expose host CPU features to guests

danken-atKUWr5tajBWk0Htik3J/w
2007-09-05T17:45:30Z

Hi,

It's a pity not to use a host CPU feature if it is available. This patch
exposes host CPU features to guests. It allows fine-tuning the presented
features from the command-line.

The code could use some serious clean ups, but I think it is interesting
enough right now. I'd be happy to hear your opinion and suggestions.
The diff are done against qemu cvs. I tried it with kvm, but I thinkg it
should be useful also for kqemu.

Regards,

Dan.

Index: vl.c
===================================================================
RCS file: /sources/qemu/qemu/vl.c,v
retrieving revision 1.336
diff -u -p -r1.336 vl.c
--- vl.c 28 Aug 2007 22:21:40 -0000 1.336
+++ vl.c 5 Sep 2007 15:48:10 -0000
@@ -6575,12 +6575,24 @@ int qemu_register_machine(QEMUMachine *m
return 0;
}

+const char *machine_flavor = 0;
+
QEMUMachine *find_machine(const char *name)
{
QEMUMachine *m;

+ int n;
+ machine_flavor = strchr(name, ',');
+ if (machine_flavor) {
+ n = machine_flavor - name;
+ machine_flavor++;
+ } else {
+ n = strlen(name);
+ machine_flavor = "";
+ }
+
for(m = first_machine; m != NULL; m = m->next) {
- if (!strcmp(m->name, name))
+ if (!strncmp(m->name, name, n))
return m;
}
return NULL;
@@ -7343,6 +7355,7 @@ static void read_passwords(void)
void register_machines(void)
{
#if defined(TARGET_I386)
+ qemu_register_machine(&host_pc_machine);
qemu_register_machine(&pc_machine);
qemu_register_machine(&isapc_machine);
#elif defined(TARGET_PPC)
Index: vl.h
===================================================================
RCS file: /sources/qemu/qemu/vl.h,v
retrieving revision 1.264
diff -u -p -r1.264 vl.h
--- vl.h 26 Aug 2007 17:46:00 -0000 1.264
+++ vl.h 5 Sep 2007 15:48:10 -0000
@@ -1156,6 +1156,7 @@ void piix4_smbus_register_device(SMBusDe
void acpi_bios_init(void);

/* pc.c */
+extern QEMUMachine host_pc_machine;
extern QEMUMachine pc_machine;
extern QEMUMachine isapc_machine;
extern int fd_bootchk;
Index: hw/pc.c
===================================================================
RCS file: /sources/qemu/qemu/hw/pc.c,v
retrieving revision 1.83
diff -u -p -r1.83 pc.c
--- hw/pc.c 26 Aug 2007 17:51:39 -0000 1.83
+++ hw/pc.c 5 Sep 2007 15:48:10 -0000
@@ -965,6 +965,28 @@ static void pc_init_isa(int ram_size, in
initrd_filename, 0);
}

+int use_hostlike_cpu = 0;
+
+static void pc_init_hostlike(ram_addr_t ram_size, int vga_ram_size, int boot_device,
+ DisplayState *ds, const char **fd_filename,
+ int snapshot,
+ const char *kernel_filename,
+ const char *kernel_cmdline,
+ const char *initrd_filename)
+{
+ use_hostlike_cpu = 1;
+ pc_init1(ram_size, vga_ram_size, boot_device,
+ ds, fd_filename, snapshot,
+ kernel_filename, kernel_cmdline,
+ initrd_filename, 1);
+}
+
+QEMUMachine host_pc_machine = {
+ "host",
+ "Standard PC with host-like CPU",
+ pc_init_hostlike,
+};
+
QEMUMachine pc_machine = {
"pc",
"Standard PC",
Index: target-i386/cpu.h
===================================================================
RCS file: /sources/qemu/qemu/target-i386/cpu.h,v
retrieving revision 1.45
diff -u -p -r1.45 cpu.h
--- target-i386/cpu.h 11 Jul 2007 22:48:58 -0000 1.45
+++ target-i386/cpu.h 5 Sep 2007 15:48:10 -0000
@@ -267,21 +267,44 @@
#define CPUID_CMOV (1 << 15)
#define CPUID_PAT (1 << 16)
#define CPUID_PSE36 (1 << 17)
+#define CPUID_PN (1 << 18)
#define CPUID_CLFLUSH (1 << 19)
-/* ... */
+#define CPUID_DTS (1 << 21)
+#define CPUID_ACPI (1 << 22)
#define CPUID_MMX (1 << 23)
#define CPUID_FXSR (1 << 24)
#define CPUID_SSE (1 << 25)
#define CPUID_SSE2 (1 << 26)
+#define CPUID_SS (1 << 27)
+#define CPUID_HT (1 << 28)
+#define CPUID_TM (1 << 29)
+#define CPUID_IA64 (1 << 30)
+#define CPUID_PBE (1 << 31)

