svn commit: r255288 - head/sys/amd64/vmm

[Peter Grehan]

Author: grehan
Date: Fri Sep  6 05:20:11 2013
New Revision: 255288
URL: http://svnweb.freebsd.org/changeset/base/255288

Log:
  Emulate reading of the IA32_MISC_ENABLE MSR, by returning
  the host MSR and masking off features that aren't supported.
  Linux reads this MSR to detect if NX has been disabled via
  BIOS.

Modified:
  head/sys/amd64/vmm/vmm_msr.c

Modified: head/sys/amd64/vmm/vmm_msr.c
==============================================================================
--- head/sys/amd64/vmm/vmm_msr.c        Fri Sep  6 05:16:10 2013        
(r255287)
+++ head/sys/amd64/vmm/vmm_msr.c        Fri Sep  6 05:20:11 2013        
(r255288)
@@ -57,6 +57,7 @@ static struct vmm_msr vmm_msr[] = {
        { MSR_PAT,      VMM_MSR_F_EMULATE | VMM_MSR_F_INVALID },
        { MSR_BIOS_SIGN,VMM_MSR_F_EMULATE },
        { MSR_MCG_CAP,  VMM_MSR_F_EMULATE | VMM_MSR_F_READONLY },
+       { MSR_IA32_MISC_ENABLE, VMM_MSR_F_EMULATE | VMM_MSR_F_READONLY },
 };
 
 #define        vmm_msr_num     (sizeof(vmm_msr) / sizeof(vmm_msr[0]))
@@ -91,7 +92,7 @@ void
 guest_msrs_init(struct vm *vm, int cpu)
 {
        int i;
-       uint64_t *guest_msrs;
+       uint64_t *guest_msrs, misc;
 
        guest_msrs = vm_guest_msrs(vm, cpu);
        
@@ -115,6 +116,20 @@ guest_msrs_init(struct vm *vm, int cpu)
                                PAT_VALUE(6, PAT_UNCACHED)        |
                                PAT_VALUE(7, PAT_UNCACHEABLE);
                        break;
+               case MSR_IA32_MISC_ENABLE:
+                       misc = rdmsr(MSR_IA32_MISC_ENABLE);
+                       /*
+                        * Set mandatory bits
+                        *  11:   branch trace disabled
+                        *  12:   PEBS unavailable
+                        * Clear unsupported features
+                        *  16:   SpeedStep enable
+                        *  18:   enable MONITOR FSM
+                         */
+                       misc |= (1 << 12) | (1 << 11);
+                       misc &= ~((1 << 18) | (1 << 16));
+                       guest_msrs[i] = misc;
+                        break;
                default:
                        panic("guest_msrs_init: missing initialization for msr "
                              "0x%0x", vmm_msr[i].num);
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