Convert the guest CPU's CPUID model into MSHV's format and register it
with the hypervisor. This ensures that the guest observes the correct
CPU feature set during CPUID instructions.
Signed-off-by: Magnus Kulke <magnuskulke@linux.microsoft.com>
---
target/i386/mshv/mshv-cpu.c | 199 ++++++++++++++++++++++++++++++++++++
1 file changed, 199 insertions(+)
diff --git a/target/i386/mshv/mshv-cpu.c b/target/i386/mshv/mshv-cpu.c
index dd856a2242..4208f498cd 100644
--- a/target/i386/mshv/mshv-cpu.c
+++ b/target/i386/mshv/mshv-cpu.c
@@ -377,6 +377,199 @@ int mshv_load_regs(CPUState *cpu)
return 0;
}
+static void add_cpuid_entry(GList *cpuid_entries,
+ uint32_t function, uint32_t index,
+ uint32_t eax, uint32_t ebx,
+ uint32_t ecx, uint32_t edx)
+{
+ struct hv_cpuid_entry *entry;
+
+ entry = g_malloc0(sizeof(struct hv_cpuid_entry));
+ entry->function = function;
+ entry->index = index;
+ entry->eax = eax;
+ entry->ebx = ebx;
+ entry->ecx = ecx;
+ entry->edx = edx;
+
+ cpuid_entries = g_list_append(cpuid_entries, entry);
+}
+
+static void collect_cpuid_entries(const CPUState *cpu, GList *cpuid_entries)
+{
+ X86CPU *x86_cpu = X86_CPU(cpu);
+ CPUX86State *env = &x86_cpu->env;
+ uint32_t eax, ebx, ecx, edx;
+ uint32_t leaf, subleaf;
+ size_t max_leaf = 0x1F;
+ size_t max_subleaf = 0x20;
+
+ uint32_t leaves_with_subleaves[] = {0x4, 0x7, 0xD, 0xF, 0x10};
+ int n_subleaf_leaves = ARRAY_SIZE(leaves_with_subleaves);
+
+ /* Regular leaves without subleaves */
+ for (leaf = 0; leaf <= max_leaf; leaf++) {
+ bool has_subleaves = false;
+ for (int i = 0; i < n_subleaf_leaves; i++) {
+ if (leaf == leaves_with_subleaves[i]) {
+ has_subleaves = true;
+ break;
+ }
+ }
+
+ if (!has_subleaves) {
+ cpu_x86_cpuid(env, leaf, 0, &eax, &ebx, &ecx, &edx);
+ if (eax == 0 && ebx == 0 && ecx == 0 && edx == 0) {
+ /* all zeroes indicates no more leaves */
+ continue;
+ }
+
+ add_cpuid_entry(cpuid_entries, leaf, 0, eax, ebx, ecx, edx);
+ continue;
+ }
+
+ subleaf = 0;
+ while (subleaf < max_subleaf) {
+ cpu_x86_cpuid(env, leaf, subleaf, &eax, &ebx, &ecx, &edx);
+
+ if (eax == 0 && ebx == 0 && ecx == 0 && edx == 0) {
+ /* all zeroes indicates no more leaves */
+ break;
+ }
+ add_cpuid_entry(cpuid_entries, leaf, 0, eax, ebx, ecx, edx);
+ subleaf++;
+ }
+ }
+}
+
+static int register_intercept_result_cpuid_entry(int cpu_fd,
+ uint8_t subleaf_specific,
+ uint8_t always_override,
+ struct hv_cpuid_entry *entry)
+{
+ struct hv_register_x64_cpuid_result_parameters cpuid_params = {
+ .input.eax = entry->function,
+ .input.ecx = entry->index,
+ .input.subleaf_specific = subleaf_specific,
+ .input.always_override = always_override,
+ .input.padding = 0,
+ /*
+ * With regard to masks - these are to specify bits to be overwritten
+ * The current CpuidEntry structure wouldn't allow to carry the masks
+ * in addition to the actual register values. For this reason, the
+ * masks are set to the exact values of the corresponding register bits
+ * to be registered for an overwrite. To view resulting values the
+ * hypervisor would return, HvCallGetVpCpuidValues hypercall can be
+ * used.
