linux-kernel - [PATCH 03/21] KVM: x86/mmu: Do not enable page track for TD guest

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Message-Id: <20240904030751.117579-4-rick.p.edgecombe@intel.com>
Date: Tue,  3 Sep 2024 20:07:33 -0700
From: Rick Edgecombe <rick.p.edgecombe@...el.com>
To: seanjc@...gle.com,
	pbonzini@...hat.com,
	kvm@...r.kernel.org
Cc: kai.huang@...el.com,
	dmatlack@...gle.com,
	isaku.yamahata@...il.com,
	yan.y.zhao@...el.com,
	nik.borisov@...e.com,
	rick.p.edgecombe@...el.com,
	linux-kernel@...r.kernel.org,
	Yuan Yao <yuan.yao@...ux.intel.com>,
	Binbin Wu <binbin.wu@...ux.intel.com>
Subject: [PATCH 03/21] KVM: x86/mmu: Do not enable page track for TD guest

From: Yan Zhao <yan.y.zhao@...el.com>

TDX does not support write protection and hence page track.
Though !tdp_enabled and kvm_shadow_root_allocated(kvm) are always false
for TD guest, should also return false when external write tracking is
enabled.

Cc: Yuan Yao <yuan.yao@...ux.intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@...el.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@...el.com>
Reviewed-by: Binbin Wu <binbin.wu@...ux.intel.com>
---
v19:
- drop TDX: from the short log
- Added reviewed-by: BinBin
---
 arch/x86/kvm/mmu/page_track.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c
index 561c331fd6ec..26436113103a 100644
--- a/arch/x86/kvm/mmu/page_track.c
+++ b/arch/x86/kvm/mmu/page_track.c
@@ -35,6 +35,9 @@ static bool kvm_external_write_tracking_enabled(struct kvm *kvm)
 
 bool kvm_page_track_write_tracking_enabled(struct kvm *kvm)
 {
+	if (kvm->arch.vm_type == KVM_X86_TDX_VM)
+		return false;
+
 	return kvm_external_write_tracking_enabled(kvm) ||
 	       kvm_shadow_root_allocated(kvm) || !tdp_enabled;
 }
-- 
2.34.1