[PATCH v13 53/85] KVM: PPC: e500: Mark "struct page" pfn accessed before dropping mmu_lock

Sean Christopherson
2024-10-10T18:26:45Z

Mark pages accessed before dropping mmu_lock when faulting in guest memory
so that shadow_map() can convert to kvm_release_faultin_page() without
tripping its lockdep assertion on mmu_lock being held. Marking pages
accessed outside of mmu_lock is ok (not great, but safe), but marking
pages _dirty_ outside of mmu_lock can make filesystems unhappy.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/powerpc/kvm/e500_mmu_host.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c
index 5c2adfd19e12..334dd96f8081 100644
--- a/arch/powerpc/kvm/e500_mmu_host.c
+++ b/arch/powerpc/kvm/e500_mmu_host.c
@@ -498,11 +498,9 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
kvmppc_mmu_flush_icache(pfn);

out:
- spin_unlock(&kvm->mmu_lock);
-
/* Drop refcount on page, so that mmu notifiers can clear it */
kvm_release_pfn_clean(pfn);
-
+ spin_unlock(&kvm->mmu_lock);
return ret;
}

--
2.47.0.rc1.288.g06298d1525-goog