qemu-kvm/kvm-i386-kvm-Move-architectural-CPUID-leaf-generation-to.patch

From 5ead79f45e8e90b7a04586c89e70cb9d0b66b730 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <sean.j.christopherson@intel.com>
Date: Thu, 29 Feb 2024 01:36:43 -0500
Subject: [PATCH 004/100] i386/kvm: Move architectural CPUID leaf generation to
 separate helper

RH-Author: Paolo Bonzini <pbonzini@redhat.com>
RH-MergeRequest: 245: SEV-SNP support
RH-Jira: RHEL-39544
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: Bandan Das <bdas@redhat.com>
RH-Acked-by: Vitaly Kuznetsov <vkuznets@redhat.com>
RH-Commit: [4/91] 06ecdbcf05ad3d658273980b114f02477d0b0475 (bonzini/rhel-qemu-kvm)

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.

For now this is just a cleanup, so keep the function static.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-ID: <20240229063726.610065-23-xiaoyao.li@intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit a5acf4f26c208a05d05ef1bde65553ce2ab5e5d0)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/kvm/kvm.c | 417 +++++++++++++++++++++---------------------
 1 file changed, 211 insertions(+), 206 deletions(-)

diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 739f33db47..5f30b649a0 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -1706,195 +1706,22 @@ static void kvm_init_nested_state(CPUX86State *env)
     }
 }
 
-int kvm_arch_init_vcpu(CPUState *cs)
+static uint32_t kvm_x86_build_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 (cs->kvm_state->xen_version) {
-#ifdef CONFIG_XEN_EMU
-        struct kvm_cpuid_entry2 *xen_max_leaf;
-
-        memcpy(signature, "XenVMMXenVMM", 12);
-
-        xen_max_leaf = c = &cpuid_data.entries[cpuid_i++];
-        c->function = kvm_base + XEN_CPUID_SIGNATURE;
-        c->eax = kvm_base + XEN_CPUID_TIME;
-        c->ebx = signature[0];
-        c->ecx = signature[1];
-        c->edx = signature[2];
-
-        c = &cpuid_data.entries[cpuid_i++];
-        c->function = kvm_base + XEN_CPUID_VENDOR;
-        c->eax = cs->kvm_state->xen_version;
-        c->ebx = 0;
-        c->ecx = 0;
-        c->edx = 0;
-
-        c = &cpuid_data.entries[cpuid_i++];
-        c->function = kvm_base + XEN_CPUID_HVM_MSR;
-        /* Number of hypercall-transfer pages */
-        c->eax = 1;
-        /* Hypercall MSR base address */
-        if (hyperv_enabled(cpu)) {
-            c->ebx = XEN_HYPERCALL_MSR_HYPERV;
-            kvm_xen_init(cs->kvm_state, c->ebx);
-        } else {
-            c->ebx = XEN_HYPERCALL_MSR;
-        }
-        c->ecx = 0;
-        c->edx = 0;
-
-        c = &cpuid_data.entries[cpuid_i++];
-        c->function = kvm_base + XEN_CPUID_TIME;
-        c->eax = ((!!tsc_is_stable_and_known(env) << 1) |
-            (!!(env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_RDTSCP) << 2));
-        /* default=0 (emulate if necessary) */
-        c->ebx = 0;
-        /* guest tsc frequency */
-        c->ecx = env->user_tsc_khz;
-        /* guest tsc incarnation (migration count) */
-        c->edx = 0;
-
-        c = &cpuid_data.entries[cpuid_i++];
-        c->function = kvm_base + XEN_CPUID_HVM;
-        xen_max_leaf->eax = kvm_base + XEN_CPUID_HVM;
-        if (cs->kvm_state->xen_version >= XEN_VERSION(4, 5)) {
-            c->function = kvm_base + XEN_CPUID_HVM;
-
-            if (cpu->xen_vapic) {
-                c->eax |= XEN_HVM_CPUID_APIC_ACCESS_VIRT;
-                c->eax |= XEN_HVM_CPUID_X2APIC_VIRT;
-            }
-
-            c->eax |= XEN_HVM_CPUID_IOMMU_MAPPINGS;
-
-            if (cs->kvm_state->xen_version >= XEN_VERSION(4, 6)) {
-                c->eax |= XEN_HVM_CPUID_VCPU_ID_PRESENT;
-                c->ebx = cs->cpu_index;
-            }
-
-            if (cs->kvm_state->xen_version >= XEN_VERSION(4, 17)) {
-                c->eax |= XEN_HVM_CPUID_UPCALL_VECTOR;
-            }
-        }
-
-        r = kvm_xen_init_vcpu(cs);
-        if (r) {
-            return r;
-        }
-
-        kvm_base += 0x100;
-#else /* CONFIG_XEN_EMU */
-        /* This should never happen as kvm_arch_init() would have died first. */
-        fprintf(stderr, "Cannot enable Xen CPUID without Xen support\n");
-        abort();
-#endif
-    } else 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++) {
+        j = 0;
         if (cpuid_i == KVM_MAX_CPUID_ENTRIES) {
-            fprintf(stderr, "unsupported level value: 0x%x\n", limit);
-            abort();
+            goto full;
         }
-        c = &cpuid_data.entries[cpuid_i++];
-
+        c = &entries[cpuid_i++];
         switch (i) {
         case 2: {
             /* Keep reading function 2 till all the input is received */
@@ -1908,11 +1735,9 @@ int kvm_arch_init_vcpu(CPUState *cs)
 
