[PATCH 4/4] kvm: Trim cpu features not supported by kvm

Avi Kivity
2009-05-03T14:04:13Z

Remove cpu features that are not supported by kvm from the cpuid features
reported to the guest.

Signed-off-by: Avi Kivity <avi@redhat.com>
---
target-i386/helper.c | 30 ++++++++++++++++++++++++++++++
1 files changed, 30 insertions(+), 0 deletions(-)

diff --git a/target-i386/helper.c b/target-i386/helper.c
index 0c91133..bdf242b 100644
--- a/target-i386/helper.c
+++ b/target-i386/helper.c
@@ -93,6 +93,21 @@ static void add_flagname_to_bitmaps(char *flagname, uint32_t *features,
}
}

+static void kvm_trim_features(uint32_t *features, uint32_t supported,
+ const char *names[])
+{
+ int i;
+ uint32_t mask;
+
+ for (i = 0; i < 32; ++i) {
+ mask = 1U << i;
+ if ((*features & mask) && !(supported & mask)) {
+ printf("Processor feature %s not supported by kvm\n", names[i]);
+ *features &= ~mask;
+ }
+ }
+}
+
typedef struct x86_def_t {
const char *name;
uint32_t level;
@@ -1699,5 +1714,20 @@ CPUX86State *cpu_x86_init(const char *cpu_model)

qemu_init_vcpu(env);

+ if (kvm_enabled()) {
+ kvm_trim_features(&env->cpuid_features,
+ kvm_arch_get_supported_cpuid(env, 1, R_EDX),
+ feature_name);
+ kvm_trim_features(&env->cpuid_ext_features,
+ kvm_arch_get_supported_cpuid(env, 1, R_ECX),
+ ext_feature_name);
+ kvm_trim_features(&env->cpuid_ext2_features,
+ kvm_arch_get_supported_cpuid(env, 0x80000001, R_EDX),
+ ext2_feature_name);
+ kvm_trim_features(&env->cpuid_ext3_features,
+ kvm_arch_get_supported_cpuid(env, 0x80000001, R_ECX),
+ ext3_feature_name);
+ }
+
return env;
}
--
1.6.1.1