From 9abef2383d1b454a588587028568bb547b7a0842 Mon Sep 17 00:00:00 2001 From: neel Date: Sat, 20 Dec 2014 19:47:51 +0000 Subject: Emulate writes to the IA32_MISC_ENABLE MSR. PR: 196093 Reported by: db Tested by: db Discussed with: grehan MFC after: 1 week --- sys/amd64/vmm/intel/vmx_msr.c | 26 ++++++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-) (limited to 'sys/amd64/vmm/intel') diff --git a/sys/amd64/vmm/intel/vmx_msr.c b/sys/amd64/vmm/intel/vmx_msr.c index 746ca73..f6bbf2a 100644 --- a/sys/amd64/vmm/intel/vmx_msr.c +++ b/sys/amd64/vmm/intel/vmx_msr.c @@ -376,9 +376,31 @@ vmx_rdmsr(struct vmx *vmx, int vcpuid, u_int num, uint64_t *val, bool *retu) int 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) { + 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: error = EINVAL; break; -- cgit v1.1