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: e55cac5bf2a9 ("kvm: arm/arm64: Prepare for VM specific stage2 translations") Reviewed-by: Eric Auger eric.auger@redhat.com Signed-off-by: Marc Zyngier maz@kernel.org Cc: stable@vger.kernel.org --- arch/arm64/kvm/mmu.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 77cb2d28f2a4..8711894db8c2 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -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);
On Thu, Mar 11, 2021 at 10:00:16AM +0000, Marc Zyngier wrote:
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: e55cac5bf2a9 ("kvm: arm/arm64: Prepare for VM specific stage2 translations")
Isn't this actually fixing commit c3058d5da222 ("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
arch/arm64/kvm/mmu.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 77cb2d28f2a4..8711894db8c2 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -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); -- 2.29.2
Otherwise
Reviewed-by: Andrew Jones drjones@redhat.com
Thanks, drew
On 2021-03-11 11:15, Andrew Jones wrote:
On Thu, Mar 11, 2021 at 10:00:16AM +0000, Marc Zyngier wrote:
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: e55cac5bf2a9 ("kvm: arm/arm64: Prepare for VM specific stage2 translations")
Isn't this actually fixing commit c3058d5da222 ("arm/arm64: KVM: Ensure memslots are within KVM_PHYS_SIZE") ?
Ah, yes, that's indeed better (more backport work... ;-)
Thanks,
M.
linux-stable-mirror@lists.linaro.org
-
Andrew Jones -
Marc Zyngier