From: "Huang, Kai" <kai.huang@intel.com>
To: "pbonzini@redhat.com" <pbonzini@redhat.com>, "Christopherson,,
Sean" <seanjc@google.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"dmatlack@google.com" <dmatlack@google.com>,
"Yamahata, Isaku" <isaku.yamahata@intel.com>
Subject: Re: [PATCH v4 01/11] KVM: x86/mmu: Change tdp_mmu to a read-only parameter
Date: Wed, 12 Oct 2022 21:37:54 +0000 [thread overview]
Message-ID: <0dead0fb06a604593cc686ebd298a6f6493afe83.camel@intel.com> (raw)
In-Reply-To: <20221012181702.3663607-2-seanjc@google.com>
On Wed, 2022-10-12 at 18:16 +0000, Sean Christopherson wrote:
> From: David Matlack <dmatlack@google.com>
>
> Change tdp_mmu to a read-only parameter and drop the per-vm
> tdp_mmu_enabled. Keep the is_tdp_mmu_enabled() helper instead of
> referencing tdp_mmu_enabled directly to allow for future optimizations
> without needing to churn a lot of code, e.g. KVM can use a static key
> for now that the knob is read-only after the vendor module is loaded.
>
> The TDP MMU was introduced in 5.10 and has been enabled by default since
> 5.15. At this point there are no known functionality gaps between the
> TDP MMU and the shadow MMU, and the TDP MMU uses less memory and scales
> better with the number of vCPUs. In other words, there is no good reason
> to disable the TDP MMU on a live system.
>
> Purposely do not drop tdp_mmu=N support (i.e. do not force 64-bit KVM to
> always use the TDP MMU) since tdp_mmu=N is still used to get test
> coverage of KVM's shadow MMU TDP support, which is used in 32-bit KVM.
>
> Signed-off-by: David Matlack <dmatlack@google.com>
> [sean: keep is_tdp_mmu_enabled()]
> Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
next prev parent reply other threads:[~2022-10-12 21:38 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-12 18:16 [PATCH v4 00/11] KVM: x86/mmu: Make tdp_mmu a read-only parameter Sean Christopherson
2022-10-12 18:16 ` [PATCH v4 01/11] KVM: x86/mmu: Change tdp_mmu to " Sean Christopherson
2022-10-12 21:37 ` Huang, Kai [this message]
2022-10-12 18:16 ` [PATCH v4 02/11] KVM: x86/mmu: Move TDP MMU VM init/uninit behind tdp_mmu_enabled Sean Christopherson
2022-10-12 18:16 ` [PATCH v4 03/11] KVM: x86/mmu: Grab mmu_invalidate_seq in kvm_faultin_pfn() Sean Christopherson
2022-10-12 18:16 ` [PATCH v4 04/11] KVM: x86/mmu: Handle error PFNs " Sean Christopherson
2022-10-12 18:16 ` [PATCH v4 05/11] KVM: x86/mmu: Avoid memslot lookup during KVM_PFN_ERR_HWPOISON handling Sean Christopherson
2022-10-12 18:16 ` [PATCH v4 06/11] KVM: x86/mmu: Handle no-slot faults in kvm_faultin_pfn() Sean Christopherson
2022-10-12 18:16 ` [PATCH v4 07/11] KVM: x86/mmu: Pivot on "TDP MMU enabled" when handling direct page faults Sean Christopherson
2022-10-12 18:16 ` [PATCH v4 08/11] KVM: x86/mmu: Pivot on "TDP MMU enabled" to check if active MMU is TDP MMU Sean Christopherson
2022-10-12 18:17 ` [PATCH v4 09/11] KVM: x86/mmu: Replace open coded usage of tdp_mmu_page with is_tdp_mmu_page() Sean Christopherson
2022-10-12 18:17 ` [PATCH v4 10/11] KVM: x86/mmu: Use static key/branches for checking if TDP MMU is enabled Sean Christopherson
2022-10-12 18:17 ` [PATCH v4 11/11] KVM: x86/mmu: Stop needlessly making MMU pages available for TDP MMU Sean Christopherson
2022-10-13 17:21 ` [PATCH v4 00/11] KVM: x86/mmu: Make tdp_mmu a read-only parameter David Matlack
2022-10-13 20:12 ` Sean Christopherson
2022-10-13 22:56 ` David Matlack
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=0dead0fb06a604593cc686ebd298a6f6493afe83.camel@intel.com \
--to=kai.huang@intel.com \
--cc=dmatlack@google.com \
--cc=isaku.yamahata@intel.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=seanjc@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox