From: David Hildenbrand Date: Thu, 24 Aug 2017 18:51:36 +0000 (+0200) Subject: KVM: x86: allow setting identity map addr with no vcpus only X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=1af1ac910bb3394ac1c0062f5781983dde40a8c0;p=openwrt%2Fstaging%2Fblogic.git KVM: x86: allow setting identity map addr with no vcpus only Changing it afterwards doesn't make too much sense and will only result in inconsistencies. Reviewed-by: Radim Krčmář Signed-off-by: David Hildenbrand Signed-off-by: Radim Krčmář --- diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 22bc5a052a5d..dd2dd96927b8 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -1131,6 +1131,7 @@ This ioctl is required on Intel-based hosts. This is needed on Intel hardware because of a quirk in the virtualization implementation (see the internals documentation when it pops into existence). +Fails if any VCPU has already been created. 4.41 KVM_SET_BOOT_CPU_ID diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 632561b2a3f6..b0d291518e88 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4034,10 +4034,16 @@ long kvm_arch_vm_ioctl(struct file *filp, case KVM_SET_IDENTITY_MAP_ADDR: { u64 ident_addr; + mutex_lock(&kvm->lock); + r = -EINVAL; + if (kvm->created_vcpus) + goto set_identity_unlock; r = -EFAULT; if (copy_from_user(&ident_addr, argp, sizeof ident_addr)) - goto out; + goto set_identity_unlock; r = kvm_vm_ioctl_set_identity_map_addr(kvm, ident_addr); +set_identity_unlock: + mutex_unlock(&kvm->lock); break; } case KVM_SET_NR_MMU_PAGES: