From: Bruce Rogers Date: Fri, 15 Feb 2019 15:12:04 -0700 Subject: Revert "target/i386: kvm: add VMX migration blocker" This reverts commit d98f26073bebddcd3da0ba1b86c3a34e840c0fb8. Here is some text explaining the revert: I've thought about this some more, and with upstream discussions about it having stagnated, at this point I think the best solution is to revert the patch which considers it a migration blocker to have the vmx feature enabled. It's worth noting that not only are migrations blocked, but saving of the vm state via save/restore and snapshots. Given that it is still widely known that Nested Virtualization is not supported by SUSE and other vendors, but is still used by quite a few people who understand that there are caveats with it's usage, I believe this migration blocker is more hurtful than helpful. The fact that as of the v4.20 kernel, nested virtualization is enabled by default (for vmx), was partly why the patch was added in the first place. But my perspective is that perhaps enabling nested was still a bit premature. I will make sure our qemu changelog explains that despite removing that migration blocker, the user is warned that nested virtualization is still a "use at your own risk feature". [BR: BSC#1121604] Signed-off-by: Bruce Rogers --- target/i386/kvm.c | 12 ------------ 1 file changed, 12 deletions(-) diff --git a/target/i386/kvm.c b/target/i386/kvm.c index b2401d13ea..f97bfc164d 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -855,7 +855,6 @@ static int hyperv_init_vcpu(X86CPU *cpu) } static Error *invtsc_mig_blocker; -static Error *vmx_mig_blocker; #define KVM_MAX_CPUID_ENTRIES 100 @@ -1248,17 +1247,6 @@ int kvm_arch_init_vcpu(CPUState *cs) !!(c->ecx & CPUID_EXT_SMX); } - if ((env->features[FEAT_1_ECX] & CPUID_EXT_VMX) && !vmx_mig_blocker) { - error_setg(&vmx_mig_blocker, - "Nested VMX virtualization does not support live migration yet"); - r = migrate_add_blocker(vmx_mig_blocker, &local_err); - if (local_err) { - error_report_err(local_err); - error_free(vmx_mig_blocker); - return r; - } - } - if (env->mcg_cap & MCG_LMCE_P) { has_msr_mcg_ext_ctl = has_msr_feature_control = true; }