xl: implement parsing of cpuid parameter and translate to Xen interface

Parses a string enumerating cpuid flags and their behavior.
The syntax is: cpuid = "host,<flagname>=[01xks],..."
Supports:
0: clear this flag
1: set this flag
x: don't care, use the default handling
k: use the host value
s: as k, but keep stable across migrations

For multiple bit flags there have to be numbers passed (hex or dec),
like: family=0x10,model=4

Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
committer: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

3 files changed, 231 insertions, 0 deletions

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 4e1fd04284..b61f8599c3 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -3524,6 +3524,225 @@ uint32_t libxl_vm_get_start_time(libxl_ctx *ctx, uint32_t domid)
     return ret;
 }
 
+#define CPUID_REG_INV 0
+#define CPUID_REG_EAX 1
+#define CPUID_REG_EBX 2
+#define CPUID_REG_ECX 3
+#define CPUID_REG_EDX 4
+
+/* mapping CPUID features to names
+ * holds a "name" for each feature, specified by the "leaf" number (and an
+ * optional "subleaf" in ECX), the "reg"ister (EAX-EDX) used and a number of
+ * bits starting with "bit" and being "length" bits long.
+ * Used for the static structure describing all features.
+ */
+struct cpuid_flags {
+    char* name;
+    uint32_t leaf;
+    uint32_t subleaf;
+    int reg;
+    int bit;
+    int length;
+};
+
+/* go through the dynamic array finding the entry for a specified leaf.
+ * if no entry exists, allocate one and return that.
+ */
+static libxl_cpuid_policy_list cpuid_find_match(libxl_cpuid_policy_list *list,
+                                          uint32_t leaf, uint32_t subleaf)
+{
+    int i = 0;
+
+    if (*list != NULL) {
+        for (i = 0; (*list)[i].input[0] != XEN_CPUID_INPUT_UNUSED; i++) {
+            if ((*list)[i].input[0] == leaf && (*list)[i].input[1] == subleaf)
+                return *list + i;
+        }
+    }
+    *list = realloc(*list, sizeof((*list)[0]) * (i + 2));
+    (*list)[i].input[0] = leaf;
+    (*list)[i].input[1] = subleaf;
+    memset((*list)[i].policy, 0, 4 * sizeof(char*));
+    (*list)[i + 1].input[0] = XEN_CPUID_INPUT_UNUSED;
+    return *list + i;
+}
+
+/* parse a single key=value pair and translate it into the libxc
+ * used interface using 32-characters strings for each register.
+ * Will overwrite earlier entries and thus can be called multiple
+ * times.
+ */
+int libxl_cpuid_parse_config(libxl_cpuid_policy_list *cpuid, const char* str)
+{
+#define NA XEN_CPUID_INPUT_UNUSED
+    struct cpuid_flags cpuid_flags[] = {
+        {"maxleaf",      0x00000000, NA, CPUID_REG_EAX,  0, 32},
+      /* the following two entries are subject to tweaking later in the code */
+        {"family",       0x00000001, NA, CPUID_REG_EAX,  8,  8},
+        {"model",        0x00000001, NA, CPUID_REG_EAX,  4,  8},
+        {"stepping",     0x00000001, NA, CPUID_REG_EAX,  0,  4},
+        {"localapicid",  0x00000001, NA, CPUID_REG_EBX, 24,  8},
+        {"proccount",    0x00000001, NA, CPUID_REG_EBX, 16,  8},
+        {"clflush",      0x00000001, NA, CPUID_REG_EBX,  8,  8},
