linux-kernel - Re: [PATCH 00/10] KVM: Clean up 'struct page' / pfn helpers

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Date:   Thu, 16 Jun 2022 17:21:26 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 00/10] KVM: Clean up 'struct page' / pfn helpers

On 4/29/22 03:04, Sean Christopherson wrote:
> Clean up KVM's struct page / pfn helpers to reduce the number of
> pfn_to_page() and page_to_pfn() conversions.  E.g. kvm_release_pfn_dirty()
> makes 6 (if I counted right) calls to pfn_to_page() when releasing a dirty
> pfn that backed by a vanilla struct page.  That is easily trimmed down to
> a single call.
> 
> And perhaps more importantly, rename and refactor kvm_is_reserved_pfn() to
> try and better reflect what it actually queries, which at this point is
> effectively whether or not the pfn is backed by a refcounted page.
> 
> Sean Christopherson (10):
>    KVM: Do not zero initialize 'pfn' in hva_to_pfn()
>    KVM: Drop bogus "pfn != 0" guard from kvm_release_pfn()
>    KVM: Don't set Accessed/Dirty bits for ZERO_PAGE
>    KVM: Avoid pfn_to_page() and vice versa when releasing pages
>    KVM: nVMX: Use kvm_vcpu_map() to get/pin vmcs12's APIC-access page
>    KVM: Don't WARN if kvm_pfn_to_page() encounters a "reserved" pfn
>    KVM: Remove kvm_vcpu_gfn_to_page() and kvm_vcpu_gpa_to_page()
>    KVM: Take a 'struct page', not a pfn in kvm_is_zone_device_page()
>    KVM: Rename/refactor kvm_is_reserved_pfn() to
>      kvm_pfn_to_refcounted_page()
>    KVM: x86/mmu: Shove refcounted page dependency into
>      host_pfn_mapping_level()
> 
>   arch/x86/kvm/mmu/mmu.c     |  26 +++++--
>   arch/x86/kvm/mmu/tdp_mmu.c |   3 +-
>   arch/x86/kvm/vmx/nested.c  |  39 ++++-------
>   arch/x86/kvm/vmx/vmx.h     |   2 +-
>   include/linux/kvm_host.h   |  12 +---
>   virt/kvm/kvm_main.c        | 140 +++++++++++++++++++++++++------------
>   6 files changed, 131 insertions(+), 91 deletions(-)
> 
> 
> base-commit: 2a39d8b39bffdaf1a4223d0d22f07baee154c8f3

Queued, thanks.

Paolo