fix: kernel panic on AMD CPUs

loopholelabs · Mar 19, 2024 · 28bf0d2 · 28bf0d2
1 parent ebec6f6
commit 28bf0d2
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/arch/x86/kvm/pvm/pvm.c b/arch/x86/kvm/pvm/pvm.c
@@ -765,8 +765,9 @@ static void pvm_set_host_cr3_for_guest_without_host_pcid(struct vcpu_pvm *pvm)
 {
 	u64 root_hpa = pvm->vcpu.arch.mmu->root.hpa;
 	u64 switch_root = 0;
+	u64 prev_root_hpa = pvm->vcpu.arch.mmu->prev_roots[0].hpa;
 
-	if (pvm->vcpu.arch.mmu->prev_roots[0].pgd == pvm->msr_switch_cr3) {
+	if (VALID_PAGE(prev_root_hpa) && (pvm->vcpu.arch.mmu->prev_roots[0].pgd == pvm->msr_switch_cr3)) {
 		switch_root = pvm->vcpu.arch.mmu->prev_roots[0].hpa;
 		pvm->switch_flags &= ~SWITCH_FLAGS_NO_DS_CR3;
 	} else {