Thread (99 messages) 99 messages, 4 authors, 2024-10-25
STALE595d

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

From: Sean Christopherson <seanjc@google.com>
Date: 2024-10-10 18:26:45
Also in: kvm, kvm-riscv, kvmarm, linux-arm-kernel, linux-mips, linux-riscv, lkml, loongarch
Subsystem: kernel virtual machine for powerpc (kvm/powerpc), linux for powerpc (32-bit and 64-bit), the rest · Maintainers: Madhavan Srinivasan, Michael Ellerman, Linus Torvalds

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

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