[PATCH v1 12/40] i386/kvm: Move architectural CPUID leaf generation to separate helper

Xiaoyao Li
2022-08-02T07:49:15Z

From: Sean Christopherson <sean.j.christopherson@intel.com>

Move the architectural (for lack of a better term) CPUID leaf generation
to a separate helper so that the generation code can be reused by TDX,
which needs to generate a canonical VM-scoped configuration.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
target/i386/kvm/kvm.c | 220 +++++++++++++++++++------------------
target/i386/kvm/kvm_i386.h | 3 +
2 files changed, 118 insertions(+), 105 deletions(-)

diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 9930902ae890..9c0d5be5cc23 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -1728,115 +1728,21 @@ static void kvm_init_xsave(CPUX86State *env)
env->xsave_buf_len);
}

-int kvm_arch_init_vcpu(CPUState *cs)
+uint32_t kvm_x86_arch_cpuid(CPUX86State *env, struct kvm_cpuid_entry2 *entries,
+ uint32_t cpuid_i)
{
- struct {
- struct kvm_cpuid2 cpuid;
- struct kvm_cpuid_entry2 entries[KVM_MAX_CPUID_ENTRIES];
- } cpuid_data;
- /*
- * The kernel defines these structs with padding fields so there
- * should be no extra padding in our cpuid_data struct.
- */
- QEMU_BUILD_BUG_ON(sizeof(cpuid_data) !=
- sizeof(struct kvm_cpuid2) +
- sizeof(struct kvm_cpuid_entry2) * KVM_MAX_CPUID_ENTRIES);
-
- X86CPU *cpu = X86_CPU(cs);
- CPUX86State *env = &cpu->env;
- uint32_t limit, i, j, cpuid_i;
+ uint32_t limit, i, j;
uint32_t unused;
struct kvm_cpuid_entry2 *c;
- uint32_t signature[3];
- int kvm_base = KVM_CPUID_SIGNATURE;
- int max_nested_state_len;
- int r;
- Error *local_err = NULL;
-
- memset(&cpuid_data, 0, sizeof(cpuid_data));
-
- cpuid_i = 0;
-
- has_xsave2 = kvm_check_extension(cs->kvm_state, KVM_CAP_XSAVE2);
-
- r = kvm_arch_set_tsc_khz(cs);
- if (r < 0) {
- return r;
- }
-
- /* vcpu's TSC frequency is either specified by user, or following
- * the value used by KVM if the former is not present. In the
- * latter case, we query it from KVM and record in env->tsc_khz,
- * so that vcpu's TSC frequency can be migrated later via this field.
- */
- if (!env->tsc_khz) {
- r = kvm_check_extension(cs->kvm_state, KVM_CAP_GET_TSC_KHZ) ?
- kvm_vcpu_ioctl(cs, KVM_GET_TSC_KHZ) :
- -ENOTSUP;
- if (r > 0) {
- env->tsc_khz = r;
- }
- }
-
- env->apic_bus_freq = KVM_APIC_BUS_FREQUENCY;
-
- /*
- * kvm_hyperv_expand_features() is called here for the second time in case
- * KVM_CAP_SYS_HYPERV_CPUID is not supported. While we can't possibly handle
- * 'query-cpu-model-expansion' in this case as we don't have a KVM vCPU to
- * check which Hyper-V enlightenments are supported and which are not, we
- * can still proceed and check/expand Hyper-V enlightenments here so legacy
- * behavior is preserved.
- */
- if (!kvm_hyperv_expand_features(cpu, &local_err)) {
- error_report_err(local_err);
- return -ENOSYS;
- }
-
- if (hyperv_enabled(cpu)) {
- r = hyperv_init_vcpu(cpu);
- if (r) {
- return r;
- }
-
- cpuid_i = hyperv_fill_cpuids(cs, cpuid_data.entries);
- kvm_base = KVM_CPUID_SIGNATURE_NEXT;
- has_msr_hv_hypercall = true;
- }
-
- if (cpu->expose_kvm) {
- memcpy(signature, "KVMKVMKVM\0\0\0", 12);
- c = &cpuid_data.entries[cpuid_i++];
- c->function = KVM_CPUID_SIGNATURE | kvm_base;
- c->eax = KVM_CPUID_FEATURES | kvm_base;
- c->ebx = signature[0];
- c->ecx = signature[1];
- c->edx = signature[2];
-
- c = &cpuid_data.entries[cpuid_i++];
- c->function = KVM_CPUID_FEATURES | kvm_base;
- c->eax = env->features[FEAT_KVM];
- c->edx = env->features[FEAT_KVM_HINTS];
- }

cpu_x86_cpuid(env, 0, 0, &limit, &unused, &unused, &unused);

