From: Paolo Bonzini <pbonzini@redhat.com>
To: Sean Christopherson <seanjc@google.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
vkuznets@redhat.com, mlevitsk@redhat.com, dmatlack@google.com
Subject: Re: [PATCH 09/12] KVM: MMU: look for a cached PGD when going from 32-bit to 64-bit
Date: Fri, 11 Feb 2022 12:45:20 +0100 [thread overview]
Message-ID: <51fcfb88-417b-e638-78b7-bbca82d8bd8b@redhat.com> (raw)
In-Reply-To: <YgW8ySdRSWjPvOQx@google.com>
On 2/11/22 02:32, Sean Christopherson wrote:
> Maybe cached_root_find_and_rotate() or cached_root_find_and_age()?
I'll go for cached_root_find_and_keep_current() and
cached_root_find_without_current(), respectively.
>
> Hmm, while we're refactoring this, I'd really prefer we not grab vcpu->arch.mmu
> way down in the helpers. @vcpu is needed only for the request, so what about
> doing this?
>
> if (!fast_pgd_switch(vcpu, new_pgd, new_role)) {
> /*
> * <whatever kvm_mmu_reload() becomes> will set up a new root
> * prior to the next VM-Enter. Free the current root if it's
> * valid, i.e. if a valid root was evicted from the cache.
> */
> if (VALID_PAGE(vcpu->arch.mmu->root.hpa))
> kvm_mmu_free_roots(vcpu, vcpu->arch.mmu, KVM_MMU_ROOT_CURRENT);
> return;
> }
I tried, but it's much easier to describe the cache functions if their
common postcondition is "vcpu->arch.mmu->root.hpa is never stale"; which
requires not a struct kvm_vcpu* but at least a struct kvm*, for the MMU
lock.
I could change kvm_mmu_free_roots and cached_root_* to take a struct
kvm* plus a struct kvm_mmu*. Does that sound better?
Paolo
next prev parent reply other threads:[~2022-02-11 11:45 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-09 17:00 [PATCH 00/12] KVM: MMU: do not unload MMU roots on all role changes Paolo Bonzini
2022-02-09 17:00 ` [PATCH 01/12] KVM: x86: host-initiated EFER.LME write affects the MMU Paolo Bonzini
2022-02-10 22:49 ` Sean Christopherson
2022-02-09 17:00 ` [PATCH 02/12] KVM: MMU: move MMU role accessors to header Paolo Bonzini
2022-02-10 23:00 ` Sean Christopherson
2022-02-09 17:00 ` [PATCH 03/12] KVM: x86: do not deliver asynchronous page faults if CR0.PG=0 Paolo Bonzini
2022-02-10 23:10 ` Sean Christopherson
2022-02-10 23:14 ` Sean Christopherson
2022-02-10 23:16 ` Sean Christopherson
2022-02-11 11:16 ` Paolo Bonzini
2022-02-09 17:00 ` [PATCH 04/12] KVM: MMU: WARN if PAE roots linger after kvm_mmu_unload Paolo Bonzini
2022-02-10 23:20 ` Sean Christopherson
2022-02-11 11:18 ` Paolo Bonzini
2022-02-09 17:00 ` [PATCH 05/12] KVM: MMU: avoid NULL-pointer dereference on page freeing bugs Paolo Bonzini
2022-02-11 0:24 ` Sean Christopherson
2022-02-11 11:21 ` Paolo Bonzini
2022-02-09 17:00 ` [PATCH 06/12] KVM: MMU: rename kvm_mmu_reload Paolo Bonzini
2022-02-11 0:27 ` Sean Christopherson
2022-02-11 10:07 ` Paolo Bonzini
2022-02-11 16:16 ` Sean Christopherson
2022-02-11 16:52 ` Paolo Bonzini
2022-02-09 17:00 ` [PATCH 07/12] KVM: x86: use struct kvm_mmu_root_info for mmu->root Paolo Bonzini
2022-02-11 17:39 ` Sean Christopherson
2022-02-09 17:00 ` [PATCH 08/12] KVM: MMU: do not consult levels when freeing roots Paolo Bonzini
2022-02-11 0:41 ` Sean Christopherson
2022-02-11 0:54 ` Sean Christopherson
2022-02-11 1:07 ` Paolo Bonzini
2022-02-11 1:35 ` Sean Christopherson
2022-02-11 1:44 ` Sean Christopherson
2022-02-11 2:20 ` Sean Christopherson
2022-02-09 17:00 ` [PATCH 09/12] KVM: MMU: look for a cached PGD when going from 32-bit to 64-bit Paolo Bonzini
2022-02-11 1:32 ` Sean Christopherson
2022-02-11 1:37 ` Sean Christopherson
2022-02-11 10:09 ` Paolo Bonzini
2022-02-11 11:45 ` Paolo Bonzini [this message]
2022-02-11 17:38 ` Sean Christopherson
2022-02-09 17:00 ` [PATCH 10/12] KVM: MMU: load new PGD after the shadow MMU is initialized Paolo Bonzini
2022-02-11 17:45 ` Sean Christopherson
2022-02-11 17:47 ` Paolo Bonzini
2022-02-09 17:00 ` [PATCH 11/12] KVM: MMU: remove kvm_mmu_calc_root_page_role Paolo Bonzini
2022-02-11 17:53 ` Sean Christopherson
2022-02-09 17:00 ` [PATCH 12/12] KVM: x86: do not unload MMU roots on all role changes Paolo Bonzini
2022-02-11 9:08 ` Nikunj A. Dadhania
2022-02-11 18:48 ` Sean Christopherson
2022-02-14 16:34 ` Paolo Bonzini
2022-02-14 19:24 ` Sean Christopherson
2022-02-15 8:17 ` Paolo Bonzini
2022-02-09 17:07 ` [PATCH 00/12] KVM: MMU: " Sean Christopherson
2022-02-09 17:11 ` Paolo Bonzini
2022-02-09 17:16 ` Sean Christopherson
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