linux-kernel - Re: [PATCH v8 01/30] KVM: selftests: Add function to allow one-to-one GVA to GPA mappings

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Message-ID: <aJotMWGzChQq41oz@google.com>
Date: Mon, 11 Aug 2025 10:49:37 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Sagi Shahar <sagis@...gle.com>
Cc: linux-kselftest@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>, 
	Shuah Khan <shuah@...nel.org>, Ackerley Tng <ackerleytng@...gle.com>, 
	Ryan Afranji <afranji@...gle.com>, Andrew Jones <ajones@...tanamicro.com>, 
	Isaku Yamahata <isaku.yamahata@...el.com>, Erdem Aktas <erdemaktas@...gle.com>, 
	Rick Edgecombe <rick.p.edgecombe@...el.com>, Roger Wang <runanwang@...gle.com>, 
	Binbin Wu <binbin.wu@...ux.intel.com>, Oliver Upton <oliver.upton@...ux.dev>, 
	"Pratik R. Sampat" <pratikrajesh.sampat@....com>, Reinette Chatre <reinette.chatre@...el.com>, 
	Ira Weiny <ira.weiny@...el.com>, linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: Re: [PATCH v8 01/30] KVM: selftests: Add function to allow one-to-one
 GVA to GPA mappings

On Thu, Aug 07, 2025, Sagi Shahar wrote:
> From: Ackerley Tng <ackerleytng@...gle.com>
> 
> One-to-one GVA to GPA mappings can be used in the guest to set up boot
> sequences during which paging is enabled, hence requiring a transition
> from using physical to virtual addresses in consecutive instructions.

NAK, this is an extremely convoluted way for establishing mappings for hardcoded
boot ranges.  Just use virt_map().  And if clobbering an existing mapping is a
concern, we should add an assert in virt_map() to verify the address is available.