We can't simply expose the GET_SUPPORTED_CPUID results directly to the
guest, or the resulting guest-visible CPUID bits may change under the
guest's feet when we live-migrate.
We still have to implement proper per-machine-type migration
compatibility bits, but this at least is a workaround for cases where PV
EOI would be silently enabled after a host kernel upgrade.
We also have to implement proper check/warnings about unsupported bits
when using "-cpu check" or "-cpu enforce", because the default bits may
be silently disabled if the host kernel doesn't support them.
Signed-off-by: Eduardo Habkost <ehabkost@xxxxxxxxxx>
---
target-i386/cpu.c | 18 +++++++++++++++++-
target-i386/cpu.h | 10 ++++++++++
2 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 120a2e3..52042f0 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -283,6 +283,21 @@ typedef struct x86_def_t {
CPUID_EXT3_CR8LEG | CPUID_EXT3_ABM | CPUID_EXT3_SSE4A)
#define TCG_SVM_FEATURES 0
+
+/* List of KVM features we (try to) enable by default
+ *
+ * CPUID_KVM_PV_EOI is not enabled until we have proper per-machine-type
+ * migration compatibility support
+ *
+ * CPUID_KVM_MMU is not enabled because it is deprecated.
+ */
+#define DEFAULT_KVM_FEATURES (CPUID_KVM_CLOCKSOURCE | \
+ CPUID_KVM_KVM_NOP_IO_DELAY | \
+ CPUID_KVM_CLOCKSOURCE2 | \
+ CPUID_KVM_KVM_ASYNC_PF | \
+ CPUID_KVM_STEAL_TIME | \
+ CPUID_KVM_CLOCKSOURCE_STABLE_BIT)
+
/* maintains list of cpu model definitions
*/
static x86_def_t *x86_defs = {NULL};
@@ -887,7 +902,8 @@ static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, const char *cpu_model)
memcpy(x86_cpu_def, def, sizeof(*def));
}
- plus_kvm_features = ~0; /* not supported bits will be filtered out later */
+ /* not supported bits will be filtered out later */
+ plus_kvm_features = DEFAULT_KVM_FEATURES;
add_flagname_to_bitmaps("hypervisor", &plus_features,
&plus_ext_features, &plus_ext2_features, &plus_ext3_features,
diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index 60f9e97..5ce4baf 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -440,6 +440,16 @@
#define CPUID_SVM_PAUSEFILTER (1 << 10)
#define CPUID_SVM_PFTHRESHOLD (1 << 12)
+/* CPUID[4000_0001h].EAX bits: */
+#define CPUID_KVM_CLOCKSOURCE (1 << 0)
+#define CPUID_KVM_KVM_NOP_IO_DELAY (1 << 1)
+#define CPUID_KVM_MMU (1 << 2)
+#define CPUID_KVM_CLOCKSOURCE2 (1 << 3)
+#define CPUID_KVM_KVM_ASYNC_PF (1 << 4)
+#define CPUID_KVM_STEAL_TIME (1 << 5)
+#define CPUID_KVM_KVM_PV_EOI (1 << 6)
+#define CPUID_KVM_CLOCKSOURCE_STABLE_BIT (1 << 24)
+
#define CPUID_VENDOR_INTEL_1 0x756e6547 /* "Genu" */
#define CPUID_VENDOR_INTEL_2 0x49656e69 /* "ineI" */
#define CPUID_VENDOR_INTEL_3 0x6c65746e /* "ntel" */
--
1.7.11.4
--
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