From: Ian Jackson <ian.jackson@eu.citrix.com>
Date: Wed, 24 Mar 2010 17:15:12 +0000 (+0000)
Subject: Add sanity check for vcpu config
X-Git-Tag: xen-4.0.0-rc8~1
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=24e4c759d63bda8b8cb6ebfd431891525e9923b8;p=qemu-xen-4.4-testing.git

Add sanity check for vcpu config

Currently Xen/Qemu support max 128 vcpus. To avoid mis-setting
at config file, this patch add sanity check for vcpu config.
1. maxvcpus and vcpus should no more than HVM_MAX_VCPUS (128)
2. vcpus should no more than maxvcpus.

Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>
---

diff --git a/vl.c b/vl.c
index 16de1026a..9f95c2f3e 100644
--- a/vl.c
+++ b/vl.c
@@ -4706,6 +4706,34 @@ static void termsig_setup(void)
 
 #endif
 
+/* 32bit Hamming weight */
+unsigned int hweight32(unsigned int w)
+{
+	unsigned int res = w - ((w >> 1) & 0x55555555);
+	res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
+	res = (res + (res >> 4)) & 0x0F0F0F0F;
+	res = res + (res >> 8);
+	return (res + (res >> 16)) & 0x000000FF;
+}
+
+static void vcpu_sanity_check(void)
+{
+    int i, vcpu_avail_weight = 0;
+
+    for (i=0; i<((HVM_MAX_VCPUS + 31)/32); i++)
+        vcpu_avail_weight += hweight32(vcpu_avail[i]);
+
+    if (vcpus > HVM_MAX_VCPUS) {
+        fprintf(stderr, "maxvcpus and vcpus should not more than %d\n",
+                         HVM_MAX_VCPUS);
+        exit(EXIT_FAILURE);
+    }
+    if (vcpu_avail_weight > vcpus) {
+        fprintf(stderr, "vcpus should not more than maxvcpus\n");
+        exit(EXIT_FAILURE);
+    }
+}
+
 #define STEP   8   /* 8 characters fill uint32_t bitmap */
 #define SPACE  8   /* space for non-hex characters in vcpu str */
 #define MAX_VCPU_STR_LEN    ((HVM_MAX_VCPUS + 3)/4 + SPACE)
@@ -5569,6 +5597,8 @@ int main(int argc, char **argv, char **envp)
         exit(1);
     }
 
+    vcpu_sanity_check();
+
     if (nographic) {
        if (serial_device_index == 0)
            serial_devices[0] = "stdio";