On Wed, 17 Oct 2018 at 06:57, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > With live migration support and finally a good solution for CR2/DR6 > exception payloads, nested VMX should finally be ready for having a stable > userspace ABI. The results of syzkaller fuzzing are not perfect but not > horrible either (and might be partially due to running on GCE, so that > effectively we're testing three-level nesting on a fork of upstream KVM!). > Enabling it by default seems like a nice way to conclude the 4.20 > pull request. :) > > Unfortunately, enabling nested SVM in 2009 was a bit premature. However, > until live migration support is in place we can reasonably expect that > it does not offer much in terms of ABI guarantees. Therefore we are > still in time to break things and conform as much as possible to the > interface used for VMX. > > Suggested-by: Jim Mattson <jmattson@xxxxxxxxxx> > Suggested-by: Liran Alon <liran.alon@xxxxxxxxxx> > Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> > --- > arch/x86/kvm/vmx.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index e665aa7167cf..89fc2a744d7f 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -107,7 +107,7 @@ module_param_named(enable_shadow_vmcs, enable_shadow_vmcs, bool, S_IRUGO); > * VMX and be a hypervisor for its own guests. If nested=0, guests may not > * use VMX instructions. > */ > -static bool __read_mostly nested = 0; > +static bool __read_mostly nested = 1; Really cool, a milestone for nested. :) Regards, Wanpeng Li
