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From: Catalin Marinas <catalin.marinas@arm.com>
To: Christoffer Dall <christoffer.dall@linaro.org>
Cc: "linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [PATCH 2/2] arm/arm64: KVM: Ensure memslots are within KVM_PHYS_SIZE
Date: Tue, 30 Sep 2014 13:46:51 +0100	[thread overview]
Message-ID: <20140930124651.GC12702@e104818-lin.cambridge.arm.com> (raw)
In-Reply-To: <1411674174-30672-3-git-send-email-christoffer.dall@linaro.org>

On Thu, Sep 25, 2014 at 08:42:54PM +0100, Christoffer Dall wrote:
> When creating or moving a memslot, make sure the IPA space is within the
> addressable range of the guest.  Otherwise, user space can create too
> large a memslot and KVM would try to access potentially unallocated page
> table entries when inserting entries in the Stage-2 page tables.
> 
> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
> ---
>  arch/arm/kvm/mmu.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
> index 4532f5f..52a311a 100644
> --- a/arch/arm/kvm/mmu.c
> +++ b/arch/arm/kvm/mmu.c
> @@ -975,6 +975,9 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run)
>  		goto out_unlock;
>  	}
>  
> +	/* Userspace should not be able to register out-of-bounds IPAs */

I think "userspace" is a bit misleading (should be "guests").

> +	VM_BUG_ON(fault_ipa >= KVM_PHYS_SIZE);

Can guests not generate IPA addresses higher than KVM_PHYS_SIZE? I don't
see why this wouldn't be possible when PARange > 40.

-- 
Catalin

WARNING: multiple messages have this Message-ID (diff)
From: catalin.marinas@arm.com (Catalin Marinas)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/2] arm/arm64: KVM: Ensure memslots are within KVM_PHYS_SIZE
Date: Tue, 30 Sep 2014 13:46:51 +0100	[thread overview]
Message-ID: <20140930124651.GC12702@e104818-lin.cambridge.arm.com> (raw)
In-Reply-To: <1411674174-30672-3-git-send-email-christoffer.dall@linaro.org>

On Thu, Sep 25, 2014 at 08:42:54PM +0100, Christoffer Dall wrote:
> When creating or moving a memslot, make sure the IPA space is within the
> addressable range of the guest.  Otherwise, user space can create too
> large a memslot and KVM would try to access potentially unallocated page
> table entries when inserting entries in the Stage-2 page tables.
> 
> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
> ---
>  arch/arm/kvm/mmu.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
> index 4532f5f..52a311a 100644
> --- a/arch/arm/kvm/mmu.c
> +++ b/arch/arm/kvm/mmu.c
> @@ -975,6 +975,9 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run)
>  		goto out_unlock;
>  	}
>  
> +	/* Userspace should not be able to register out-of-bounds IPAs */

I think "userspace" is a bit misleading (should be "guests").

> +	VM_BUG_ON(fault_ipa >= KVM_PHYS_SIZE);

Can guests not generate IPA addresses higher than KVM_PHYS_SIZE? I don't
see why this wouldn't be possible when PARange > 40.

-- 
Catalin

  reply	other threads:[~2014-09-30 12:47 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-25 19:42 [PATCH 0/2] arm/arm64: KVM: Host 48-bit VA support and IPA limits Christoffer Dall
2014-09-25 19:42 ` Christoffer Dall
2014-09-25 19:42 ` [PATCH 1/2] arm64: KVM: Implement 48 VA support for KVM EL2 and Stage-2 Christoffer Dall
2014-09-25 19:42   ` Christoffer Dall
2014-09-26 14:08   ` Jungseok Lee
2014-09-26 14:08     ` Jungseok Lee
2014-09-30 12:39   ` Catalin Marinas
2014-09-30 12:39     ` Catalin Marinas
2014-10-06 13:41     ` Christoffer Dall
2014-10-06 13:41       ` Christoffer Dall
2014-10-06 15:54       ` Catalin Marinas
2014-10-06 15:54         ` Catalin Marinas
2014-10-06 19:54         ` Christoffer Dall
2014-10-06 19:54           ` Christoffer Dall
2014-09-25 19:42 ` [PATCH 2/2] arm/arm64: KVM: Ensure memslots are within KVM_PHYS_SIZE Christoffer Dall
2014-09-25 19:42   ` Christoffer Dall
2014-09-30 12:46   ` Catalin Marinas [this message]
2014-09-30 12:46     ` Catalin Marinas
2014-10-06 13:47     ` Christoffer Dall
2014-10-06 13:47       ` Christoffer Dall
2014-10-06 16:02       ` Catalin Marinas
2014-10-06 16:02         ` Catalin Marinas

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