From: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
To: "pbonzini@redhat.com" <pbonzini@redhat.com>,
"Hansen, Dave" <dave.hansen@intel.com>,
"seanjc@google.com" <seanjc@google.com>,
"Zhao, Yan Y" <yan.y.zhao@intel.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"Du, Fan" <fan.du@intel.com>,
"Li, Xiaoyao" <xiaoyao.li@intel.com>,
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Subject: Re: [PATCH v4 06/17] KVM: x86/mmu: Allocate DPAMT pages for vCPU-induced page split
Date: Wed, 7 Oct 2026 15:45:48 +0000 [thread overview]
Message-ID: <76157e3dcff065d444d83a9c5e7a924967fecc87.camel@intel.com> (raw)
In-Reply-To: <20260928091005.15567-1-yan.y.zhao@intel.com>
On Mon, 2026-09-28 at 17:10 +0800, Yan Zhao wrote:
> From: Sean Christopherson <seanjc@google.com>
>
> Extend the TDP MMU to allocate Dynamic PAMT backing pages (DPAMT pages) for
> vCPU-induced huge page splits in mirror roots when DPAMT is enabled.
>
> Leverage the .topup_external_cache() interface to topup the DPAMT cache
> when allocating a new child page table for splitting. The DPAMT cache is
> currently a per-vCPU thread-local list. When a vCPU-induced page split
> occurs, DPAMT pages can be drawn locklessly from the list.
>
> Pass min_nr_spts as 1 to .topup_external_cache(), indicating there's one
> new S-EPT page table page. So, tdx_topup_external_pamt_cache() will
> allocate DPAMT page pairs for both the newly added S-EPT page table page
> and the demoted guest private page.
>
> tdp_mmu_alloc_sp_for_split() is currently not reachable from a non-vCPU
> context for mirror roots, since dirty page tracking is not yet allowed on
> mirror roots. So, simply add a WARN if tdx_topup_external_pamt_cache() is
> invoked under a non-vCPU context.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
> ---
> v4: new patch.
New? It is essentially this with a new log, right?
https://lore.kernel.org/kvm/20260129011517.3545883-39-seanjc@google.com/#t
Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
next prev parent reply other threads:[~2026-10-07 15:46 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-28 9:07 [PATCH v4 00/17] KVM: TDX huge page support for private memory Yan Zhao
2026-09-28 9:08 ` [PATCH v4 01/17] x86/virt/tdx: Enhance tdx_pamt_get/put() to support huge pages Yan Zhao
2026-10-01 23:02 ` Edgecombe, Rick P
2026-09-28 9:08 ` [PATCH v4 02/17] x86/virt/tdx: Add a SEAMCALL wrapper to demote a 2MB huge page Yan Zhao
2026-10-02 0:54 ` Edgecombe, Rick P
2026-09-28 9:08 ` [PATCH v4 03/17] KVM: TDX: Reset private huge pages after S-EPT page removal Yan Zhao
2026-10-07 0:06 ` Edgecombe, Rick P
2026-09-28 9:09 ` [PATCH v4 04/17] KVM: x86/mmu: Prevent huge page promotion for mirror roots in fault path Yan Zhao
2026-10-07 0:32 ` Edgecombe, Rick P
2026-09-28 9:09 ` [PATCH v4 05/17] KVM: x86/tdp_mmu: Alloc external_spt page for mirror page table splitting Yan Zhao
2026-10-07 0:33 ` Edgecombe, Rick P
2026-09-28 9:10 ` [PATCH v4 06/17] KVM: x86/mmu: Allocate DPAMT pages for vCPU-induced page split Yan Zhao
2026-10-07 15:45 ` Edgecombe, Rick P [this message]
2026-09-28 9:10 ` [PATCH v4 07/17] KVM: TDX: Add core support for splitting/demoting 2MB S-EPT mappings to 4KB Yan Zhao
2026-09-28 9:10 ` [PATCH v4 08/17] KVM: TDX: Adjust the topup count of DPAMT page pairs for splitting S-EPT Yan Zhao
2026-09-28 9:10 ` [PATCH v4 09/17] KVM: x86/mmu: Introduce hugepage_set_guest_inhibit() Yan Zhao
2026-09-28 9:11 ` [PATCH v4 10/17] KVM: x86/mmu: Add a TDP MMU API to split huge pages for mirror roots Yan Zhao
2026-09-28 9:11 ` [PATCH v4 11/17] KVM: TDX: Honor the guest's accept level contained in an EPT violation Yan Zhao
2026-09-28 9:11 ` [PATCH v4 12/17] KVM: x86/mmu: Add support for splitting S-EPT entry under non-vCPU context Yan Zhao
2026-09-28 9:11 ` [PATCH v4 13/17] [GMEM-DEPENDENT] KVM: guest_memfd: Add helpers to get start/end gfns give gmem+slot+pgoff Yan Zhao
2026-09-28 9:11 ` [PATCH v4 14/17] [GMEM-DEPENDENT] KVM: guest_memfd: Split kvm_gmem_invalidate_start() to start() and zap() Yan Zhao
2026-09-28 9:12 ` [PATCH v4 15/17] [GMEM-DEPENDENT] KVM: guest_memfd: Add a pre-zap hook .gmem_prezap() Yan Zhao
2026-09-28 9:12 ` [PATCH v4 16/17] [GMEM-DEPENDENT] KVM: TDX: Implement .gmem_prezap() hook to split S-EPT Yan Zhao
2026-09-28 9:12 ` [PATCH v4 17/17] KVM: TDX: Turn on PG_LEVEL_2M Yan Zhao
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