linux-kernel - [PATCH 4.18 156/168] iommu/amd: Clear memory encryption mask from physical address

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Message-Id: <20181008175625.978463772@linuxfoundation.org>
Date:   Mon,  8 Oct 2018 20:32:16 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Joerg Roedel <joro@...tes.org>,
        iommu@...ts.linux-foundation.org, Borislav Petkov <bp@...e.de>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        kvm@...r.kernel.org, Brijesh Singh <brijesh.singh@....com>,
        Joerg Roedel <jroedel@...e.de>
Subject: [PATCH 4.18 156/168] iommu/amd: Clear memory encryption mask from physical address

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Singh, Brijesh <brijesh.singh@....com>

commit b3e9b515b08e407ab3a026dc2e4d935c48d05f69 upstream.

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().

Fixes: 2543a786aa25 ("iommu/amd: Allow the AMD IOMMU to work with memory encryption")
Reported-by: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc: Tom Lendacky <thomas.lendacky@....com>
Cc: Joerg Roedel <joro@...tes.org>
Cc: <iommu@...ts.linux-foundation.org>
Cc: Borislav Petkov <bp@...e.de>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Radim Krčmář <rkrcmar@...hat.com>
Cc: kvm@...r.kernel.org
Cc: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc: <stable@...r.kernel.org> # 4.14+
Signed-off-by: Brijesh Singh <brijesh.singh@....com>
Signed-off-by: Joerg Roedel <jroedel@...e.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/iommu/amd_iommu.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -3073,7 +3073,7 @@ static phys_addr_t amd_iommu_iova_to_phy
 		return 0;
 
 	offset_mask = pte_pgsize - 1;
-	__pte	    = *pte & PM_ADDR_MASK;
+	__pte	    = __sme_clr(*pte & PM_ADDR_MASK);
 
 	return (__pte & ~offset_mask) | (iova & offset_mask);
 }