linux-kernel - [PATCH 39/54] KVM: x86/mmu: Get nested MMU's root level from the MMU's role

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Message-Id: <20210622175739.3610207-40-seanjc@google.com>
Date:   Tue, 22 Jun 2021 10:57:24 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Yu Zhang <yu.c.zhang@...ux.intel.com>,
        Maxim Levitsky <mlevitsk@...hat.com>
Subject: [PATCH 39/54] KVM: x86/mmu: Get nested MMU's root level from the
 MMU's role

Initialize the MMU's (guest) root_level using its mmu_role instead of
redoing the calculations.  The role_regs used to calculate the mmu_role
are initialized from the vCPU, i.e. this should be a complete nop.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/mmu/mmu.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 6c4655c356b7..6418b50d33ca 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4874,6 +4874,7 @@ static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
 	g_context->get_guest_pgd     = get_cr3;
 	g_context->get_pdptr         = kvm_pdptr_read;
 	g_context->inject_page_fault = kvm_inject_page_fault;
+	g_context->root_level        = new_role.base.level;
 
 	/*
 	 * L2 page tables are never shadowed, so there is no need to sync
@@ -4890,19 +4891,14 @@ static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
 	 * the gva_to_gpa functions between mmu and nested_mmu are swapped.
 	 */
 	if (!is_paging(vcpu)) {
-		g_context->root_level = 0;
 		g_context->gva_to_gpa = nonpaging_gva_to_gpa_nested;
 	} else if (is_long_mode(vcpu)) {
-		g_context->root_level = is_la57_mode(vcpu) ?
-					PT64_ROOT_5LEVEL : PT64_ROOT_4LEVEL;
 		reset_rsvds_bits_mask(vcpu, g_context);
 		g_context->gva_to_gpa = paging64_gva_to_gpa_nested;
 	} else if (is_pae(vcpu)) {
-		g_context->root_level = PT32E_ROOT_LEVEL;
 		reset_rsvds_bits_mask(vcpu, g_context);
 		g_context->gva_to_gpa = paging64_gva_to_gpa_nested;
 	} else {
-		g_context->root_level = PT32_ROOT_LEVEL;
 		reset_rsvds_bits_mask(vcpu, g_context);
 		g_context->gva_to_gpa = paging32_gva_to_gpa_nested;
 	}
-- 
2.32.0.288.g62a8d224e6-goog