From: Sean Christopherson <seanjc@google.com>
To: Rick P Edgecombe <rick.p.edgecombe@intel.com>
Cc: Kai Huang <kai.huang@intel.com>,
"ackerleytng@google.com" <ackerleytng@google.com>,
Vishal Annapurve <vannapurve@google.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Yan Y Zhao <yan.y.zhao@intel.com>,
Ira Weiny <ira.weiny@intel.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"michael.roth@amd.com" <michael.roth@amd.com>
Subject: Re: [RFC PATCH v2 05/18] KVM: TDX: Drop superfluous page pinning in S-EPT management
Date: Fri, 29 Aug 2025 15:02:34 -0700 [thread overview]
Message-ID: <aLIjelexDYa5dtkn@google.com> (raw)
In-Reply-To: <e3b1daca29f5a50bd1d01df1aa1a0403f36d596b.camel@intel.com>
On Fri, Aug 29, 2025, Rick P Edgecombe wrote:
> On Fri, 2025-08-29 at 13:19 -0700, Sean Christopherson wrote:
> > I'm happy to include more context in the changelog, but I really don't want
> > anyone to walk away from this thinking that pinning pages in random KVM code
> > is at all encouraged.
>
> Sorry for going on a tangent. Defensive programming inside the kernel is a
> little more settled. But for defensive programming against the TDX module, there
> are various schools of thought internally. Currently we rely on some
> undocumented behavior of the TDX module (as in not in the spec) for correctness.
Examples?
> But I don't think we do for security.
>
> Speaking for Yan here, I think she was a little more worried about this scenario
> then me, so I read this verbiage and thought to try to close it out.
next prev parent reply other threads:[~2025-08-29 22:02 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-29 0:06 [RFC PATCH v2 00/18] KVM: x86/mmu: TDX post-populate cleanups Sean Christopherson
2025-08-29 0:06 ` [RFC PATCH v2 01/18] KVM: TDX: Drop PROVE_MMU=y sanity check on to-be-populated mappings Sean Christopherson
2025-08-29 6:20 ` Binbin Wu
2025-08-29 0:06 ` [RFC PATCH v2 02/18] KVM: x86/mmu: Add dedicated API to map guest_memfd pfn into TDP MMU Sean Christopherson
2025-08-29 18:34 ` Edgecombe, Rick P
2025-08-29 20:27 ` Sean Christopherson
2025-08-29 0:06 ` [RFC PATCH v2 03/18] Revert "KVM: x86/tdp_mmu: Add a helper function to walk down the TDP MMU" Sean Christopherson
2025-08-29 19:00 ` Edgecombe, Rick P
2025-08-29 0:06 ` [RFC PATCH v2 04/18] KVM: x86/mmu: Rename kvm_tdp_map_page() to kvm_tdp_page_prefault() Sean Christopherson
2025-08-29 19:03 ` Edgecombe, Rick P
2025-08-29 0:06 ` [RFC PATCH v2 05/18] KVM: TDX: Drop superfluous page pinning in S-EPT management Sean Christopherson
2025-08-29 8:36 ` Binbin Wu
2025-08-29 19:53 ` Edgecombe, Rick P
2025-08-29 20:19 ` Sean Christopherson
2025-08-29 21:54 ` Edgecombe, Rick P
2025-08-29 22:02 ` Sean Christopherson [this message]
2025-08-29 22:17 ` Edgecombe, Rick P
2025-08-29 22:58 ` Sean Christopherson
2025-08-29 22:59 ` Edgecombe, Rick P
2025-09-01 1:25 ` Yan Zhao
2025-09-02 17:33 ` Sean Christopherson
2025-09-02 18:55 ` Edgecombe, Rick P
2025-09-04 8:45 ` Sean Christopherson
2025-08-29 0:06 ` [RFC PATCH v2 06/18] KVM: TDX: Return -EIO, not -EINVAL, on a KVM_BUG_ON() condition Sean Christopherson
2025-08-29 9:40 ` Binbin Wu
2025-08-29 16:58 ` Ira Weiny
2025-08-29 19:59 ` Edgecombe, Rick P
2025-08-29 0:06 ` [RFC PATCH v2 07/18] KVM: TDX: Fold tdx_sept_drop_private_spte() into tdx_sept_remove_private_spte() Sean Christopherson
2025-08-29 9:49 ` Binbin Wu
2025-08-29 0:06 ` [RFC PATCH v2 08/18] KVM: x86/mmu: Drop the return code from kvm_x86_ops.remove_external_spte() Sean Christopherson
2025-08-29 9:52 ` Binbin Wu
2025-08-29 0:06 ` [RFC PATCH v2 09/18] KVM: TDX: Avoid a double-KVM_BUG_ON() in tdx_sept_zap_private_spte() Sean Christopherson
2025-08-29 9:52 ` Binbin Wu
2025-08-29 0:06 ` [RFC PATCH v2 10/18] KVM: TDX: Use atomic64_dec_return() instead of a poor equivalent Sean Christopherson
2025-08-29 10:06 ` Binbin Wu
2025-08-29 0:06 ` [RFC PATCH v2 11/18] KVM: TDX: Fold tdx_mem_page_record_premap_cnt() into its sole caller Sean Christopherson
2025-09-02 22:46 ` Edgecombe, Rick P
2025-08-29 0:06 ` [RFC PATCH v2 12/18] KVM: TDX: Bug the VM if extended the initial measurement fails Sean Christopherson
2025-08-29 8:18 ` Yan Zhao
2025-08-29 18:16 ` Edgecombe, Rick P
2025-08-29 20:11 ` Sean Christopherson
2025-08-29 22:39 ` Edgecombe, Rick P
2025-08-29 23:15 ` Edgecombe, Rick P
2025-08-29 23:18 ` Sean Christopherson
2025-09-02 9:24 ` Yan Zhao
2025-09-02 17:04 ` Sean Christopherson
2025-09-03 0:18 ` Edgecombe, Rick P
2025-09-03 3:34 ` Yan Zhao
2025-09-03 9:19 ` Yan Zhao
2025-08-29 0:06 ` [RFC PATCH v2 13/18] KVM: TDX: ADD pages to the TD image while populating mirror EPT entries Sean Christopherson
2025-08-29 23:42 ` Edgecombe, Rick P
2025-09-02 17:09 ` Sean Christopherson
2025-08-29 0:06 ` [RFC PATCH v2 14/18] KVM: TDX: Fold tdx_sept_zap_private_spte() into tdx_sept_remove_private_spte() Sean Christopherson
2025-09-02 17:31 ` Edgecombe, Rick P
2025-08-29 0:06 ` [RFC PATCH v2 15/18] KVM: TDX: Combine KVM_BUG_ON + pr_tdx_error() into TDX_BUG_ON() Sean Christopherson
2025-08-29 9:03 ` Binbin Wu
2025-08-29 14:19 ` Sean Christopherson
2025-09-01 1:46 ` Binbin Wu
2025-09-02 18:55 ` Edgecombe, Rick P
2025-08-29 0:06 ` [RFC PATCH v2 16/18] KVM: TDX: Derive error argument names from the local variable names Sean Christopherson
2025-08-30 0:00 ` Edgecombe, Rick P
2025-08-29 0:06 ` [RFC PATCH v2 17/18] KVM: TDX: Assert that mmu_lock is held for write when removing S-EPT entries Sean Christopherson
2025-08-29 0:06 ` [RFC PATCH v2 18/18] KVM: TDX: Add macro to retry SEAMCALLs when forcing vCPUs out of guest Sean Christopherson
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