On 2011-02-02 13:16, Glauber Costa wrote:
If the machine is stopped, we should not record two different tsc values
upon a save operation. The same problem happens with kvmclock.
But kvmclock is taking a different diretion, being now seen as a separate
device. Since this is unlikely to happen with the tsc, I am taking the
approach here of simply registering a handler for state change, and
using a per-CPUState variable that prevents double updates for the TSC.
Signed-off-by: Glauber Costa glom...@redhat.com
CC: Jan Kiszka jan.kis...@web.de
---
v2: updated tsc validation logic, as asked by Jan
---
target-i386/cpu.h |1 +
target-i386/kvm.c | 18 +-
2 files changed, 18 insertions(+), 1 deletions(-)
diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index 6d619e8..6bb2e87 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -732,6 +732,7 @@ typedef struct CPUX86State {
uint32_t sipi_vector;
uint32_t cpuid_kvm_features;
uint32_t cpuid_svm_features;
+bool tsc_valid;
/* in order to simplify APIC support, we leave this pointer to the
user */
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index ecb8405..9cc198a 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -302,6 +302,15 @@ void kvm_inject_x86_mce(CPUState *cenv, int bank,
uint64_t status,
static int _kvm_arch_init_vcpu(CPUState *env);
+static void cpu_update_state(void *opaque, int running, int reason)
+{
+CPUState *env = opaque;
+
+if (running) {
+env-tsc_valid = false;
+}
+}
+
int kvm_arch_init_vcpu(CPUState *env)
{
int r;
@@ -444,6 +453,8 @@ int kvm_arch_init_vcpu(CPUState *env)
}
#endif
+qemu_add_vm_change_state_handler(cpu_update_state, env);
+
return kvm_vcpu_ioctl(env, KVM_SET_CPUID2, cpuid_data);
}
@@ -1093,7 +1104,12 @@ static int kvm_get_msrs(CPUState *env)
msrs[n++].index = MSR_STAR;
if (kvm_has_msr_hsave_pa(env))
msrs[n++].index = MSR_VM_HSAVE_PA;
-msrs[n++].index = MSR_IA32_TSC;
+
+if (!env-tsc_valid) {
+msrs[n++].index = MSR_IA32_TSC;
+env-tsc_valid = !vm_running;
+}
+
#ifdef TARGET_X86_64
if (lm_capable_kernel) {
msrs[n++].index = MSR_CSTAR;
Yep.
Reviewed-by: Jan Kiszka jan.kis...@siemens.com
--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
