Messages in this thread | | | From | Vitaly Kuznetsov <> | Subject | [PATCH 0/6] KVM: nSVM: Fix issues when SMM is entered from L2 | Date | Mon, 28 Jun 2021 12:44:19 +0200 |
| |
This is a continuation of "[PATCH RFC] KVM: nSVM: Fix L1 state corruption upon return from SMM".
VMCB split commit 4995a3685f1b ("KVM: SVM: Use a separate vmcb for the nested L2 guest") broke return from SMM when we entered there from guest (L2) mode. Gen2 WS2016/Hyper-V is known to do this on boot. The problem appears to be that VMCB01 gets irreversibly destroyed during SMM execution. Previously, we used to have 'hsave' VMCB where regular (pre-SMM) L1's state was saved upon nested_svm_vmexit() but now we just switch to VMCB01 from VMCB02.
While writing a selftest for the issue, I've noticed that 'svm->nested.ctl' doesn't get restored after KVM_GET_NESTED_STATE/KVM_SET_NESTED_STATE cycle when guest happens to be in SMM triggered from L2. "KVM: nSVM: Restore nested control upon leaving SMM" is aimed to fix that.
First two patches of the series add missing sanity checks for MSR_VM_HSAVE_PA which has to be page aligned and not zero.
Vitaly Kuznetsov (6): KVM: nSVM: Check the value written to MSR_VM_HSAVE_PA KVM: nSVM: Check that VM_HSAVE_PA MSR was set before VMRUN KVM: nSVM: Introduce svm_copy_nonvmloadsave_state() KVM: nSVM: Fix L1 state corruption upon return from SMM KVM: nSVM: Restore nested control upon leaving SMM KVM: selftests: smm_test: Test SMM enter from L2
arch/x86/kvm/svm/nested.c | 45 +++++++----- arch/x86/kvm/svm/svm.c | 51 +++++++++++++- arch/x86/kvm/svm/svm.h | 4 ++ tools/testing/selftests/kvm/x86_64/smm_test.c | 70 +++++++++++++++++-- 4 files changed, 144 insertions(+), 26 deletions(-)
-- 2.31.1
| |