On Tue, Oct 27, 2026 at 3:12 PM Sean Christopherson <[email protected]> wrote: > > WARN and reject user accesses to guest memory if the associated VM is dying > even if the current address space happens to be the correct address space. > Accessing guest memory after the last reference to the VM has been put may > be "fine" from a safety perspective, but it's still a KVM bug. > > Signed-off-by: Sean Christopherson <[email protected]>
Reviewed-by: James Houghton <[email protected]> > --- > include/linux/kvm_host.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index f3f59bdf7e18..ba8ea62b7304 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -1355,7 +1355,8 @@ int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct > gfn_to_hva_cache *ghc, > > static __always_inline __must_check bool kvm_can_do_uaccess(struct kvm *kvm) > { > - return !WARN_ON_ONCE(current->mm != kvm->mm); > + return !WARN_ON_ONCE(current->mm != kvm->mm || > + !refcount_read(&kvm->users_count)); > } > > #define BUILD_KVM_COPY_USER_WRAPPER(fn, to_user, from_user) > \ > -- > 2.56.0.307.g5fe7bd680c-goog >
