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Re: [Qemu-devel] [PATCH v4 14/18] target-i386: Add "migratable" property
From: |
Andreas Färber |
Subject: |
Re: [Qemu-devel] [PATCH v4 14/18] target-i386: Add "migratable" property to "host" CPU model |
Date: |
Thu, 15 May 2014 21:44:49 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 |
Am 30.04.2014 18:48, schrieb Eduardo Habkost:
> This flag will allow the user to choose between two modes:
> * All flags that can be enabled on the host, even if unmigratable
> (migratable=no);
> * All flags that can be enabled on the host, known to QEMU,
> and migratable (migratable=yes).
>
> The default is still migratable=false, to keep current behavior, but
> this will be changed to migratable=true by another patch.
>
> My plan was to support the "migratable" flag on all CPU classes, but
> have the default to "false" on all CPU models except "host". However,
> DeviceClass has no mechanism to allow a child class to have a different
> property default from the parent class yet, so by now only the "host"
> CPU model will support the "migratable" flag.
Just set the new default in the derived type's instance_init?
>
> Signed-off-by: Eduardo Habkost <address@hidden>
> ---
> target-i386/cpu-qom.h | 5 +++++
> target-i386/cpu.c | 52
> +++++++++++++++++++++++++++++++++++++++++++++------
> 2 files changed, 51 insertions(+), 6 deletions(-)
>
> diff --git a/target-i386/cpu-qom.h b/target-i386/cpu-qom.h
> index e9b3d57..016f90d 100644
> --- a/target-i386/cpu-qom.h
> +++ b/target-i386/cpu-qom.h
> @@ -87,6 +87,11 @@ typedef struct X86CPU {
> bool hyperv_time;
> bool check_cpuid;
> bool enforce_cpuid;
> + /* If set, only migratable flags will be accepted when "enforce" mode is
> + * used, and only migratable flags will be included in the "host"
> + * CPU model.
> + */
This belongs in the documentation comment above:
diff --git a/target-i386/cpu-qom.h b/target-i386/cpu-qom.h
index e9b3d57..aa63d3c 100644
--- a/target-i386/cpu-qom.h
+++ b/target-i386/cpu-qom.h
@@ -71,6 +71,9 @@ typedef struct X86CPUClass {
/**
* X86CPU:
* @env: #CPUX86State
+ * @migratable: If set, only migratable flags will be accepted when
"enforce"
+ * mode is used, and only migratable flags will be included in the "host"
+ * CPU model.
*
* An x86 CPU.
*/
> + bool migratable;
>
> /* if true the CPUID code directly forward host cache leaves to the
> guest */
> bool cache_info_passthrough;
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index a357056..9c30957 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -338,6 +338,7 @@ typedef struct FeatureWordInfo {
> uint32_t cpuid_ecx; /* Input ECX value for CPUID */
> int cpuid_reg; /* output register (R_* constant) */
> uint32_t tcg_features; /* Feature flags supported by TCG */
> + uint32_t unmigratable_flags; /* Feature flags known to be unmigratable */
(Here it's in .c only, so would not affect generated documentation.)
> } FeatureWordInfo;
>
> static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
> @@ -461,6 +462,30 @@ void x86_cpu_compat_disable_kvm_features(FeatureWord w,
> uint32_t features)
> kvm_default_features[w] &= ~features;
> }
>
> +/* Returns the set of feature flags that are supported and migratable by
> + * QEMU, for a given FeatureWord
> + */
> +static uint32_t x86_cpu_get_migratable_flags(FeatureWord w)
> +{
> + uint32_t r = 0;
> + int i;
> +
> + FeatureWordInfo *wi = &feature_word_info[w];
> + for (i = 0; i < 32; i++) {
> + uint32_t f = 1U << i;
> + /* If the feature name is unknown, it is not supported by QEMU yet */
> + if (!wi->feat_names[i]) {
> + continue;
> + }
> + /* Skip features known to QEMU, but explicitly marked as
> unmigratable */
> + if (wi->unmigratable_flags & f) {
> + continue;
> + }
> + r |= f;
> + }
> + return r;
> +}
> +
> void host_cpuid(uint32_t function, uint32_t count,
> uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx)
> {
> @@ -1206,6 +1231,11 @@ static int cpu_x86_fill_model_id(char *str)
>
> static X86CPUDefinition host_cpudef;
>
> +static Property x86_host_cpu_properties[] = {
host_x86_cpu_... for consistency please (specific to abstract).
> + DEFINE_PROP_BOOL("migratable", X86CPU, migratable, false),
> + DEFINE_PROP_END_OF_LIST()
> +};
> +
> /* class_init for the "host" CPU model
> *
> * This function may be called before KVM is initialized.
> @@ -1213,6 +1243,7 @@ static X86CPUDefinition host_cpudef;
> static void host_x86_cpu_class_init(ObjectClass *oc, void *data)
> {
> X86CPUClass *xcc = X86_CPU_CLASS(oc);
> + DeviceClass *dc = DEVICE_CLASS(oc);
Ordered by type hierarchy please.
> uint32_t eax = 0, ebx = 0, ecx = 0, edx = 0;
>
> host_cpuid(0x0, 0, &eax, &ebx, &ecx, &edx);
> @@ -1228,12 +1259,14 @@ static void host_x86_cpu_class_init(ObjectClass *oc,
> void *data)
> xcc->cpu_def = &host_cpudef;
> host_cpudef.cache_info_passthrough = true;
>
> + dc->props = x86_host_cpu_properties;
> /* level, xlevel, xlevel2, and the feature words are initialized on
> * instance_init, because they require KVM to be initialized.
> */
I'll swap these, as [x]level* are logically still xcc.
> }
>
> -static uint32_t x86_cpu_get_supported_feature_word(FeatureWord w);
> +static uint32_t x86_cpu_get_supported_feature_word(FeatureWord w,
> + bool migratable_only);
>
> static void host_x86_cpu_initfn(Object *obj)
> {
> @@ -1257,7 +1290,7 @@ static void host_x86_cpu_initfn(Object *obj)
>
> for (w = 0; w < FEATURE_WORDS; w++) {
> env->features[w] =
> - x86_cpu_get_supported_feature_word(w);
> + x86_cpu_get_supported_feature_word(w, cpu->migratable);
> }
> object_property_set_bool(OBJECT(cpu), true, "pmu", &error_abort);
> }
> @@ -1839,16 +1872,22 @@ CpuDefinitionInfoList
> *arch_query_cpu_definitions(Error **errp)
> return cpu_list;
> }
>
> -static uint32_t x86_cpu_get_supported_feature_word(FeatureWord w)
> +static uint32_t x86_cpu_get_supported_feature_word(FeatureWord w,
> + bool migratable_only)
> {
> FeatureWordInfo *wi = &feature_word_info[w];
> + uint32_t r;
> if (kvm_enabled()) {
> - return kvm_arch_get_supported_cpuid(kvm_state, wi->cpuid_eax,
> + r = kvm_arch_get_supported_cpuid(kvm_state, wi->cpuid_eax,
> wi->cpuid_ecx,
> wi->cpuid_reg);
Reindented.
> } else {
> - return wi->tcg_features;
> + r = wi->tcg_features;
> + }
> + if (migratable_only) {
> + r &= x86_cpu_get_migratable_flags(w);
> }
> + return r;
> }
>
> /* Filters CPU feature words based on host availability of each feature
> @@ -1862,7 +1901,8 @@ static int x86_cpu_filter_features(X86CPU *cpu)
> int rv = 0;
>
> for (w = 0; w < FEATURE_WORDS; w++) {
> - uint32_t host_feat = x86_cpu_get_supported_feature_word(w);
> + uint32_t host_feat =
> + x86_cpu_get_supported_feature_word(w, cpu->migratable);
> uint32_t requested_features = env->features[w];
> env->features[w] &= host_feat;
> cpu->filtered_features[w] = requested_features & ~env->features[w];
Regards,
Andreas
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- Re: [Qemu-devel] [PATCH v4 14/18] target-i386: Add "migratable" property to "host" CPU model,
Andreas Färber <=