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From: Sean Christopherson <seanjc@google.com>
To: Wei Huang <wei.huang2@amd.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	pbonzini@redhat.com, vkuznets@redhat.com, wanpengli@tencent.com,
	jmattson@google.com, joro@8bytes.org, tglx@linutronix.de,
	mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com
Subject: Re: [PATCH v3 2/3] KVM: x86: Handle the case of 5-level shadow page table
Date: Wed, 18 Aug 2021 17:15:09 +0000	[thread overview]
Message-ID: <YR1AHVwUM8AS5JvQ@google.com> (raw)
In-Reply-To: <20210818165549.3771014-3-wei.huang2@amd.com>

The shortlog is very misleading.  KVM already supports 5-level paging for
traditional shadow paging.  This is specifically for shadowing nNPT, and it's
specifically for shadow everything _except_ 5-level nNPT.  Something like:

KVM: x86/mmu: Support shadowing nNPT when 5-level paging is enabled in host


On Wed, Aug 18, 2021, Wei Huang wrote:
> When the 5-level page table CPU flag is exposed, KVM code needs to handle
> this case by pointing mmu->root_hpa to a properly-constructed 5-level page
> table.

Similarly, this is wrong, or maybe just poorly worded.  This has nothing to do
with LA57 being exposed to the guest, it's purely the host using 5-level paging
and NPT being enabled and exposed to L1.

  reply	other threads:[~2021-08-18 17:15 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-18 16:55 [PATCH v3 0/3] SVM 5-level page table support Wei Huang
2021-08-18 16:55 ` [PATCH v3 1/3] KVM: x86: Allow CPU to force vendor-specific TDP level Wei Huang
2021-08-18 16:55 ` [PATCH v3 2/3] KVM: x86: Handle the case of 5-level shadow page table Wei Huang
2021-08-18 17:15   ` Sean Christopherson [this message]
2021-08-19 16:36     ` Paolo Bonzini
2021-08-18 18:00   ` Tom Lendacky
2021-08-18 16:55 ` [PATCH v3 3/3] KVM: SVM: Add 5-level page table support for SVM Wei Huang
2021-08-18 17:32   ` Sean Christopherson
2021-08-19 16:38     ` Paolo Bonzini
2021-08-19 16:43 ` [PATCH v3 0/3] SVM 5-level page table support Paolo Bonzini
2021-08-23  9:20   ` Maxim Levitsky
2021-08-23 15:15     ` Wei Huang
2021-08-23 16:10       ` Sean Christopherson
2021-08-23 18:10         ` Maxim Levitsky
2021-08-23 18:06       ` Maxim Levitsky

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