On Wed, Apr 28, 2010 at 04:47:14PM +0300, Avi Kivity wrote: > Currently we run with EFER.NX=1 on the guest even if the guest value is 0. > This is fine with shadow, since we check bit 63 when instantiating a page > table, and fault if bit 63 is set while EFER.NX is clear. > > This doesn't work with EPT, since we no longer get the change to check guest > ptes. So we need to run with EFER.NX=0. > > This is complicated by the fact that if we switch EFER.NX on the host, we'll > trap immediately, since some host pages are mapped with the NX bit set. As > a result, we need to switch the MSR atomically during guest entry and exit. > > This patchset implements the complications described above. > > Avi Kivity (5): > KVM: Let vcpu structure alignment be determined at runtime > KVM: VMX: Add definition for msr autoload entry > KVM: VMX: Add definitions for guest and host EFER autoswitch vmcs > entries > KVM: VMX: Add facility to atomically switch MSRs on guest entry/exit > KVM: VMX: Atomically switch efer if EPT && !EFER.NX Applied, thanks. Out of curiosity, did you measure the vmentry/vmexit overhead? -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