#define CPUID_EXT_SSE3 (1 << 0)
#define CPUID_EXT_MONITOR (1 << 3)
+#define CPUID_EXT_DSCPL (1 << 4)
+#define CPUID_EXT_VMX (1 << 5)
+#define CPUID_EXT_SMX (1 << 6)
+#define CPUID_EXT_EST (1 << 7)
+#define CPUID_EXT_TM2 (1 << 8)
+#define CPUID_EXT_SSSE3 (1 << 9)
+#define CPUID_EXT_CID (1 << 10)
#define CPUID_EXT_CX16 (1 << 13)
+#define CPUID_EXT_XTPR (1 << 14)
+#define CPUID_EXT_DCA (1 << 17)
+#define CPUID_EXT_POPCNT (1 << 22)

#define CPUID_EXT2_SYSCALL (1 << 11)
+#define CPUID_EXT2_MP (1 << 19)
#define CPUID_EXT2_NX (1 << 20)
+#define CPUID_EXT2_MMXEXT (1 << 22)
#define CPUID_EXT2_FFXSR (1 << 25)
+#define CPUID_EXT2_PDPE1GB (1 << 26)
+#define CPUID_EXT2_RDTSCP (1 << 27)
#define CPUID_EXT2_LM (1 << 29)
+#define CPUID_EXT2_3DNOWEXT (1 << 30)
+#define CPUID_EXT2_3DNOW (1 << 31)

#define EXCP00_DIVZ 0
#define EXCP01_SSTP 1
Index: target-i386/helper2.c
===================================================================
RCS file: /sources/qemu/qemu/target-i386/helper2.c,v
retrieving revision 1.48
diff -u -p -r1.48 helper2.c
--- target-i386/helper2.c 31 Jul 2007 23:09:18 -0000 1.48
+++ target-i386/helper2.c 5 Sep 2007 15:48:10 -0000
@@ -45,6 +45,272 @@ int modify_ldt(int func, void *ptr, unsi
#endif
#endif /* USE_CODE_COPY */