             for (j = 1; j < times; ++j) {
                 if (cpuid_i == KVM_MAX_CPUID_ENTRIES) {
-                    fprintf(stderr, "cpuid_data is full, no space for "
-                            "cpuid(eax:2):eax & 0xf = 0x%x\n", times);
-                    abort();
+                    goto full;
                 }
-                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);
@@ -1951,11 +1776,9 @@ int kvm_arch_init_vcpu(CPUState *cs)
                     continue;
                 }
                 if (cpuid_i == KVM_MAX_CPUID_ENTRIES) {
-                    fprintf(stderr, "cpuid_data is full, no space for "
-                            "cpuid(eax:0x%x,ecx:0x%x)\n", i, j);
-                    abort();
+                    goto full;
                 }
-                c = &cpuid_data.entries[cpuid_i++];
+                c = &entries[cpuid_i++];
             }
             break;
         case 0x12:
@@ -1970,11 +1793,9 @@ int kvm_arch_init_vcpu(CPUState *cs)
                 }
 
                 if (cpuid_i == KVM_MAX_CPUID_ENTRIES) {
-                    fprintf(stderr, "cpuid_data is full, no space for "
-                                "cpuid(eax:0x12,ecx:0x%x)\n", j);
-                    abort();
+                    goto full;
                 }
-                c = &cpuid_data.entries[cpuid_i++];
+                c = &entries[cpuid_i++];
             }
             break;
         case 0x7:
@@ -1991,11 +1812,9 @@ int kvm_arch_init_vcpu(CPUState *cs)
 
             for (j = 1; j <= times; ++j) {
                 if (cpuid_i == KVM_MAX_CPUID_ENTRIES) {
-                    fprintf(stderr, "cpuid_data is full, no space for "
-                                "cpuid(eax:0x%x,ecx:0x%x)\n", i, j);
-                    abort();
+                    goto full;
                 }
-                c = &cpuid_data.entries[cpuid_i++];
+                c = &entries[cpuid_i++];
                 c->function = i;
                 c->index = j;
                 c->flags = KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
@@ -2048,11 +1867,11 @@ int kvm_arch_init_vcpu(CPUState *cs)
     cpu_x86_cpuid(env, 0x80000000, 0, &limit, &unused, &unused, &unused);
 
     for (i = 0x80000000; i <= limit; i++) {
+        j = 0;
         if (cpuid_i == KVM_MAX_CPUID_ENTRIES) {
-            fprintf(stderr, "unsupported xlevel value: 0x%x\n", limit);
-            abort();
+            goto full;
         }
-        c = &cpuid_data.entries[cpuid_i++];
+        c = &entries[cpuid_i++];
 
         switch (i) {
         case 0x8000001d:
@@ -2067,11 +1886,9 @@ int kvm_arch_init_vcpu(CPUState *cs)
                     break;
                 }
                 if (cpuid_i == KVM_MAX_CPUID_ENTRIES) {
-                    fprintf(stderr, "cpuid_data is full, no space for "
-                            "cpuid(eax:0x%x,ecx:0x%x)\n", i, j);
-                    abort();
+                    goto full;
                 }
-                c = &cpuid_data.entries[cpuid_i++];
+                c = &entries[cpuid_i++];
             }
             break;
         default:
@@ -2094,11 +1911,11 @@ int kvm_arch_init_vcpu(CPUState *cs)
         cpu_x86_cpuid(env, 0xC0000000, 0, &limit, &unused, &unused, &unused);
 
         for (i = 0xC0000000; i <= limit; i++) {
+            j = 0;
             if (cpuid_i == KVM_MAX_CPUID_ENTRIES) {
-                fprintf(stderr, "unsupported xlevel2 value: 0x%x\n", limit);
-                abort();
+                goto full;
             }
-            c = &cpuid_data.entries[cpuid_i++];
+            c = &entries[cpuid_i++];
 
             c->function = i;
             c->flags = 0;
@@ -2106,6 +1923,194 @@ int kvm_arch_init_vcpu(CPUState *cs)
         }
     }
 
