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UPSTREAM: KVM: arm64: Fix exclusive limit for IPA size

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When registering a memslot, we check the size and location of that
memslot against the IPA size to ensure that we can provide guest
access to the whole of the memory.

Unfortunately, this check rejects memslot that end-up at the exact
limit of the addressing capability for a given IPA size. For example,
it refuses the creation of a 2GB memslot at 0x8000000 with a 32bit
IPA space.

Fix it by relaxing the check to accept a memslot reaching the
limit of the IPA space.

Fixes: c3058d5da2 ("arm/arm64: KVM: Ensure memslots are within KVM_PHYS_SIZE")
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Reviewed-by: Andrew Jones <drjones@redhat.com>
Link: https://lore.kernel.org/r/20210311100016.3830038-3-maz@kernel.org
(cherry picked from commit 262b003d05)
Signed-off-by: Will Deacon <willdeacon@google.com>
Bug: 178098380
Test: atest VirtualizationHostTestCases on an EL2-enabled device
Change-Id: I82fcfb372b375c2e35997fdc4b33dbd33f056887
This commit is contained in:
Marc Zyngier
2021-03-11 10:00:16 +00:00
committed by Will Deacon
parent ac821b6257
commit a128ec2b2e
1 changed files with 1 additions and 2 deletions
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3
arch/arm64/kvm/mmu.c
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@@ -1312,8 +1312,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
* Prevent userspace from creating a memory region outside of the IPA
* space addressable by the KVM guest IPA space.
*/
if (memslot->base_gfn + memslot->npages >=
(kvm_phys_size(kvm) >> PAGE_SHIFT))
if ((memslot->base_gfn + memslot->npages) > (kvm_phys_size(kvm) >> PAGE_SHIFT))
return -EFAULT;
mmap_read_lock(current->mm);