[PATCH] KVM: arm64: Release mmap_lock when using VM_SHARED with MTE
From: Quentin Perret <hidden>
Date: 2021-10-05 12:20:40
Also in:
kvmarm, lkml
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
VM_SHARED mappings are currently forbidden in a memslot with MTE to
prevent two VMs racing to sanitise the same page. However, this check
is performed while holding current->mm's mmap_lock, but fails to release
it. Fix this by releasing the lock when needed.
Fixes: ea7fc1bb1cd1 ("KVM: arm64: Introduce MTE VM feature")
Signed-off-by: Quentin Perret <redacted>
---
arch/arm64/kvm/mmu.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 1a94a7ca48f2..69bd1732a299 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c@@ -1529,8 +1529,10 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, * when updating the PG_mte_tagged page flag, see * sanitise_mte_tags for more details. */ - if (kvm_has_mte(kvm) && vma->vm_flags & VM_SHARED) - return -EINVAL; + if (kvm_has_mte(kvm) && vma->vm_flags & VM_SHARED) { + ret = -EINVAL; + break; + } if (vma->vm_flags & VM_PFNMAP) { /* IO region dirty page logging not allowed */
--
2.33.0.800.g4c38ced690-goog
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