Re: [Qemu-devel] [PATCH v4 6/8] Pass cpu speed into SM BIOS.

[Gleb Natapov <gleb@qumranet.com>]

Sorry, use this one instead.

---
    Signed-off-by: Gleb Natapov <gleb@qumranet.com>

diff --git a/hw/pc.c b/hw/pc.c
index 933e936..aae9fc6 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -49,6 +49,8 @@
 
 #define MAX_IDE_BUS 2
 
+#define FW_CFG_PC_CPUSPEED (FW_CFG_ARCH_LOCAL + 0x00)
+
 static fdctrl_t *floppy_controller;
 static RTCState *rtc_state;
 static PITState *pit;
@@ -369,6 +371,89 @@ static uint32_t ioport92_read(void *opaque, uint32_t addr)
     return ioport_get_a20() << 1;
 }
 
+#ifdef __linux__
+/* get_freq () function is taken from conky source code */
+#define CPUFREQ_PREFIX "/sys/devices/system/cpu"
+#define CPUFREQ_POSTFIX "cpufreq/scaling_cur_freq"
+
+/* return system frequency in MHz (use divisor=1) or GHz (use divisor=1000) */
+static double get_freq(int divisor, unsigned int cpu)
+{
+	FILE *f;
+	char frequency[32];
+	char s[256];
+	double freq = 0;
+
+	if (divisor <= 0)
+		return 0;
+
+	snprintf(s, 256, "%s/cpu%d/%s", CPUFREQ_PREFIX, cpu - 1, CPUFREQ_POSTFIX);
+	f = fopen(s, "r");
+	if (f) {
+		/* if there's a cpufreq /sys node, read the current frequency from
+		 * this node and divide by 1000 to get Mhz. */
+		if (fgets(s, sizeof(s), f)) {
+			s[strlen(s) - 1] = '\0';
+			freq = strtod(s, NULL);
+		}
+		fclose(f);
+		return (freq / 1000) / divisor;
+	}
+
+	// open the CPU information file
+	f = fopen("/proc/cpuinfo", "r");
+	if (!f) {
+		perror("Failed to access '/proc/cpuinfo' at get_freq()");
+		return 0;
+	}
+
+	// read the file
+	while (fgets(s, sizeof(s), f) != NULL) {
+
+#if defined(__i386) || defined(__x86_64)
+		// and search for the cpu mhz
+		if (strncmp(s, "cpu MHz", 7) == 0 && cpu == 0) {
+#else
+#if defined(__alpha)
+		// different on alpha
+		if (strncmp(s, "cycle frequency [Hz]", 20) == 0 && cpu == 0) {
+#else
+		// this is different on ppc for some reason
+		if (strncmp(s, "clock", 5) == 0 && cpu == 0) {
+#endif // defined(__alpha)
+#endif // defined(__i386) || defined(__x86_64)
+
+			// copy just the number
+			strcpy(frequency, strchr(s, ':') + 2);
+#if defined(__alpha)
+			// strip " est.\n"
+			frequency[strlen(frequency) - 6] = '\0';
+			// kernel reports in Hz
+			freq = strtod(frequency, NULL) / 1000000;
+#else
+			// strip \n
+			frequency[strlen(frequency) - 1] = '\0';
+			freq = strtod(frequency, NULL);
+#endif
+			break;
+		}
+		if (strncmp(s, "processor", 9) == 0) {
+			cpu--;
+			continue;
+		}
+	}
+
+	fclose(f);
+	return freq / divisor;
+}
+#else
+static double get_freq(int divisor, unsigned int cpu)
+{
+    return 0;
+}
+#endif
+
+
 /***********************************************************/
 /* Bochs BIOS debug ports */
 
@@ -418,6 +503,7 @@ static void bochs_bios_write(void *opaque, uint32_t addr, uint32_t val)
 
 static void bochs_bios_init(void)
 {
+    uint16_t cpu_speed;
     void *fw_cfg;
 
     register_ioport_write(0x400, 1, 2, bochs_bios_write, NULL);
@@ -433,6 +519,8 @@ static void bochs_bios_init(void)
 
     fw_cfg = fw_cfg_init(BIOS_CFG_IOPORT, 0);
     fw_cfg_add_i32(fw_cfg, FW_CFG_ID, 1);
+    cpu_speed = (uint16_t)get_freq(1, 1);
+    fw_cfg_add_i16(fw_cfg, FW_CFG_PC_CPUSPEED, cpu_speed);
 }
 
 /* Generate an initial boot sector which sets state and jump to
--
			Gleb.