[PATCH 07/20] [Bionic] (upstream) KVM: PPC: Book3S HV: Make radix clear pte when unmapping

[Leonardo Bras]

From: Nicholas Piggin <npiggin at gmail.com>

BugLink: https://bugs.launchpad.net/bugs/1788098

The current partition table unmap code clears the _PAGE_PRESENT bit
out of the pte, which leaves pud_huge/pmd_huge true and does not
clear pud_present/pmd_present.  This can confuse subsequent page
faults and possibly lead to the guest looping doing continual
hypervisor page faults.

Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
Signed-off-by: Paul Mackerras <paulus at ozlabs.org>
(cherry picked from commit 7e3d9a1d0f2c681456a2e04b8ba9a2fb448fe515 v4.19)
Signed-off-by: Leonardo Bras <leonardo at linux.ibm.com>
---
 arch/powerpc/kvm/book3s_64_mmu_radix.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index a6870288c0e0..361f42c8c73e 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -584,7 +584,7 @@ int kvm_unmap_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
 
 	ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
 	if (ptep && pte_present(*ptep)) {
-		old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_PRESENT, 0,
+		old = kvmppc_radix_update_pte(kvm, ptep, ~0UL, 0,
 					      gpa, shift);
 		kvmppc_radix_tlbie_page(kvm, gpa, shift);
 		if ((old & _PAGE_DIRTY) && memslot->dirty_bitmap) {
-- 
2.20.1