linux-kernel - [PATCH 32/54] KVM: x86/mmu: Use MMU's role to compute permission bitmask

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Message-Id: <20210622175739.3610207-33-seanjc@google.com>
Date:   Tue, 22 Jun 2021 10:57:17 -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 32/54] KVM: x86/mmu: Use MMU's role to compute permission bitmask

Use the MMU's role to generate the permission bitmasks for the MMU.
For some flows, the vCPU state may not be correct (or relevant), e.g.
the nested NPT MMU can be initialized with incoherent vCPU state.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/mmu/mmu.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index c3bf5d4186e9..bd412e082356 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4365,8 +4365,7 @@ reset_ept_shadow_zero_bits_mask(struct kvm_vcpu *vcpu,
 	 (7 & (access) ? 128 : 0))
 
 
-static void update_permission_bitmask(struct kvm_vcpu *vcpu,
-				      struct kvm_mmu *mmu, bool ept)
+static void update_permission_bitmask(struct kvm_mmu *mmu, bool ept)
 {
 	unsigned byte;
 
@@ -4374,9 +4373,9 @@ static void update_permission_bitmask(struct kvm_vcpu *vcpu,
 	const u8 w = BYTE_MASK(ACC_WRITE_MASK);
 	const u8 u = BYTE_MASK(ACC_USER_MASK);
 
-	bool cr4_smep = kvm_read_cr4_bits(vcpu, X86_CR4_SMEP) != 0;
-	bool cr4_smap = kvm_read_cr4_bits(vcpu, X86_CR4_SMAP) != 0;
-	bool cr0_wp = is_write_protection(vcpu);
+	bool cr4_smep = is_cr4_smep(mmu);
+	bool cr4_smap = is_cr4_smap(mmu);
+	bool cr0_wp = is_cr0_wp(mmu);
 
 	for (byte = 0; byte < ARRAY_SIZE(mmu->permissions); ++byte) {
 		unsigned pfec = byte << 1;
@@ -4672,7 +4671,7 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
 		context->gva_to_gpa = paging32_gva_to_gpa;
 	}
 
-	update_permission_bitmask(vcpu, context, false);
+	update_permission_bitmask(context, false);
 	update_pkru_bitmask(vcpu, context, false);
 	update_last_nonleaf_level(vcpu, context);
 	reset_tdp_shadow_zero_bits_mask(vcpu, context);
@@ -4730,7 +4729,7 @@ static void shadow_mmu_init_context(struct kvm_vcpu *vcpu, struct kvm_mmu *conte
 
 	if (____is_cr0_pg(regs)) {
 		reset_rsvds_bits_mask(vcpu, context);
-		update_permission_bitmask(vcpu, context, false);
+		update_permission_bitmask(context, false);
 		update_pkru_bitmask(vcpu, context, false);
 		update_last_nonleaf_level(vcpu, context);
 	}
@@ -4838,7 +4837,7 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
 	context->root_level = level;
 	context->direct_map = false;
 
-	update_permission_bitmask(vcpu, context, true);
+	update_permission_bitmask(context, true);
 	update_pkru_bitmask(vcpu, context, true);
 	update_last_nonleaf_level(vcpu, context);
 	reset_rsvds_bits_mask_ept(vcpu, context, execonly);
@@ -4935,7 +4934,7 @@ static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
 		g_context->gva_to_gpa = paging32_gva_to_gpa_nested;
 	}
 
-	update_permission_bitmask(vcpu, g_context, false);
+	update_permission_bitmask(g_context, false);
 	update_pkru_bitmask(vcpu, g_context, false);
 	update_last_nonleaf_level(vcpu, g_context);
 }
-- 
2.32.0.288.g62a8d224e6-goog