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From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <jbeulich@suse.com>,
	"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: Paul Durrant <paul@xen.org>
Subject: Re: [PATCH v7 4/8] AMD/IOMMU: check IVMD ranges against host implementation limits
Date: Thu, 26 Aug 2021 14:16:17 +0100	[thread overview]
Message-ID: <05d3fb35-ed58-7b3b-59a7-fb555953cfca@citrix.com> (raw)
In-Reply-To: <c0b49a0e-44fa-4e15-ffb9-d49002060edf@suse.com>

On 26/08/2021 08:24, Jan Beulich wrote:
> When such ranges can't be represented as 1:1 mappings in page tables,
> reject them as presumably bogus. Note that when we detect features late
> (because of EFRSup being clear in the ACPI tables), it would be quite a
> bit of work to check for (and drop) out of range IVMD ranges, so IOMMU
> initialization gets failed in this case instead.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> Reviewed-by: Paul Durrant <paul@xen.org>

I'm not certain this is correct in combination with memory encryption.

The upper bits are the KeyID, but we shouldn't find any of those set in
an IVMD range.  I think at a minimum, we need to reduce the address
check by the stolen bits for encryption, which gives a lower bound.

~Andrew



  reply	other threads:[~2021-08-26 13:16 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-26  7:21 [PATCH v7] AMD/IOMMU: further work split from XSA-378 Jan Beulich
2021-08-26  7:23 ` [PATCH v7 1/8] AMD/IOMMU: check / convert IVMD ranges for being / to be reserved Jan Beulich
2021-08-26 12:10   ` Andrew Cooper
2021-08-26 12:31     ` Jan Beulich
2021-09-21  7:37       ` Jan Beulich
2021-08-26  7:23 ` [PATCH v7 2/8] AMD/IOMMU: obtain IVHD type to use earlier Jan Beulich
2021-08-26 12:30   ` Andrew Cooper
2021-08-26 12:33     ` Jan Beulich
2021-08-26  7:23 ` [PATCH v7 3/8] AMD/IOMMU: improve (extended) feature detection Jan Beulich
2021-08-26 13:02   ` Andrew Cooper
2021-08-26 13:13     ` Jan Beulich
2021-08-26  7:24 ` [PATCH v7 4/8] AMD/IOMMU: check IVMD ranges against host implementation limits Jan Beulich
2021-08-26 13:16   ` Andrew Cooper [this message]
2021-08-26 14:03     ` Jan Beulich
2021-08-26  7:24 ` [PATCH v7 5/8] AMD/IOMMU: also insert IVMD ranges into Dom0's page tables Jan Beulich
2021-08-26  7:25 ` [PATCH v7 6/8] AMD/IOMMU: provide function backing XENMEM_reserved_device_memory_map Jan Beulich
2021-08-26 13:24   ` Andrew Cooper
2021-08-26 14:05     ` Jan Beulich
2021-08-26  7:25 ` [PATCH v7 7/8] AMD/IOMMU: add "ivmd=" command line option Jan Beulich
2021-08-26 14:08   ` Andrew Cooper
2021-08-26 14:30     ` Jan Beulich
2021-08-26  7:26 ` [PATCH v7 8/8] AMD/IOMMU: respect AtsDisabled device flag Jan Beulich
2021-08-26 14:27   ` Andrew Cooper
2021-08-26 14:33     ` Jan Beulich

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