+ */
+ .result.eax = entry->eax,
+ .result.eax_mask = entry->eax,
+ .result.ebx = entry->ebx,
+ .result.ebx_mask = entry->ebx,
+ .result.ecx = entry->ecx,
+ .result.ecx_mask = entry->ecx,
+ .result.edx = entry->edx,
+ .result.edx_mask = entry->edx,
+ };
+ union hv_register_intercept_result_parameters parameters = {
+ .cpuid = cpuid_params,
+ };
+ struct mshv_register_intercept_result args = {
+ .intercept_type = HV_INTERCEPT_TYPE_X64_CPUID,
+ .parameters = parameters,
+ };
+ int ret;
+
+ ret = ioctl(cpu_fd, MSHV_VP_REGISTER_INTERCEPT_RESULT, &args);
+ if (ret < 0) {
+ error_report("failed to register intercept result for cpuid: %s",
+ strerror(errno));
+ return -1;
+ }
+
+ return 0;
+}
+
+static int register_intercept_result_cpuid(int cpu_fd, struct hv_cpuid *cpuid)
+{
+ int ret = 0, entry_ret;
+ struct hv_cpuid_entry *entry;
+ uint8_t subleaf_specific, always_override;
+
+ for (size_t i = 0; i < cpuid->nent; i++) {
+ entry = &cpuid->entries[i];
+
+ /* set defaults */
+ subleaf_specific = 0;
+ always_override = 1;
+
+ /* Intel */
+ /* 0xb - Extended Topology Enumeration Leaf */
+ /* 0x1f - V2 Extended Topology Enumeration Leaf */
+ /* AMD */
+ /* 0x8000_001e - Processor Topology Information */
+ /* 0x8000_0026 - Extended CPU Topology */
+ if (entry->function == 0xb
+ || entry->function == 0x1f
+ || entry->function == 0x8000001e
+ || entry->function == 0x80000026) {
+ subleaf_specific = 1;
+ always_override = 1;
+ } else if (entry->function == 0x00000001
+ || entry->function == 0x80000000
+ || entry->function == 0x80000001
+ || entry->function == 0x80000008) {
+ subleaf_specific = 0;
+ always_override = 1;
+ }
+
+ entry_ret = register_intercept_result_cpuid_entry(cpu_fd,
+ subleaf_specific,
+ always_override,
+ entry);
+ if ((entry_ret < 0) && (ret == 0)) {
+ ret = entry_ret;
+ }
+ }
+
+ return ret;
+}
+
+static int set_cpuid2(const CPUState *cpu)
+{
+ int ret;
+ size_t n_entries, cpuid_size;
+ struct hv_cpuid *cpuid;
+ struct hv_cpuid_entry *entry;
+ GList *entries = NULL;
+ int cpu_fd = mshv_vcpufd(cpu);
+
+ collect_cpuid_entries(cpu, entries);
+ n_entries = g_list_length(entries);
+
+ cpuid_size = sizeof(struct hv_cpuid)
+ + n_entries * sizeof(struct hv_cpuid_entry);
+
+ cpuid = g_malloc0(cpuid_size);
+ cpuid->nent = n_entries;
+ cpuid->padding = 0;
+
+ for (size_t i = 0; i < n_entries; i++) {
+ entry = g_list_nth_data(entries, i);
+ cpuid->entries[i] = *entry;
+ g_free(entry);
+ }
+ g_list_free(entries);
+
+ ret = register_intercept_result_cpuid(cpu_fd, cpuid);
+ g_free(cpuid);
+ if (ret < 0) {
+ return ret;
+ }
+
+ return 0;
+}
+
static void populate_hv_segment_reg(SegmentCache *seg,
hv_x64_segment_register *hv_reg)
{
@@ -671,6 +864,12 @@ int mshv_configure_vcpu(const CPUState *cpu, const struct MshvFPU *fpu,
int ret;
int cpu_fd = mshv_vcpufd(cpu);
+ ret = set_cpuid2(cpu);
+ if (ret < 0) {
+ error_report("failed to set cpuid");
+ return -1;
+ }
+
ret = set_cpu_state(cpu, fpu, xcr0);
if (ret < 0) {
error_report("failed to set cpu state");
--
2.34.1