+/* x86_cap_flags taken from Linux's arch/i386/kernel/cpu/proc.c */
+static const char * const x86_cap_flags[] = {
+ /* Intel-defined */
+ "fpu", "vme", "de", "pse", "tsc", "msr", "pae", "mce",
+ "cx8", "apic", NULL, "sep", "mtrr", "pge", "mca", "cmov",
+ "pat", "pse36", "pn", "clflush", NULL, "dts", "acpi", "mmx",
+ "fxsr", "sse", "sse2", "ss", "ht", "tm", "ia64", "pbe",
+
+ /* AMD-defined */
+ NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+ NULL, NULL, NULL, "syscall", NULL, NULL, NULL, NULL,
+ NULL, NULL, NULL, "mp", "nx", NULL, "mmxext", NULL,
+ NULL, "fxsr_opt", "pdpe1gb", "rdtscp", NULL, "lm", "3dnowext", "3dnow",
+
+ /* Transmeta-defined */
+ "recovery", "longrun", NULL, "lrti", NULL, NULL, NULL, NULL,
+ NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+ NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+ NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+
+ /* Other (Linux-defined) */
+ "cxmmx", "k6_mtrr", "cyrix_arr", "centaur_mcr",
+ NULL, NULL, NULL, NULL,
+ "constant_tsc", "up", NULL, NULL, NULL, NULL, NULL, NULL,
+ NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+ NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+
+ /* Intel-defined (#2) */
+ "pni", NULL, NULL, "monitor", "ds_cpl", "vmx", "smx", "est",
+ "tm2", "ssse3", "cid", NULL, NULL, "cx16", "xtpr", NULL,
+ NULL, NULL, "dca", NULL, NULL, NULL, NULL, "popcnt",
+ NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+
+ /* VIA/Cyrix/Centaur-defined */
+ NULL, NULL, "rng", "rng_en", NULL, NULL, "ace", "ace_en",
+ "ace2", "ace2_en", "phe", "phe_en", "pmm", "pmm_en", NULL, NULL,
+ NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+ NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+
+ /* AMD-defined (#2) */
+ "lahf_lm", "cmp_legacy", "svm", "extapic", "cr8legacy", "abm",
+ "sse4a", "misalignsse",
+ "3dnowprefetch", "osvw", "ibs", NULL, NULL, NULL, NULL, NULL,
+ NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+ NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+};
+
+void add_flagname_to_bitmaps(char *flagname, int *features, int *ext_features, int *ext2_features)
+{
+ int i;
+ for ( i = 0 ; i < 32 ; i++ )
+ if (x86_cap_flags[i] && !strcmp (flagname, x86_cap_flags[i])) {
+ *features |= 1 << i;
+ return;
+ }
+ for ( i = 0 ; i < 32 ; i++ )
+ if (x86_cap_flags[32*4+i] && !strcmp (flagname, x86_cap_flags[32*4+i])) {
+ *ext_features |= 1 << i;
+ return;
+ }
+ for ( i = 0 ; i < 32 ; i++ )
+ if (x86_cap_flags[32*1+i] && !strcmp (flagname, x86_cap_flags[32*1+i])) {
+ *ext2_features |= 1 << i;
+ return;
+ }
+ /* Silently ignore Linux-defined features */
+ for ( i = 0 ; i < 32 ; i++ )
+ if (x86_cap_flags[32*3+i] && !strcmp (flagname, x86_cap_flags[32*3+i])) {
+ return;
+ }
+ fprintf(stderr, "CPU feature %s not found\n", flagname);
+}
+
+static void apply_machine_flavor(CPUX86State *env)
+{
+ int plus_features = 0, plus_ext_features = 0, plus_ext2_features = 0;
+ int minus_features = 0, minus_ext_features = 0, minus_ext2_features = 0;
+ int family = -1, model = -1, stepping = -1;
+
+ extern char *machine_flavor;
+ char *s = strdup(machine_flavor);
+ char *featurestr = strtok(s, ",");
+
+ while (featurestr) {
+ char *val;
+ if (featurestr[0] == '+') {
+ add_flagname_to_bitmaps(featurestr + 1, &plus_features, &plus_ext_features, &plus_ext2_features);
+ }
+ else if (featurestr[0] == '-') {
+ add_flagname_to_bitmaps(featurestr + 1, &minus_features, &minus_ext_features, &minus_ext2_features);
+ }
+ else if ((val = strchr(featurestr, '='))) {
+ *val = 0; val++;
+ if (!strcmp(featurestr, "family")) {
+ family = atoi(val);
+ if (family <= 0) {