+        {"brandid",      0x00000001, NA, CPUID_REG_EBX,  0,  8},
+        {"f16c",         0x00000001, NA, CPUID_REG_ECX, 29,  1},
+        {"avx",          0x00000001, NA, CPUID_REG_ECX, 28,  1},
+        {"osxsave",      0x00000001, NA, CPUID_REG_ECX, 27,  1},
+        {"xsave",        0x00000001, NA, CPUID_REG_ECX, 26,  1},
+        {"aes",          0x00000001, NA, CPUID_REG_ECX, 25,  1},
+        {"popcnt",       0x00000001, NA, CPUID_REG_ECX, 23,  1},
+        {"movbe",        0x00000001, NA, CPUID_REG_ECX, 22,  1},
+        {"x2apic",       0x00000001, NA, CPUID_REG_ECX, 21,  1},
+        {"sse4.2",       0x00000001, NA, CPUID_REG_ECX, 20,  1},
+        {"sse4.1",       0x00000001, NA, CPUID_REG_ECX, 19,  1},
+        {"dca",          0x00000001, NA, CPUID_REG_ECX, 18,  1},
+        {"pdcm",         0x00000001, NA, CPUID_REG_ECX, 15,  1},
+        {"xtpr",         0x00000001, NA, CPUID_REG_ECX, 14,  1},
+        {"cmpxchg16",    0x00000001, NA, CPUID_REG_ECX, 13,  1},
+        {"cntxid",       0x00000001, NA, CPUID_REG_ECX, 10,  1},
+        {"ssse3",        0x00000001, NA, CPUID_REG_ECX,  9,  1},
+        {"tm2",          0x00000001, NA, CPUID_REG_ECX,  8,  1},
+        {"est",          0x00000001, NA, CPUID_REG_ECX,  7,  1},
+        {"smx",          0x00000001, NA, CPUID_REG_ECX,  6,  1},
+        {"vmx",          0x00000001, NA, CPUID_REG_ECX,  5,  1},
+        {"dscpl",        0x00000001, NA, CPUID_REG_ECX,  4,  1},
+        {"monitor",      0x00000001, NA, CPUID_REG_ECX,  3,  1},
+        {"dtes64",       0x00000001, NA, CPUID_REG_ECX,  2,  1},
+        {"sse3",         0x00000001, NA, CPUID_REG_ECX,  0,  1},
+        {"pbe",          0x00000001, NA, CPUID_REG_EDX, 31,  1},
+        {"ia64",         0x00000001, NA, CPUID_REG_EDX, 30,  1},
+        {"tm",           0x00000001, NA, CPUID_REG_EDX, 29,  1},
+        {"htt",          0x00000001, NA, CPUID_REG_EDX, 28,  1},
+        {"ss",           0x00000001, NA, CPUID_REG_EDX, 27,  1},
+        {"sse2",         0x00000001, NA, CPUID_REG_EDX, 26,  1},
+        {"sse",          0x00000001, NA, CPUID_REG_EDX, 25,  1},
+        {"fxsr",         0x00000001, NA, CPUID_REG_EDX, 24,  1},
+        {"mmx",          0x00000001, NA, CPUID_REG_EDX, 23,  1},
+        {"acpi",         0x00000001, NA, CPUID_REG_EDX, 22,  1},
+        {"ds",           0x00000001, NA, CPUID_REG_EDX, 21,  1},
+        {"clfsh",        0x00000001, NA, CPUID_REG_EDX, 19,  1},
+        {"psn",          0x00000001, NA, CPUID_REG_EDX, 18,  1},
+        {"pse36",        0x00000001, NA, CPUID_REG_EDX, 17,  1},
+        {"pat",          0x00000001, NA, CPUID_REG_EDX, 16,  1},
+        {"cmov",         0x00000001, NA, CPUID_REG_EDX, 15,  1},
+        {"mca",          0x00000001, NA, CPUID_REG_EDX, 14,  1},
+        {"pge",          0x00000001, NA, CPUID_REG_EDX, 13,  1},
+        {"mtrr",         0x00000001, NA, CPUID_REG_EDX, 12,  1},
+        {"sysenter",     0x00000001, NA, CPUID_REG_EDX, 11,  1},
+        {"apic",         0x00000001, NA, CPUID_REG_EDX,  9,  1},
+        {"cmpxchg8",     0x00000001, NA, CPUID_REG_EDX,  8,  1},
