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From: "Tian, Kevin" <kevin.tian@intel.com>
To: Paul Durrant <paul.durrant@citrix.com>,
	"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Subject: Re: [PATCH 6/7] vtd: change lookup_page failure semantics
Date: Fri, 21 Sep 2018 00:58:08 +0000	[thread overview]
Message-ID: <AADFC41AFE54684AB9EE6CBC0274A5D1913236F6@SHSMSX101.ccr.corp.intel.com> (raw)
In-Reply-To: <20180920141149.1643-7-paul.durrant@citrix.com>

> From: Paul Durrant [mailto:paul.durrant@citrix.com]
> Sent: Thursday, September 20, 2018 10:12 PM
> 
> Commit 43d1622b "vtd: add lookup_page method to iommu_ops" added a
> lookup method in to the VT-d IOMMU implementation. In some cases (such
> as
> when shared EPT is in operation) that function simply passes back an
> identity MFN (i.e. an MFN with the same value as the DFN that was passed
> in), but this doesn't actually make a lot of sense. If, for instance,
> shared EPT is used then really the function should be doing a P2M lookup
> since DFN space will be identical to GFN space.
> 
> In practice there are no current callers of the lookup_page method and,
> when PV-IOMMU support is added, the method will not be called if either
> shared EPT is in operation or iommu_passthrough is set, so this patch
> simply fails the method with -EOPNOTSUPP in those cases.
> 
> Signed-off-by: Paul Durrant <paul.durrant@citrix.com>

Acked-by: Kevin Tian <kevin.tian@intel.com>

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  reply	other threads:[~2018-09-21  1:00 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-20 14:11 [PATCH 0/7] amd-iommu: cleanup and add lookup_page method Paul Durrant
2018-09-20 14:11 ` [PATCH 1/7] amd-iommu: don't domain_crash() inside map/unmap_page() Paul Durrant
2018-09-20 14:11 ` [PATCH 2/7] amd-iommu: re-name u8/16/32/64 to uint8/16/32/64_t Paul Durrant
2018-09-20 14:11 ` [PATCH 3/7] amd-iommu: convert all bool_t to bool Paul Durrant
2018-09-20 14:11 ` [PATCH 4/7] amd-iommu: reduce code duplication Paul Durrant
2018-09-20 14:11 ` [PATCH 5/7] amd-iommu: introduce new get/set_iommu_pde_info() functions Paul Durrant
2018-09-20 14:11 ` [PATCH 6/7] vtd: change lookup_page failure semantics Paul Durrant
2018-09-21  0:58   ` Tian, Kevin [this message]
2018-09-21 10:16   ` Jan Beulich
2018-09-21 10:18     ` Paul Durrant
2018-09-21 10:27       ` Jan Beulich
2018-09-21 10:31         ` Paul Durrant
2018-09-20 14:11 ` [PATCH 7/7] amd-iommu: add lookup_page method to iommu_ops Paul Durrant
2018-09-20 15:03   ` Jan Beulich
2018-09-20 15:41     ` Paul Durrant

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