diff mbox series

[RFC,v2,06/10] KVM: arm64: Skip VMA checks for slots without userspace address

Message ID 20240801090117.3841080-7-tabba@google.com (mailing list archive)
State New
Headers show
Series KVM: Restricted mapping of guest_memfd at the host and pKVM/arm64 support | expand

Commit Message

Fuad Tabba Aug. 1, 2024, 9:01 a.m. UTC 
Memory slots backed by guest memory might be created with no
intention of being mapped by the host. These are recognized by
not having a userspace address in the memory slot.

VMA checks are neither possible nor necessary for this kind of
slot, so skip them.

Signed-off-by: Fuad Tabba <tabba@google.com>
---
 arch/arm64/kvm/mmu.c | 8 ++++++++
 1 file changed, 8 insertions(+)
diff mbox series

Patch

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 8bcab0cc3fe9..e632e10ea395 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -948,6 +948,10 @@  static void stage2_unmap_memslot(struct kvm *kvm,
 	phys_addr_t size = PAGE_SIZE * memslot->npages;
 	hva_t reg_end = hva + size;
 
+	/* Host will not map this private memory without a userspace address. */
+	if (kvm_slot_can_be_private(memslot) && !hva)
+		return;
+
 	/*
 	 * A memory region could potentially cover multiple VMAs, and any holes
 	 * between them, so iterate over all of them to find out if we should
@@ -1976,6 +1980,10 @@  int kvm_arch_prepare_memory_region(struct kvm *kvm,
 	hva = new->userspace_addr;
 	reg_end = hva + (new->npages << PAGE_SHIFT);
 
+	/* Host will not map this private memory without a userspace address. */
+	if ((kvm_slot_can_be_private(new)) && !hva)
+		return 0;
+
 	mmap_read_lock(current->mm);
 	/*
 	 * A memory region could potentially cover multiple VMAs, and any holes