+        {"mce",          0x00000001, NA, CPUID_REG_EDX,  7,  1},
+        {"pae",          0x00000001, NA, CPUID_REG_EDX,  6,  1},
+        {"msr",          0x00000001, NA, CPUID_REG_EDX,  5,  1},
+        {"tsc",          0x00000001, NA, CPUID_REG_EDX,  4,  1},
+        {"pse",          0x00000001, NA, CPUID_REG_EDX,  3,  1},
+        {"de",           0x00000001, NA, CPUID_REG_EDX,  2,  1},
+        {"vme",          0x00000001, NA, CPUID_REG_EDX,  1,  1},
+        {"fpu",          0x00000001, NA, CPUID_REG_EDX,  0,  1},
+        {"topoext",      0x80000001, NA, CPUID_REG_ECX, 22,  1},
+        {"tbm",          0x80000001, NA, CPUID_REG_ECX, 21,  1},
+        {"nodeid",       0x80000001, NA, CPUID_REG_ECX, 19,  1},
+        {"fma4",         0x80000001, NA, CPUID_REG_ECX, 16,  1},
+        {"lwp",          0x80000001, NA, CPUID_REG_ECX, 15,  1},
+        {"wdt",          0x80000001, NA, CPUID_REG_ECX, 13,  1},
+        {"skinit",       0x80000001, NA, CPUID_REG_ECX, 12,  1},
+        {"xop",          0x80000001, NA, CPUID_REG_ECX, 11,  1},
+        {"ibs",          0x80000001, NA, CPUID_REG_ECX, 10,  1},
+        {"osvw",         0x80000001, NA, CPUID_REG_ECX, 10,  1},
+        {"3dnowprefetch",0x80000001, NA, CPUID_REG_ECX,  8,  1},
+        {"misalignsse",  0x80000001, NA, CPUID_REG_ECX,  7,  1},
+        {"sse4a",        0x80000001, NA, CPUID_REG_ECX,  6,  1},
+        {"abm",          0x80000001, NA, CPUID_REG_ECX,  5,  1},
+        {"altmovcr8",    0x80000001, NA, CPUID_REG_ECX,  4,  1},
+        {"extapic",      0x80000001, NA, CPUID_REG_ECX,  3,  1},
+        {"svm",          0x80000001, NA, CPUID_REG_ECX,  2,  1},
+        {"cmplegacy",    0x80000001, NA, CPUID_REG_ECX,  1,  1},
+        {"lahfsahf",     0x80000001, NA, CPUID_REG_ECX,  0,  1},
+        {"3dnow",        0x80000001, NA, CPUID_REG_EDX, 31,  1},
+        {"3dnowext",     0x80000001, NA, CPUID_REG_EDX, 30,  1},
+        {"lm",           0x80000001, NA, CPUID_REG_EDX, 29,  1},
+        {"rdtscp",       0x80000001, NA, CPUID_REG_EDX, 27,  1},
+        {"page1gb",      0x80000001, NA, CPUID_REG_EDX, 26,  1},
+        {"ffxsr",        0x80000001, NA, CPUID_REG_EDX, 25,  1},
+        {"mmxext",       0x80000001, NA, CPUID_REG_EDX, 22,  1},
+        {"nx",           0x80000001, NA, CPUID_REG_EDX, 20,  1},
+        {"syscall",      0x80000001, NA, CPUID_REG_EDX, 11,  1},
+        {"procpkg",      0x00000004,  0, CPUID_REG_EAX, 26,  6},
+        {"apicidsize",   0x80000008, NA, CPUID_REG_ECX, 12,  4},
+        {"nc",           0x80000008, NA, CPUID_REG_ECX,  0,  8},
+
+        {NULL, 0, CPUID_REG_INV, 0, 0}
+    };
+#undef NA
+    char *sep, *val, *endptr;
+    int i;
+    struct cpuid_flags *flag;
+    struct libxl__cpuid_policy *entry;
+    unsigned long num;
+    char flags[33], *resstr;
+
+    sep = strchr(str, '=');
+    if (sep == NULL) {
+        return 1;
+    } else {
+        val = sep + 1;
+    }
+    for (flag = cpuid_flags; flag->name != NULL; flag++) {
+        if(!strncmp(str, flag->name, sep - str) && flag->name[sep - str] == 0)
+            break;
+    }
+    if (flag->name == NULL) {
+        return 2;
+    }