- if (cpu->kvm_pv_enforce_cpuid) {
- r = kvm_vcpu_enable_cap(cs, KVM_CAP_ENFORCE_PV_FEATURE_CPUID, 0, 1);
- if (r < 0) {
- fprintf(stderr,
- "failed to enable KVM_CAP_ENFORCE_PV_FEATURE_CPUID: %s",
- strerror(-r));
- abort();
- }
- }
-
for (i = 0; i <= limit; i++) {
if (cpuid_i == KVM_MAX_CPUID_ENTRIES) {
fprintf(stderr, "unsupported level value: 0x%x\n", limit);
abort();
}
- c = &cpuid_data.entries[cpuid_i++];
+ c = &entries[cpuid_i++];

switch (i) {
case 2: {
@@ -1855,7 +1761,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
"cpuid(eax:2):eax & 0xf = 0x%x\n", times);
abort();
}
- c = &cpuid_data.entries[cpuid_i++];
+ c = &entries[cpuid_i++];
c->function = i;
c->flags = KVM_CPUID_FLAG_STATEFUL_FUNC;
cpu_x86_cpuid(env, i, 0, &c->eax, &c->ebx, &c->ecx, &c->edx);
@@ -1901,7 +1807,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
"cpuid(eax:0x%x,ecx:0x%x)\n", i, j);
abort();
}
- c = &cpuid_data.entries[cpuid_i++];
+ c = &entries[cpuid_i++];
}
break;
case 0x7:
@@ -1921,7 +1827,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
"cpuid(eax:0x12,ecx:0x%x)\n", j);
abort();
}
- c = &cpuid_data.entries[cpuid_i++];
+ c = &entries[cpuid_i++];
}
break;
case 0x14:
@@ -1941,7 +1847,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
"cpuid(eax:0x%x,ecx:0x%x)\n", i, j);
abort();
}
- c = &cpuid_data.entries[cpuid_i++];
+ c = &entries[cpuid_i++];
c->function = i;
c->index = j;
c->flags = KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
@@ -1998,7 +1904,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
fprintf(stderr, "unsupported xlevel value: 0x%x\n", limit);
abort();
}
- c = &cpuid_data.entries[cpuid_i++];
+ c = &entries[cpuid_i++];

switch (i) {
case 0x8000001d:
@@ -2017,7 +1923,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
"cpuid(eax:0x%x,ecx:0x%x)\n", i, j);
abort();
}
- c = &cpuid_data.entries[cpuid_i++];
+ c = &entries[cpuid_i++];
}
break;
default:
@@ -2044,7 +1950,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
fprintf(stderr, "unsupported xlevel2 value: 0x%x\n", limit);
abort();
}
- c = &cpuid_data.entries[cpuid_i++];
+ c = &entries[cpuid_i++];

c->function = i;
c->flags = 0;
@@ -2052,6 +1958,110 @@ int kvm_arch_init_vcpu(CPUState *cs)
}
}