+ fprintf(stderr, "bad numerical value %s\n", val);
+ exit(1);
+ }
+ env->cpuid_version &= 0xFF;
+ env->cpuid_version |= (family << 8);
+ } else if (!strcmp(featurestr, "model")) {
+ model = atoi(val);
+ if (model <= 0) {
+ fprintf(stderr, "bad numerical value %s\n", val);
+ exit(1);
+ }
+ env->cpuid_version &= 0xFFFFFF0F;
+ env->cpuid_version |= (model << 4);
+ } else if (!strcmp(featurestr, "stepping")) {
+ stepping = atoi(val);
+ if (stepping <= 0) {
+ fprintf(stderr, "bad numerical value %s\n", val);
+ exit(1);
+ }
+ env->cpuid_version &= 0xFFFFFFF0;
+ env->cpuid_version |= stepping;
+ } else {
+ fprintf(stderr, "unknown feature %s\n", featurestr);
+ exit(1);
+ }
+ } else {
+ fprintf(stderr, "feature string `%s' not in format (+feature|-feature|feature=xyz)\n", featurestr);
+ exit(1);
+ }
+ featurestr = strtok(NULL, ",");
+ }
+ free(s);
+ env->cpuid_features |= plus_features;
+ env->cpuid_ext_features |= plus_ext_features;
+ env->cpuid_ext2_features |= plus_ext2_features;
+ env->cpuid_features &= ~minus_features;
+ env->cpuid_ext_features &= ~minus_ext_features;
+ env->cpuid_ext2_features &= ~minus_ext2_features;
+}
+
+static int read_one_cpu_info(CPUX86State *env, FILE *f)
+{
+ char line[300], *val;
+ char vendor_id[13];
+ int family = -1, model = -1, stepping = -1;
+ int features = 0, ext_features = 0, ext2_features = 0;
+
+ while (fgets(line, sizeof(line), f)) {
+ if (!strtok(line, "\t") || line[0]=='\n') {
+ break;
+ }
+ val = strtok(NULL, "\t:");
+ if (!val)
+ val = "";
+ if (*val==' ')
+ val++;
+
+ if (!strcmp(line,"vendor_id")) {
+ strncpy(vendor_id, val, sizeof(vendor_id) - 1);
+ vendor_id[sizeof(vendor_id)-1] = 0;
+ }
+ if (!strcmp(line,"cpu family")) {
+ family = atoi(val);
+ }
+ if (!strcmp(line,"model")) {
+ model = atoi(val);
+ }
+ if (!strcmp(line,"stepping")) {
+ stepping = atoi(val);
+ }
+ if (!strcmp(line,"flags")) {
+ char *flagname;
+ struct flagstorage {
+ char *name;
+ int bit;
+ int *container;
+ };
+
+ flagname = strtok(val, " ");
+ while (flagname) {
+ add_flagname_to_bitmaps(flagname, &features, &ext_features, &ext2_features);
+ flagname = strtok(NULL, " \n");
+ }
+ features &= ~CPUID_ACPI; /* acpi causes guest kernel panic on boot time, in cpu_identify */
+ ext_features &= ~CPUID_EXT_VMX; /* KVM is not recursive */
+ }
+ }
+ if (family==-1 || model==-1 || stepping==-1)
+ return -1;
+ env->cpuid_level = 2;
+ env->cpuid_vendor1 = *(uint32_t *)&vendor_id[0];
+ env->cpuid_vendor2 = *(uint32_t *)&vendor_id[4];
+ env->cpuid_vendor3 = *(uint32_t *)&vendor_id[8];
+ env->cpuid_version = (family << 8) | (model << 4) | stepping;
+ env->cpuid_features = features;
+ env->cpuid_ext_features = ext_features;
+ env->cpuid_ext2_features = ext2_features;
+ env->pat = 0x0007040600070406ULL;
+ /* TODO expose real cpuid extended level */
+#ifdef TARGET_X86_64
+ env->cpuid_xlevel = 0x80000008;
+#else
+ env->cpuid_xlevel = 0;
+#endif
+ return 0;
+}
+
+static int set_guest_cpu_hostlike(CPUX86State *env) {
+ FILE *f;
+ f = fopen("/proc/cpuinfo", "r");
+ if (!f) {
+ fprintf(stderr, "falling back to standard guest cpu\n");
+ return -1;
+ }
+ read_one_cpu_info(env, f);
+ fclose(f);
+ return 0;
+}
+
+static int set_guest_cpu_standard(CPUX86State *env)
+{
+ int family, model, stepping;
+#ifdef TARGET_X86_64
+ env->cpuid_vendor1 = 0x68747541; /* "Auth" */
+ env->cpuid_vendor2 = 0x69746e65; /* "enti" */
+ env->cpuid_vendor3 = 0x444d4163; /* "cAMD" */
+ family = 6;
+ model = 2;
+ stepping = 3;
+#else
+ env->cpuid_vendor1 = 0x756e6547; /* "Genu" */
+ env->cpuid_vendor2 = 0x49656e69; /* "ineI" */
+ env->cpuid_vendor3 = 0x6c65746e; /* "ntel" */
+#if 0
+ /* pentium 75-200 */
