KVM: x86/PVM: Check the validity of the root page for direct switchin…

…g when PCID is not supported Similar to the check performed in pvm_set_host_cr3_for_guest_with_host_pcid(), the HPA of the SPT page table for direct switching should also be verified in pvm_set_host_cr3_for_guest_without_host_pcid(). Signed-off-by: Yong He <[email protected]> Signed-off-by: Hou Wenlong <[email protected]> Link: #4
virt-pvm · Apr 10, 2024 · f239d10 · f239d10
1 parent 2932b89
commit f239d10
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/arch/x86/kvm/pvm/pvm.c b/arch/x86/kvm/pvm/pvm.c
@@ -774,9 +774,11 @@ 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) {
-		switch_root = pvm->vcpu.arch.mmu->prev_roots[0].hpa;
+	if (VALID_PAGE(prev_root_hpa) &&
+	    pvm->vcpu.arch.mmu->prev_roots[0].pgd == pvm->msr_switch_cr3) {
+		switch_root = prev_root_hpa;
 		pvm->switch_flags &= ~SWITCH_FLAGS_NO_DS_CR3;
 	} else {
 		pvm->switch_flags |= SWITCH_FLAGS_NO_DS_CR3;