linux-kernel - Re: [PATCH] iommu/amd: Clear memory encryption mask from physical address

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Message-ID: <20181005083101.GD3630@8bytes.org>
Date:   Fri, 5 Oct 2018 10:31:01 +0200
From:   Joerg Roedel <joro@...tes.org>
To:     "Singh, Brijesh" <brijesh.singh@....com>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
        "Lendacky, Thomas" <Thomas.Lendacky@....com>,
        Borislav Petkov <bp@...e.de>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        "# 4 . 14+" <stable@...r.kernel.org>
Subject: Re: [PATCH] iommu/amd: Clear memory encryption mask from physical
 address

On Thu, Oct 04, 2018 at 09:40:23PM +0000, Singh, Brijesh wrote:
> Boris Ostrovsky reported a memory leak with device passthrough when SME
> is active.
> 
> The VFIO driver uses iommu_iova_to_phys() to get the physical address for
> an iova. This physical address is later passed into vfio_unmap_unpin() to
> unpin the memory. The vfio_unmap_unpin() uses pfn_valid() before unpinning
> the memory. The pfn_valid() check was failing because encryption mask was
> part of the physical address returned. This resulted in the memory not
> being unpinned and therefore leaked after the guest terminates.
> 
> The memory encryption mask must be cleared from the physical address in
> iommu_iova_to_phys().

Merged and on its way upstream, thanks Brijesh.