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Emulate reading of the IA32_MISC_ENABLE MSR, by returning

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the host MSR and masking off features that aren't supported.
Linux reads this MSR to detect if NX has been disabled via
BIOS.
This commit is contained in:
Peter Grehan 2013-09-06 05:20:11 +00:00
parent 8b7e3e3022
commit 76c35ba80f
1 changed files with 16 additions and 1 deletions
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17
sys/amd64/vmm/vmm_msr.c
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@ -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);