On Tue, Apr 22, 2014 at 04:10:44PM -0300, Marcelo Tosatti wrote:
> Invariant TSC documentation mentions that "invariant TSC will run at a
> constant rate in all ACPI P-, C-. and T-states".
>
> This is not the case if migration to a host with different TSC frequency
> is allowed, or if savevm is performed. So block migration/savevm.
>
> Also do not expose invariant tsc flag by default.
>
> Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
>
> Index: qemu-invariant-tsc/target-i386/kvm.c
> ===================================================================
> --- qemu-invariant-tsc.orig/target-i386/kvm.c
> +++ qemu-invariant-tsc/target-i386/kvm.c
> @@ -33,6 +33,8 @@
> #include "exec/ioport.h"
> #include <asm/hyperv.h>
> #include "hw/pci/pci.h"
> +#include "migration/migration.h"
> +#include "qapi/qmp/qerror.h"
>
> //#define DEBUG_KVM
>
> @@ -447,6 +449,8 @@ static bool hyperv_enabled(X86CPU *cpu)
> cpu->hyperv_relaxed_timing);
> }
>
> +Error *invtsc_mig_blocker;
> +
> #define KVM_MAX_CPUID_ENTRIES 100
>
> int kvm_arch_init_vcpu(CPUState *cs)
> @@ -702,6 +706,16 @@ int kvm_arch_init_vcpu(CPUState *cs)
> !!(c->ecx & CPUID_EXT_SMX);
> }
>
> + c = cpuid_find_entry(&cpuid_data.cpuid, 0x80000007, 0);
> + if (c && (c->edx & 1<<8)) {
> + /* for migration */
> + invtsc_mig_blocker = NULL;
> + error_set(&invtsc_mig_blocker, QERR_MIGRATION_NOT_SUPPORTED, "cpu");
> + migrate_add_blocker(invtsc_mig_blocker);
> + /* for savevm */
> + vmstate_x86_cpu.unmigratable = 1;
> + }
Oops, broken with multiple CPUs. Please review the rest.
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