+ family = 5;
+ model = 2;
+ stepping = 11;
+#else
+ /* pentium pro */
+ family = 6;
+ model = 3;
+ stepping = 3;
+#endif
+#endif
+ env->cpuid_level = 2;
+ env->cpuid_version = (family << 8) | (model << 4) | stepping;
+ env->cpuid_features = (CPUID_FP87 | CPUID_DE | CPUID_PSE |
+ CPUID_TSC | CPUID_MSR | CPUID_MCE |
+ CPUID_CX8 | CPUID_PGE | CPUID_CMOV |
+ CPUID_PAT);
+ env->pat = 0x0007040600070406ULL;
+ env->cpuid_ext_features = CPUID_EXT_SSE3;
+ env->cpuid_features |= CPUID_FXSR | CPUID_MMX | CPUID_SSE | CPUID_SSE2 | CPUID_PAE | CPUID_SEP;
+ env->cpuid_features |= CPUID_APIC;
+ env->cpuid_xlevel = 0;
+#ifdef TARGET_X86_64
+ /* currently not enabled for std i386 because not fully tested */
+ env->cpuid_ext2_features = (env->cpuid_features & 0x0183F3FF);
+ env->cpuid_ext2_features |= CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX;
+ env->cpuid_xlevel = 0x80000008;
+
+ /* these features are needed for Win64 and aren't fully implemented */
+ env->cpuid_features |= CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA;
+ /* this feature is needed for Solaris and isn't fully implemented */
+ env->cpuid_features |= CPUID_PSE36;
+#endif
+ return 0;
+}
+
CPUX86State *cpu_x86_init(void)
{
CPUX86State *env;
@@ -80,64 +346,23 @@ CPUX86State *cpu_x86_init(void)
}
#endif
{
- int family, model, stepping;
-#ifdef TARGET_X86_64
- env->cpuid_vendor1 = 0x68747541; /* "Auth" */
- env->cpuid_vendor2 = 0x69746e65; /* "enti" */
- env->cpuid_vendor3 = 0x444d4163; /* "cAMD" */
- family = 6;
- model = 2;
- stepping = 3;
-#else
- env->cpuid_vendor1 = 0x756e6547; /* "Genu" */
- env->cpuid_vendor2 = 0x49656e69; /* "ineI" */
- env->cpuid_vendor3 = 0x6c65746e; /* "ntel" */
-#if 0
- /* pentium 75-200 */
- family = 5;
- model = 2;
- stepping = 11;
-#else
- /* pentium pro */
- family = 6;
- model = 3;
- stepping = 3;
-#endif
-#endif
- env->cpuid_level = 2;
- env->cpuid_version = (family << 8) | (model << 4) | stepping;
- env->cpuid_features = (CPUID_FP87 | CPUID_DE | CPUID_PSE |
- CPUID_TSC | CPUID_MSR | CPUID_MCE |
- CPUID_CX8 | CPUID_PGE | CPUID_CMOV |
- CPUID_PAT);
- env->pat = 0x0007040600070406ULL;
- env->cpuid_ext_features = CPUID_EXT_SSE3;
- env->cpuid_features |= CPUID_FXSR | CPUID_MMX | CPUID_SSE | CPUID_SSE2 | CPUID_PAE | CPUID_SEP;
- env->cpuid_features |= CPUID_APIC;
- env->cpuid_xlevel = 0;
- {
- const char *model_id = "QEMU Virtual CPU version " QEMU_VERSION;
- int c, len, i;
- len = strlen(model_id);
- for(i = 0; i < 48; i++) {
- if (i >= len)
- c = '\0';
- else
- c = model_id[i];
- env->cpuid_model[i >> 2] |= c << (8 * (i & 3));
- }
+ extern int use_hostlike_cpu;
+ if (!use_hostlike_cpu || set_guest_cpu_hostlike(env))
+ set_guest_cpu_standard(env);
+ apply_machine_flavor(env);
+ }
+ {
+ const char *model_id = "QEMU Virtual CPU version " QEMU_VERSION;
+ int c, len, i;
+
+ len = strlen(model_id);
+ for(i = 0; i < 48; i++) {
+ if (i >= len)
+ c = '\0';
+ else
+ c = model_id[i];
+ env->cpuid_model[i >> 2] |= c << (8 * (i & 3));
}
-#ifdef TARGET_X86_64
- /* currently not enabled for std i386 because not fully tested */
- env->cpuid_ext2_features = (env->cpuid_features & 0x0183F3FF);
- env->cpuid_ext2_features |= CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX;
- env->cpuid_xlevel = 0x80000008;
-
- /* these features are needed for Win64 and aren't fully implemented */
- env->cpuid_features |= CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA;
- /* this feature is needed for Solaris and isn't fully implemented */
- env->cpuid_features |= CPUID_PSE36;
-#endif
}
cpu_reset(env);
#ifdef USE_KQEMU

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