linux-kernel - [RFC PATCH v2 15/15] KVM: TDX: Allow 2MB large page for TD GUEST

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Date:   Thu,  8 Dec 2022 15:35:50 -0800
From:   isaku.yamahata@...el.com
To:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     isaku.yamahata@...el.com, isaku.yamahata@...il.com,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        David Matlack <dmatlack@...gle.com>
Subject: [RFC PATCH v2 15/15] KVM: TDX: Allow 2MB large page for TD GUEST

From: Xiaoyao Li <xiaoyao.li@...el.com>

Now that everything is there to support 2MB page for TD guest.  Because TDX
module TDH.MEM.PAGE.AUG supports 4KB page and 2MB page, set struct
kvm_arch.tdp_max_page_level to 2MB page level.

Signed-off-by: Xiaoyao Li <xiaoyao.li@...el.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
---
 arch/x86/kvm/mmu/tdp_mmu.c | 9 ++-------
 arch/x86/kvm/vmx/tdx.c     | 4 ++--
 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 766795005a39..c133dda53e12 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -1592,14 +1592,9 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
 
 		sp->nx_huge_page_disallowed = fault->huge_page_disallowed;
 
-		if (is_shadow_present_pte(iter.old_spte)) {
-			/*
-			 * TODO: large page support.
-			 * Doesn't support large page for TDX now
-			 */
-			KVM_BUG_ON(is_private_sptep(iter.sptep), vcpu->kvm);
+		if (is_shadow_present_pte(iter.old_spte))
 			r = tdp_mmu_split_huge_page(kvm, &iter, sp, true);
-		} else
+		else
 			r = tdp_mmu_link_sp(kvm, &iter, sp, true);
 
 		/*
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index f20e931cf983..1977a2a5b4c4 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -481,8 +481,8 @@ int tdx_vm_init(struct kvm *kvm)
 	 */
 	kvm_mmu_set_mmio_spte_value(kvm, 0);
 
-	/* TODO: Enable 2mb and 1gb large page support. */
-	kvm->arch.tdp_max_page_level = PG_LEVEL_4K;
+	/* TDH.MEM.PAGE.AUG supports up to 2MB page. */
+	kvm->arch.tdp_max_page_level = PG_LEVEL_2M;
 
 	kvm_tdx->hkid = -1;
 
-- 
2.25.1