linux-kernel - [RFC PATCH 02/13] KVM: TDP_MMU: Go to next level if smaller private mapping exists

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Date:   Sun,  7 Aug 2022 15:18:35 -0700
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>, erdemaktas@...gle.com,
        Sean Christopherson <seanjc@...gle.com>,
        Sagi Shahar <sagis@...gle.com>
Subject: [RFC PATCH 02/13] KVM: TDP_MMU: Go to next level if smaller private mapping exists

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

Cannot map a private page as large page if any smaller mapping exists.

It has to wait for all the not-mapped smaller page to be mapped and
promote it to larger mapping.

Signed-off-by: Xiaoyao Li <xiaoyao.li@...el.com>
---
 arch/x86/kvm/mmu/tdp_mmu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index f2461deba2dc..faf278e0c740 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -1322,7 +1322,8 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
 	}
 
 	tdp_mmu_for_each_pte(iter, mmu, is_private, raw_gfn, raw_gfn + 1) {
-		if (fault->nx_huge_page_workaround_enabled)
+		if (fault->nx_huge_page_workaround_enabled ||
+		    kvm_gfn_shared_mask(vcpu->kvm))
 			disallowed_hugepage_adjust(fault, iter.old_spte, iter.level);
 
 		if (iter.level == fault->goal_level)
-- 
2.25.1