From: Paolo Bonzini <pbonzini@redhat.com>
To: Sean Christopherson <seanjc@google.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
dmatlack@google.com, vkuznets@redhat.com
Subject: Re: [PATCH 07/23] KVM: MMU: remove kvm_mmu_calc_root_page_role
Date: Thu, 10 Feb 2022 18:43:00 +0100 [thread overview]
Message-ID: <88d3f309-9424-9035-b2ef-88c5d7fb088f@redhat.com> (raw)
In-Reply-To: <YgVLkgwBRy+JXZiH@google.com>
On 2/10/22 18:29, Sean Christopherson wrote:
> On Thu, Feb 10, 2022, Paolo Bonzini wrote:
>> On 2/10/22 01:47, Sean Christopherson wrote:
>>> The nested mess is likely easily solved, I don't see any obvious issue with swapping
>>> the order. But I still don't love the subtlety. I do like shaving cycles, just
>>> not the subtlety...
>>
>> Not so easily, but it's doable and it's essentially what I did in the other
>> series (the one that reworks the root cache).
>
> Sounds like I should reveiw that series first?
Yeah, this one is still a nice step in the direction of guest pt walk
from shadow pt build(*), but with no immediate use for TDP MMU root reuse.
The original idea was to use the MMU role to decide whether to do
kvm_mmu_unload(), but that would have still been a bandaid---inefficient
and a bad idea overall. Patches 6+7 of this series (once fixed, because
they were buggy as hell) turned out to be enough to tame the PGD cache
and remove kvm_mmu_unload() altogether from kvm_mmu_reset_context().
Paolo
(*) Your idea of detecting stale roots is quite easily implemented on
top of these, for example, because a root is stale if and only if the
root_role changes.
next prev parent reply other threads:[~2022-02-10 17:43 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-04 11:56 [PATCH 00/23] KVM: MMU: MMU role refactoring Paolo Bonzini
2022-02-04 11:56 ` [PATCH 01/23] KVM: MMU: pass uses_nx directly to reset_shadow_zero_bits_mask Paolo Bonzini
2022-02-04 17:59 ` David Matlack
2022-02-05 14:52 ` Paolo Bonzini
2022-02-07 16:09 ` Sean Christopherson
2022-02-07 21:50 ` David Matlack
2022-02-10 0:30 ` Sean Christopherson
2022-02-10 16:38 ` Paolo Bonzini
2022-02-04 11:56 ` [PATCH 02/23] KVM: MMU: nested EPT cannot be used in SMM Paolo Bonzini
2022-02-04 18:16 ` David Matlack
2022-02-09 22:43 ` Sean Christopherson
2022-02-04 11:56 ` [PATCH 03/23] KVM: MMU: remove valid from extended role Paolo Bonzini
2022-02-04 18:32 ` David Matlack
2022-02-05 14:50 ` Paolo Bonzini
2022-02-09 22:54 ` Sean Christopherson
2022-02-10 9:53 ` Paolo Bonzini
2022-02-04 11:56 ` [PATCH 04/23] KVM: MMU: constify uses of struct kvm_mmu_role_regs Paolo Bonzini
2022-02-04 18:41 ` David Matlack
2022-02-09 22:57 ` Sean Christopherson
2022-02-04 11:57 ` [PATCH 05/23] KVM: MMU: pull computation of kvm_mmu_role_regs to kvm_init_mmu Paolo Bonzini
2022-02-04 18:45 ` David Matlack
2022-02-04 11:57 ` [PATCH 06/23] KVM: MMU: load new PGD once nested two-dimensional paging is initialized Paolo Bonzini
