d27920487f0afec33be8982a (patch) | |
| tree | 87cfe5cc1dc319430ae507e6ecf76199b349e9b3 /hw/i386 | |
| parent | b553a0428014636bce4951098e97c60dc18a83ed (diff) | |
kvmclock: add a new function to update env->tsc.
The commit 317b0a6d8 fixed an issue which caused by the outdated
env->tsc value, but the fix lead to 'cpu_synchronize_all_states()'
called twice during live migration. The 'cpu_synchronize_all_states()'
takes about 130us for a VM which has 4 vcpus, it's a bit expensive.
Synchronize the whole CPU context just for updating env->tsc is too
wasting, this patch use a new function to update the env->tsc.
Comparing to 'cpu_synchronize_all_states()', it only takes about 20us.
Signed-off-by: Liang Li <liang.z.li@intel.com>
Message-Id: <1446695464-27116-2-git-send-email-liang.z.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'hw/i386')
| -rw-r--r-- | hw/i386/kvm/clock.c | 18 |
1 files changed, 2 insertions, 16 deletions
diff --git a/hw/i386/kvm/clock.c b/hw/i386/kvm/clock.c index efdf165848..0593a3f1f5 100644 --- a/hw/i386/kvm/clock.c +++ b/hw/i386/kvm/clock.c @@ -17,7 +17,7 @@ #include "qemu/host-utils.h" #include "sysemu/sysemu.h" #include "sysemu/kvm.h" -#include "sysemu/cpus.h" +#include "kvm_i386.h" #include "hw/sysbus.h" #include "hw/kvm/clock.h" @@ -125,21 +125,7 @@ static void kvmclock_vm_state_change(void *opaque, int running, return; } - cpu_synchronize_all_states(); - /* In theory, the cpu_synchronize_all_states() call above wouldn't - * affect the rest of the code, as the VCPU state inside CPUState - * is supposed to always match the VCPU state on the kernel side. - * - * In practice, calling cpu_synchronize_state() too soon will load the - * kernel-side APIC state into X86CPU.apic_state too early, APIC state - * won't be reloaded later because CPUState.vcpu_dirty==true, and - * outdated APIC state may be migrated to another host. - * - * The real fix would be to make sure outdated APIC state is read - * from the kernel again when necessary. While this is not fixed, we - * need the cpu_clean_all_dirty() call below. - */ - cpu_clean_all_dirty(); + kvm_synchronize_all_tsc(); ret = kvm_vm_ioctl(kvm_state, KVM_GET_CLOCK, &data); if (ret < 0) { |