On Fri, Mar 20, 2020 at 11:26:41AM +0100, Laurent Dufour wrote: > This series is fixing a SVM hang occurring when starting a SVM requiring > more secure memory than available. The hang happens in the SVM when calling > UV_ESM. > > The following is happening: > > 1. SVM calls UV_ESM > 2. Ultravisor (UV) calls H_SVM_INIT_START > 3. Hypervisor (HV) calls UV_REGISTER_MEM_SLOT > 4. UV returns error because there is not enough free secure memory > 5. HV enter the error path in kvmppc_h_svm_init_start() > 6. In the return path, since kvm->arch.secure_guest is not yet set hrfid is > called > 7. As the HV doesn't know the SVM calling context hrfid is jumping to > unknown address in the SVM leading to various expections. > > This series fixes the setting of kvm->arch.secure_guest in > kvmppc_h_svm_init_start() to ensure that UV_RETURN is called on the return > path to get back to the UV. > > In addition to ensure that a malicious VM will not call UV reserved Hcall, > a check of the Secure bit in the calling MSR is addded to reject such a > call. > > It is assumed that the UV will filtered out such Hcalls made by a malicious > SVM. > > Laurent Dufour (2): > KVM: PPC: Book3S HV: check caller of H_SVM_* Hcalls > KVM: PPC: Book3S HV: H_SVM_INIT_START must call UV_RETURN > > arch/powerpc/kvm/book3s_hv.c | 32 ++++++++++++++++++++---------- > arch/powerpc/kvm/book3s_hv_uvmem.c | 3 ++- > 2 files changed, 23 insertions(+), 12 deletions(-) Thanks, series applied to my kvm-ppc-next branch. Paul.
