[PATCH 1/5] KVM: arm64: Fix build error in user_mem_abort()

Marc Zyngier
2020-11-06T16:44:40Z

From: Gavin Shan <gshan@redhat.com>

The PUD and PMD are folded into PGD when the following options are
enabled. In that case, PUD_SHIFT is equal to PMD_SHIFT and we fail
to build with the indicated errors:

CONFIG_ARM64_VA_BITS_42=y
CONFIG_ARM64_PAGE_SHIFT=16
CONFIG_PGTABLE_LEVELS=3

arch/arm64/kvm/mmu.c: In function ‘user_mem_abort’:
arch/arm64/kvm/mmu.c:798:2: error: duplicate case value
case PMD_SHIFT:
^~~~
arch/arm64/kvm/mmu.c:791:2: note: previously used here
case PUD_SHIFT:
^~~~

This fixes the issue by skipping the check on PUD huge page when PUD
and PMD are folded into PGD.

Fixes: 2f40c46021bbb ("KVM: arm64: Use fallback mapping sizes for contiguous huge page sizes")
Reported-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201103003009.32955-1-gshan@redhat.com
---
arch/arm64/kvm/mmu.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index c7c6df6309d5..a109c5001827 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -788,10 +788,12 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
}

switch (vma_shift) {
+#ifndef __PAGETABLE_PMD_FOLDED
case PUD_SHIFT:
if (fault_supports_stage2_huge_mapping(memslot, hva, PUD_SIZE))
break;
fallthrough;
+#endif
case CONT_PMD_SHIFT:
vma_shift = PMD_SHIFT;
fallthrough;
--
2.28.0