2022-02-04 19:18 ` David Matlack
2022-02-07 13:50 ` Paolo Bonzini
2022-02-07 14:35 ` Paolo Bonzini
2022-02-09 12:34 ` Paolo Bonzini
2022-02-04 11:57 ` [PATCH 07/23] KVM: MMU: remove kvm_mmu_calc_root_page_role Paolo Bonzini
2022-02-04 19:32 ` David Matlack
2022-02-05 14:46 ` Paolo Bonzini
2022-02-10 0:47 ` Sean Christopherson
2022-02-10 9:52 ` Paolo Bonzini
2022-02-10 17:29 ` Sean Christopherson
2022-02-10 17:43 ` Paolo Bonzini [this message]
2022-02-04 11:57 ` [PATCH 08/23] KVM: MMU: rephrase unclear comment Paolo Bonzini
2022-02-04 19:38 ` David Matlack
2022-02-04 11:57 ` [PATCH 09/23] KVM: MMU: remove "bool base_only" arguments Paolo Bonzini
2022-02-04 19:41 ` David Matlack
2022-02-04 11:57 ` [PATCH 10/23] KVM: MMU: split cpu_role from mmu_role Paolo Bonzini
2022-02-04 21:57 ` David Matlack
2022-02-05 14:49 ` Paolo Bonzini
2022-02-07 21:38 ` David Matlack
2022-02-04 11:57 ` [PATCH 11/23] KVM: MMU: do not recompute root level from kvm_mmu_role_regs Paolo Bonzini
2022-02-07 22:10 ` David Matlack
2022-02-07 22:17 ` David Matlack
2022-02-04 11:57 ` [PATCH 12/23] KVM: MMU: remove ept_ad field Paolo Bonzini
2022-02-04 11:57 ` [PATCH 13/23] KVM: MMU: remove kvm_calc_shadow_root_page_role_common Paolo Bonzini
2022-02-07 22:25 ` David Matlack
2022-02-04 11:57 ` [PATCH 14/23] KVM: MMU: cleanup computation of MMU roles for two-dimensional paging Paolo Bonzini
2022-02-04 11:57 ` [PATCH 15/23] KVM: MMU: cleanup computation of MMU roles for shadow paging Paolo Bonzini
2022-02-04 11:57 ` [PATCH 16/23] KVM: MMU: remove extended bits from mmu_role Paolo Bonzini
2022-02-04 11:57 ` [PATCH 17/23] KVM: MMU: remove redundant bits from extended role Paolo Bonzini
2022-02-04 11:57 ` [PATCH 18/23] KVM: MMU: fetch shadow EFER.NX from MMU role Paolo Bonzini
2022-02-04 11:57 ` [PATCH 19/23] KVM: MMU: simplify and/or inline computation of shadow MMU roles Paolo Bonzini
2022-02-04 11:57 ` [PATCH 20/23] KVM: MMU: pull CPU role computation to kvm_init_mmu Paolo Bonzini
2022-02-07 22:42 ` David Matlack
2022-02-04 11:57 ` [PATCH 21/23] KVM: MMU: store shadow_root_level into mmu_role Paolo Bonzini
2022-02-07 23:00 ` David Matlack
2022-02-04 11:57 ` [PATCH 22/23] KVM: MMU: use cpu_role for root_level Paolo Bonzini
2022-02-07 23:01 ` David Matlack
2022-02-04 11:57 ` [PATCH 23/23] KVM: MMU: replace direct_map with mmu_role.direct Paolo Bonzini
2022-02-07 23:02 ` David Matlack
2022-02-07 23:08 ` [PATCH 00/23] KVM: MMU: MMU role refactoring David Matlack
2022-02-07 23:27 ` Sean Christopherson
2022-02-07 23:53 ` David Matlack
2022-02-10 1:11 ` Sean Christopherson
2022-02-10 11:58 ` Paolo Bonzini
2022-02-10 16:55 ` Sean Christopherson
2022-02-10 17:30 ` Paolo Bonzini
2022-02-10 19:28 ` Sean Christopherson
2022-02-09 22:31 ` Sean Christopherson
2022-02-10 9:54 ` Paolo Bonzini
2022-02-14 18:14 ` David Matlack
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