[PATCH 02/16] KVM: arm64: Don't issue CMOs when the physical address is invalid

From: Marc Zyngier
Date: Thu Jul 15 2021 - 12:32:25 EST


Make sure we don't issue CMOs when mapping something that
is not a memory address in the S2 page tables.

Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
arch/arm64/kvm/hyp/pgtable.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 05321f4165e3..a5874ebd0354 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -619,12 +619,16 @@ static int stage2_map_walker_try_leaf(u64 addr, u64 end, u32 level,
}

/* Perform CMOs before installation of the guest stage-2 PTE */
- if (mm_ops->dcache_clean_inval_poc && stage2_pte_cacheable(pgt, new))
- mm_ops->dcache_clean_inval_poc(kvm_pte_follow(new, mm_ops),
- granule);
-
- if (mm_ops->icache_inval_pou && stage2_pte_executable(new))
- mm_ops->icache_inval_pou(kvm_pte_follow(new, mm_ops), granule);
+ if (kvm_phys_is_valid(phys)) {
+ if (mm_ops->dcache_clean_inval_poc &&
+ stage2_pte_cacheable(pgt, new))
+ mm_ops->dcache_clean_inval_poc(kvm_pte_follow(new,
+ mm_ops),
+ granule);
+ if (mm_ops->icache_inval_pou && stage2_pte_executable(new))
+ mm_ops->icache_inval_pou(kvm_pte_follow(new, mm_ops),
+ granule);
+ }

smp_store_release(ptep, new);
if (stage2_pte_is_counted(new))
--
2.30.2