+    return cpuid_i;
+
+full:
+    fprintf(stderr, "cpuid_data is full, no space for "
+            "cpuid(eax:0x%x,ecx:0x%x)\n", i, j);
+    abort();
+}
+
+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 (cs->kvm_state->xen_version) {
+#ifdef CONFIG_XEN_EMU
+        struct kvm_cpuid_entry2 *xen_max_leaf;
+
+        memcpy(signature, "XenVMMXenVMM", 12);
+
+        xen_max_leaf = c = &cpuid_data.entries[cpuid_i++];
+        c->function = kvm_base + XEN_CPUID_SIGNATURE;
+        c->eax = kvm_base + XEN_CPUID_TIME;
+        c->ebx = signature[0];
+        c->ecx = signature[1];
+        c->edx = signature[2];
+
+        c = &cpuid_data.entries[cpuid_i++];
+        c->function = kvm_base + XEN_CPUID_VENDOR;
+        c->eax = cs->kvm_state->xen_version;
+        c->ebx = 0;
+        c->ecx = 0;
+        c->edx = 0;
+
+        c = &cpuid_data.entries[cpuid_i++];
+        c->function = kvm_base + XEN_CPUID_HVM_MSR;
+        /* Number of hypercall-transfer pages */
+        c->eax = 1;
+        /* Hypercall MSR base address */
+        if (hyperv_enabled(cpu)) {
+            c->ebx = XEN_HYPERCALL_MSR_HYPERV;
+            kvm_xen_init(cs->kvm_state, c->ebx);
+        } else {
+            c->ebx = XEN_HYPERCALL_MSR;
+        }
+        c->ecx = 0;
+        c->edx = 0;
+
+        c = &cpuid_data.entries[cpuid_i++];
+        c->function = kvm_base + XEN_CPUID_TIME;
+        c->eax = ((!!tsc_is_stable_and_known(env) << 1) |
+            (!!(env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_RDTSCP) << 2));
+        /* default=0 (emulate if necessary) */
+        c->ebx = 0;
+        /* guest tsc frequency */
+        c->ecx = env->user_tsc_khz;
+        /* guest tsc incarnation (migration count) */
+        c->edx = 0;
+
+        c = &cpuid_data.entries[cpuid_i++];
+        c->function = kvm_base + XEN_CPUID_HVM;
+        xen_max_leaf->eax = kvm_base + XEN_CPUID_HVM;
+        if (cs->kvm_state->xen_version >= XEN_VERSION(4, 5)) {
+            c->function = kvm_base + XEN_CPUID_HVM;
+
+            if (cpu->xen_vapic) {
+                c->eax |= XEN_HVM_CPUID_APIC_ACCESS_VIRT;
+                c->eax |= XEN_HVM_CPUID_X2APIC_VIRT;
+            }
+
+            c->eax |= XEN_HVM_CPUID_IOMMU_MAPPINGS;
+
+            if (cs->kvm_state->xen_version >= XEN_VERSION(4, 6)) {
+                c->eax |= XEN_HVM_CPUID_VCPU_ID_PRESENT;
+                c->ebx = cs->cpu_index;
+            }
+
+            if (cs->kvm_state->xen_version >= XEN_VERSION(4, 17)) {
+                c->eax |= XEN_HVM_CPUID_UPCALL_VECTOR;
+            }
+        }
+
+        r = kvm_xen_init_vcpu(cs);
+        if (r) {
+            return r;
+        }
+
+        kvm_base += 0x100;
+#else /* CONFIG_XEN_EMU */
+        /* This should never happen as kvm_arch_init() would have died first. */
+        fprintf(stderr, "Cannot enable Xen CPUID without Xen support\n");
+        abort();
+#endif
+    } else 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_build_cpuid(env, cpuid_data.entries, cpuid_i);
     cpuid_data.cpuid.nent = cpuid_i;
 
     if (((env->cpuid_version >> 8)&0xF) >= 6
-- 
2.39.3