From: Sean Christopherson <seanjc@google.com>
To: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: yan.y.zhao@intel.com, dmatlack@google.com, erdemaktas@google.com,
isaku.yamahata@intel.com, kai.huang@intel.com,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
pbonzini@redhat.com, sagis@google.com
Subject: Re: [PATCH] KVM: x86/mmu: Implement memslot deletion for TDX
Date: Thu, 20 Jun 2024 17:08:37 -0700 [thread overview]
Message-ID: <ZnTEhQo2r3Uz9rDY@google.com> (raw)
In-Reply-To: <20240620193701.374519-1-rick.p.edgecombe@intel.com>
On Thu, Jun 20, 2024, Rick Edgecombe wrote:
> Force TDX VMs to use the KVM_X86_QUIRK_SLOT_ZAP_ALL behavior.
>
> TDs cannot use the fast zapping operation to implement memslot deletion for
> a couple reasons:
> 1. KVM cannot zap TDX private PTEs and re-fault them without coordinating
Uber nit, this isn't strictly true, for KVM's definition of "zap" (which is fuzzy
and overloaded). KVM _could_ zap and re-fault *leaf* PTEs, e.g. BLOCK+UNBLOCK.
It's specifically the full teardown and rebuild of the "fast zap" that doesn't
play nice, as the non-leaf S-EPT entries *must* be preserved due to how the TDX
module does is refcounting.
next prev parent reply other threads:[~2024-06-21 0:08 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-13 6:06 [PATCH 0/5] Introduce a quirk to control memslot zap behavior Yan Zhao
2024-06-13 6:09 ` [PATCH 1/5] KVM: x86/mmu: " Yan Zhao
2024-06-13 6:10 ` [PATCH 2/5] KVM: selftests: Test slot move/delete with slot zap quirk enabled/disabled Yan Zhao
2024-06-13 6:10 ` [PATCH 3/5] KVM: selftests: Allow slot modification stress test with quirk disabled Yan Zhao
2024-06-13 6:10 ` [PATCH 4/5] KVM: selftests: Test memslot move in memslot_perf_test " Yan Zhao
2024-06-13 6:11 ` [PATCH 5/5] KVM: selftests: Test private access to deleted memslot " Yan Zhao
2024-06-13 20:01 ` [PATCH 0/5] Introduce a quirk to control memslot zap behavior Edgecombe, Rick P
2024-06-17 10:15 ` Yan Zhao
2024-06-18 14:34 ` Sean Christopherson
2024-06-20 3:59 ` Yan Zhao
2024-06-20 19:38 ` Edgecombe, Rick P
2024-06-21 0:00 ` Sean Christopherson
2024-06-21 1:06 ` Edgecombe, Rick P
2024-06-20 19:37 ` [PATCH] KVM: x86/mmu: Implement memslot deletion for TDX Rick Edgecombe
2024-06-20 19:40 ` Edgecombe, Rick P
2024-06-21 0:08 ` Sean Christopherson [this message]
2024-06-21 1:17 ` Edgecombe, Rick P
2024-06-21 2:14 ` Yan Zhao
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