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Emulate writes to the IA32_MISC_ENABLE MSR.

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PR:		196093
Reported by:	db
Tested by:	db
Discussed with:	grehan
MFC after:	1 week
This commit is contained in:
neel 2014-12-20 19:47:51 +00:00
parent 8f1c7a6d1b
commit 9abef2383d
1 changed files with 24 additions and 2 deletions
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26
sys/amd64/vmm/intel/vmx_msr.c
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@ -376,9 +376,31 @@ vmx_rdmsr(struct vmx *vmx, int vcpuid, u_int num, uint64_t *val, bool *retu)
int int
vmx_wrmsr(struct vmx *vmx, int vcpuid, u_int num, uint64_t val, bool *retu) vmx_wrmsr(struct vmx *vmx, int vcpuid, u_int num, uint64_t val, bool *retu)
{ {
int error = 0; uint64_t changed;
int error;
error = 0;
switch (num) { switch (num) {
case MSR_IA32_MISC_ENABLE:
changed = val ^ misc_enable;
/*
* If the host has disabled the NX feature then the guest
* also cannot use it. However, a Linux guest will try to
* enable the NX feature by writing to the MISC_ENABLE MSR.
*
* This can be safely ignored because the memory management
* code looks at CPUID.80000001H:EDX.NX to check if the
* functionality is actually enabled.
*/
changed &= ~(1UL << 34);
/*
* Punt to userspace if any other bits are being modified.
*/
if (changed)
error = EINVAL;
break;
default: default:
error = EINVAL; error = EINVAL;
break; break;