+ return cpuid_i;
+}
+
+int kvm_arch_init_vcpu(CPUState *cs)
+{
+ struct {
+ struct kvm_cpuid2 cpuid;
+ struct kvm_cpuid_entry2 entries[KVM_MAX_CPUID_ENTRIES];
+ } cpuid_data;
+ /*
+ * The kernel defines these structs with padding fields so there
+ * should be no extra padding in our cpuid_data struct.
+ */
+ QEMU_BUILD_BUG_ON(sizeof(cpuid_data) !=
+ sizeof(struct kvm_cpuid2) +
+ sizeof(struct kvm_cpuid_entry2) * KVM_MAX_CPUID_ENTRIES);
+
+ X86CPU *cpu = X86_CPU(cs);
+ CPUX86State *env = &cpu->env;
+ uint32_t cpuid_i;
+ struct kvm_cpuid_entry2 *c;
+ uint32_t signature[3];
+ int kvm_base = KVM_CPUID_SIGNATURE;
+ int max_nested_state_len;
+ int r;
+ Error *local_err = NULL;
+
+ memset(&cpuid_data, 0, sizeof(cpuid_data));
+
+ cpuid_i = 0;
+
+ has_xsave2 = kvm_check_extension(cs->kvm_state, KVM_CAP_XSAVE2);
+
+ r = kvm_arch_set_tsc_khz(cs);
+ if (r < 0) {
+ return r;
+ }
+
+ /* vcpu's TSC frequency is either specified by user, or following
+ * the value used by KVM if the former is not present. In the
+ * latter case, we query it from KVM and record in env->tsc_khz,
+ * so that vcpu's TSC frequency can be migrated later via this field.
+ */
+ if (!env->tsc_khz) {
+ r = kvm_check_extension(cs->kvm_state, KVM_CAP_GET_TSC_KHZ) ?
+ kvm_vcpu_ioctl(cs, KVM_GET_TSC_KHZ) :
+ -ENOTSUP;
+ if (r > 0) {
+ env->tsc_khz = r;
+ }
+ }
+
+ env->apic_bus_freq = KVM_APIC_BUS_FREQUENCY;
+
+ /*
+ * kvm_hyperv_expand_features() is called here for the second time in case
+ * KVM_CAP_SYS_HYPERV_CPUID is not supported. While we can't possibly handle
+ * 'query-cpu-model-expansion' in this case as we don't have a KVM vCPU to
+ * check which Hyper-V enlightenments are supported and which are not, we
+ * can still proceed and check/expand Hyper-V enlightenments here so legacy
+ * behavior is preserved.
+ */
+ if (!kvm_hyperv_expand_features(cpu, &local_err)) {
+ error_report_err(local_err);
+ return -ENOSYS;
+ }
+
+ if (hyperv_enabled(cpu)) {
+ r = hyperv_init_vcpu(cpu);
+ if (r) {
+ return r;
+ }
+
+ cpuid_i = hyperv_fill_cpuids(cs, cpuid_data.entries);
+ kvm_base = KVM_CPUID_SIGNATURE_NEXT;
+ has_msr_hv_hypercall = true;
+ }
+
+ if (cpu->expose_kvm) {
+ memcpy(signature, "KVMKVMKVM\0\0\0", 12);
+ c = &cpuid_data.entries[cpuid_i++];
+ c->function = KVM_CPUID_SIGNATURE | kvm_base;
+ c->eax = KVM_CPUID_FEATURES | kvm_base;
+ c->ebx = signature[0];
+ c->ecx = signature[1];
+ c->edx = signature[2];
+
+ c = &cpuid_data.entries[cpuid_i++];
+ c->function = KVM_CPUID_FEATURES | kvm_base;
+ c->eax = env->features[FEAT_KVM];
+ c->edx = env->features[FEAT_KVM_HINTS];
+ }
+
+ if (cpu->kvm_pv_enforce_cpuid) {
+ r = kvm_vcpu_enable_cap(cs, KVM_CAP_ENFORCE_PV_FEATURE_CPUID, 0, 1);
+ if (r < 0) {
+ fprintf(stderr,
+ "failed to enable KVM_CAP_ENFORCE_PV_FEATURE_CPUID: %s",
+ strerror(-r));
+ abort();
+ }
+ }
+
+ cpuid_i = kvm_x86_arch_cpuid(env, cpuid_data.entries, cpuid_i);
cpuid_data.cpuid.nent = cpuid_i;

if (((env->cpuid_version >> 8)&0xF) >= 6
diff --git a/target/i386/kvm/kvm_i386.h b/target/i386/kvm/kvm_i386.h
index 6b24ab2a7813..c77dd7a95a7c 100644
--- a/target/i386/kvm/kvm_i386.h
+++ b/target/i386/kvm/kvm_i386.h
@@ -26,6 +26,9 @@
#define kvm_ioapic_in_kernel() \
(kvm_irqchip_in_kernel() && !kvm_irqchip_is_split())

+uint32_t kvm_x86_arch_cpuid(CPUX86State *env, struct kvm_cpuid_entry2 *entries,
+ uint32_t cpuid_i);
+
#else

#define kvm_pit_in_kernel() 0
--
2.27.0