linux-kernel - Re: [PATCH v4 1/3] x86/hyperv: Use slow_virt_to_phys() in page transition hypervisor callback

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Message-ID: <20240117133727.3zzwifnunmgklotw@box.shutemov.name>
Date: Wed, 17 Jan 2024 16:37:27 +0300
From: kirill.shutemov@...ux.intel.com
To: mhklinux@...look.com
Cc: tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
	dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com,
	haiyangz@...rosoft.com, wei.liu@...nel.org, decui@...rosoft.com,
	luto@...nel.org, peterz@...radead.org, akpm@...ux-foundation.org,
	urezki@...il.com, hch@...radead.org, lstoakes@...il.com,
	thomas.lendacky@....com, ardb@...nel.org, jroedel@...e.de,
	seanjc@...gle.com, rick.p.edgecombe@...el.com,
	sathyanarayanan.kuppuswamy@...ux.intel.com,
	linux-kernel@...r.kernel.org, linux-coco@...ts.linux.dev,
	linux-hyperv@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH v4 1/3] x86/hyperv: Use slow_virt_to_phys() in page
 transition hypervisor callback

On Mon, Jan 15, 2024 at 06:20:06PM -0800, mhkelley58@...il.com wrote:
> From: Michael Kelley <mhklinux@...look.com>
> 
> In preparation for temporarily marking pages not present during a
> transition between encrypted and decrypted, use slow_virt_to_phys()
> in the hypervisor callback. As long as the PFN is correct,
> slow_virt_to_phys() works even if the leaf PTE is not present.
> The existing functions that depend on vmalloc_to_page() all
> require that the leaf PTE be marked present, so they don't work.
> 
> Update the comments for slow_virt_to_phys() to note this broader usage
> and the requirement to work even if the PTE is not marked present.
> 
> Signed-off-by: Michael Kelley <mhklinux@...look.com>

Acked-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>

-- 
  Kiryl Shutsemau / Kirill A. Shutemov