[PATCH][stable-4.{4,9,14,19}] KVM: arm64: Fix exclusive limit for IPA size

[PATCH][stable-4.{4,9,14,19}] KVM: arm64: Fix exclusive limit for IPA size

[Marc Zyngier]

Commit 262b003d059c6671601a19057e9fe1a5e7f23722 upstream.

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: 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 # 4.4, 4.9, 4.14, 4.19
Reviewed-by: Andrew Jones <drjones@redhat.com>
Link: https://lore.kernel.org/r/20210311100016.3830038-3-maz@kernel.org
---
 virt/kvm/arm/mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index 787f7329d1b7..11103b75c596 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -2080,7 +2080,7 @@ 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 >=
+	if (memslot->base_gfn + memslot->npages >
 	    (KVM_PHYS_SIZE >> PAGE_SHIFT))
 		return -EFAULT;
 
-- 
2.29.2

Re: [PATCH][stable-4.{4,9,14,19}] KVM: arm64: Fix exclusive limit for IPA size

[Greg KH]

On Mon, Mar 15, 2021 at 11:08:33AM +0000, Marc Zyngier wrote:
> Commit 262b003d059c6671601a19057e9fe1a5e7f23722 upstream.
> 
> 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: 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 # 4.4, 4.9, 4.14, 4.19
> Reviewed-by: Andrew Jones <drjones@redhat.com>
> Link: https://lore.kernel.org/r/20210311100016.3830038-3-maz@kernel.org
> ---
>  virt/kvm/arm/mmu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

This file does not exist in 4.4.y or 4.9.y, so I can't apply it there :(

Queued up everywhere else, and also the other backports you sent,
thanks.

gre gk-h

Re: [PATCH][stable-4.{4,9,14,19}] KVM: arm64: Fix exclusive limit for IPA size

[Marc Zyngier]

On 2021-03-15 11:30, Greg KH wrote:
> On Mon, Mar 15, 2021 at 11:08:33AM +0000, Marc Zyngier wrote:
>> Commit 262b003d059c6671601a19057e9fe1a5e7f23722 upstream.
>> 
>> 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: 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 # 4.4, 4.9, 4.14, 4.19
>> Reviewed-by: Andrew Jones <drjones@redhat.com>
>> Link: 
>> https://lore.kernel.org/r/20210311100016.3830038-3-maz@kernel.org
>> ---
>>  virt/kvm/arm/mmu.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> This file does not exist in 4.4.y or 4.9.y, so I can't apply it there 
> :(

Ah, git rename handling fixed that up for me, and I didn't pay
attention to the resulting path... Sorry about that.

I'll resend the patch for 4.4 and 4.9

Thanks,

         M.
-- 
Jazz is not dead. It just smells funny...