+    entry = cpuid_find_match(cpuid, flag->leaf, flag->subleaf);
+    resstr = entry->policy[flag->reg - 1];
+    if (resstr == NULL) {
+        resstr = strdup("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");
+    }
+    num = strtoull(val, &endptr, 0);
+    flags[flag->length] = 0;
+    if (endptr != val) {
+        /* is this was a valid number, write the binary form into the string */
+        for (i = 0; i < flag->length; i++) {
+            flags[flag->length - 1 - i] = "01"[!!(num & (1 << i))];
+        }
+    } else {
+        switch(val[0]) {
+        case 'x': case 'k': case 's':
+            memset(flags, val[0], flag->length);
+            break;
+        default:
+            return 3;
+        }
+    }
+    /* the family and model entry is potentially split up across
+     * two fields in Fn0000_0001_EAX, so handle them here separately.
+     */
+    if (!strncmp(str, "family", sep - str)) {
+        if (num < 16) {
+            memcpy(resstr + (32 - 4) - flag->bit, flags + 4, 4);
+            memcpy(resstr + (32 - 8) - 20, "00000000", 8);
+        } else {
+            num -= 15;
+            memcpy(resstr + (32 - 4) - flag->bit, "1111", 4);
+            for (i = 0; i < 7; i++) {
+                flags[7 - i] = "01"[num & 1];
+                num >>= 1;
+            }
+            memcpy(resstr + (32 - 8) - 20, flags, 8);
+        }
+    } else if (!strncmp(str, "model", sep - str)) {
+        memcpy(resstr + (32 - 4) - 16, flags, 4);
+        memcpy(resstr + (32 - 4) - flag->bit, flags + 4, 4);
+    } else {
+        memcpy(resstr + (32 - flag->length) - flag->bit, flags,
+               flag->length);
+    }
+    entry->policy[flag->reg - 1] = resstr;
+
+    return 0;
+}
+
 char *libxl_tmem_list(libxl_ctx *ctx, uint32_t domid, int use_long)
 {
     int rc;
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index c1c40b1381..a1e0fa400c 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -411,6 +411,7 @@ int libxl_device_pci_shutdown(libxl_ctx *ctx, uint32_t domid);
 int libxl_device_pci_list_assigned(libxl_ctx *ctx, libxl_device_pci **list, uint32_t domid, int *num);
 int libxl_device_pci_list_assignable(libxl_ctx *ctx, libxl_device_pci **list, int *num);
 int libxl_device_pci_parse_bdf(libxl_ctx *ctx, libxl_device_pci *pcidev, const char *str);
+int libxl_cpuid_parse_config(libxl_cpuid_policy_list *cpuid, const char* str);
 
 /*
  * Functions for allowing users of libxl to store private data
diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 9aa4b78b2d..2b863dea8d 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -1085,6 +1085,17 @@ skip_vfb:
         }
     }
 
+    if (!xlu_cfg_get_string(config, "cpuid", &buf)) {
+        char *buf2, *p, *strtok_ptr;
+
+        buf2 = strdup(buf);
+        p = strtok_r(buf2, ",", &strtok_ptr);
+        for (p = strtok_r(NULL, ",", &strtok_ptr); p != NULL;
+             p = strtok_r(NULL, ",", &strtok_ptr))
+            libxl_cpuid_parse_config(&b_info->cpuid, p);
+        free(buf2);
+    }
+
     if (c_info->hvm == 1) {
         /* init dm from c and b */
         init_dm_info(dm_info, c_info, b_info);