From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Christoph Hellwig <hch@infradead.org>, iommu@lists.linux-foundation.org
Subject: Memory clearing in swiotlb_update_mem_attributes()
Date: Wed, 5 Jan 2022 01:49:39 +0300 [thread overview]
Message-ID: <20220104224939.yhpceiuzqqhb72ql@box.shutemov.name> (raw)
Hi Tom,
For larger TDX VM, memset() after set_memory_decrypted() in
swiotlb_update_mem_attributes() takes substantial portion of boot time.
It makes me wounder why do we need it there? Malicious VMM can mess with
decrypted/shared buffer at any point and for normal use it will be
populated with real data anyway.
Can we drop it?
--
Kirill A. Shutemov
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next reply other threads:[~2022-01-04 22:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-04 22:49 Kirill A. Shutemov [this message]
2022-01-05 14:06 ` Memory clearing in swiotlb_update_mem_attributes() Tom Lendacky via iommu
2022-01-05 14:12 ` Christoph Hellwig
2022-01-05 15:58 ` Kirill A. Shutemov
2022-01-10 15:58 ` Tom Lendacky via iommu
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