On Thu, 25 Apr 2013 15:43:06 -0300
Eduardo Habkost <ehabk...@redhat.com> wrote:
> The current code handling the CPUID 0xA leaf simply forwards all data
> from GET_SUPPORTED_CPUID directly to the guest, breaking migration
> between hosts with different number of PMU counters.
>
> This patch disables this behavior, except on older machine-types (for
> compatibility) and on the "host" CPU model.
Please, make it static property and use compat properties.
Result will be simpler and much less will have to be redone/discarded after
converting to the rest to properties and sub-classes.
>
> Signed-off-by: Eduardo Habkost <ehabk...@redhat.com>
> Cc: Gleb Natapov <g...@redhat.com>
> ---
> hw/i386/pc_piix.c | 1 +
> hw/i386/pc_q35.c | 1 +
> target-i386/cpu.c | 25 ++++++++++++++++++++++++-
> target-i386/cpu.h | 7 +++++++
> 4 files changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index 9372f77..bbc7064 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -239,6 +239,7 @@ static void pc_init_pci_1_4(QEMUMachineInitArgs *args)
> {
> x86_cpu_compat_set_features("n270", FEAT_1_ECX, 0, CPUID_EXT_MOVBE);
> x86_cpu_compat_set_model("486", 0);
> + x86_cpu_enable_pmu_passthrough();
> pc_init_pci(args);
> }
>
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index fc566fd..9718e94 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -213,6 +213,7 @@ static void pc_q35_init_1_4(QEMUMachineInitArgs *args)
> {
> x86_cpu_compat_set_features("n270", FEAT_1_ECX, 0, CPUID_EXT_MOVBE);
> x86_cpu_compat_set_model("486", 0);
> + x86_cpu_enable_pmu_passthrough();
> pc_q35_init(args);
> }
>
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 4fc7527..602d00f 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -245,6 +245,16 @@ static uint32_t kvm_default_features = (1 <<
> KVM_FEATURE_CLOCKSOURCE) |
> (1 << KVM_FEATURE_PV_EOI) |
> (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT);
>
> +/* Enables passthrough of CPUID leaf 0xA by default, for compatibility with
> old
> + * machine-types.
> + */
> +static bool default_pmu_passthrough;
> +
> +void x86_cpu_enable_pmu_passthrough(void)
> +{
> + default_pmu_passthrough = true;
> +}
> +
> void disable_kvm_pv_eoi(void)
> {
> kvm_default_features &= ~(1UL << KVM_FEATURE_PV_EOI);
> @@ -375,6 +385,12 @@ typedef struct x86_def_t {
> int stepping;
> FeatureWordArray features;
> char model_id[48];
> +
> + /* Enable direct passthrough of PMU leaf from the GET_SUPPORTED_CPUID
> + * data returned by the kernel. This is not migration-safe and should
> + * never be enabled by default.
> + */
> + bool cpuid_pmu_passthrough;
> } x86_def_t;
>
> #define I486_FEATURES (CPUID_FP87 | CPUID_VME | CPUID_PSE)
> @@ -1120,6 +1136,8 @@ static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def)
> x86_cpu_def->features[FEAT_KVM] =
> kvm_arch_get_supported_cpuid(s, KVM_CPUID_FEATURES, 0, R_EAX);
>
> + x86_cpu_def->cpuid_pmu_passthrough = true;
> +
> #endif /* CONFIG_KVM */
> }
>
> @@ -1735,9 +1753,13 @@ static void cpu_x86_register(X86CPU *cpu, const char
> *name, Error **errp)
> return;
> }
>
> + /* Defaults & compat bits that are not in the builtin_x86_defs table: */
> if (kvm_enabled()) {
> def->features[FEAT_KVM] |= kvm_default_features;
> }
> + if (default_pmu_passthrough) {
> + def->cpuid_pmu_passthrough = true;
> + }
> def->features[FEAT_1_ECX] |= CPUID_EXT_HYPERVISOR;
>
> object_property_set_str(OBJECT(cpu), def->vendor, "vendor", errp);
> @@ -1755,6 +1777,7 @@ static void cpu_x86_register(X86CPU *cpu, const char
> *name, Error **errp)
> env->features[FEAT_C000_0001_EDX] = def->features[FEAT_C000_0001_EDX];
> env->features[FEAT_7_0_EBX] = def->features[FEAT_7_0_EBX];
> env->cpuid_xlevel2 = def->xlevel2;
> + env->cpuid_pmu_passthrough = def->cpuid_pmu_passthrough;
>
> object_property_set_str(OBJECT(cpu), def->model_id, "model-id", errp);
> }
> @@ -1986,7 +2009,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index,
> uint32_t count,
> break;
> case 0xA:
> /* Architectural Performance Monitoring Leaf */
> - if (kvm_enabled()) {
> + if (kvm_enabled() && env->cpuid_pmu_passthrough) {
> KVMState *s = cs->kvm_state;
>
> *eax = kvm_arch_get_supported_cpuid(s, 0xA, count, R_EAX);
> diff --git a/target-i386/cpu.h b/target-i386/cpu.h
> index 1cd5d19..12c8bf1 100644
> --- a/target-i386/cpu.h
> +++ b/target-i386/cpu.h
> @@ -843,6 +843,12 @@ typedef struct CPUX86State {
> uint32_t cpuid_vendor3;
> uint32_t cpuid_version;
> FeatureWordArray features;
> +
> + /* Enable direct passthrough of PMU leaf from the GET_SUPPORTED_CPUID
> + * data returned by the kernel. This is not migration-safe and should
> + * never be enabled by default.
> + */
> + bool cpuid_pmu_passthrough;
> uint32_t cpuid_model[12];
> uint32_t cpuid_apic_id;
>
> @@ -1258,6 +1264,7 @@ void x86_cpu_compat_set_features(const char *cpu_model,
> FeatureWord w,
> uint32_t feat_add, uint32_t feat_remove);
> void x86_cpu_compat_set_level(const char *cpu_model, uint32_t level);
> void x86_cpu_compat_set_model(const char *cpu_model, uint32_t model);
> +void x86_cpu_enable_pmu_passthrough(void);
>
>
> /* Return name of 32-bit register, from a R_* constant */
> --
> 1.8.1.4
>
--
Regards,
Igor
