linux-kernel - [PATCH 05/43] KVM: x86: Split out CR0/CR4 MMU role change detectors to separate helpers

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Date:   Fri, 23 Apr 2021 17:46:07 -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
Subject: [PATCH 05/43] KVM: x86: Split out CR0/CR4 MMU role change detectors
 to separate helpers

Split out the post-CR0/CR4 MMU role change detectors to separate helpers,
they will be used during vCPU RESET/INIT to conditionally reset the MMU
in a future patch.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/x86.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3bf52ba5f2bb..0bc783fc6c9b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -823,16 +823,21 @@ bool pdptrs_changed(struct kvm_vcpu *vcpu)
 }
 EXPORT_SYMBOL_GPL(pdptrs_changed);
 
+static bool kvm_cr0_mmu_role_changed(unsigned long old_cr0, unsigned long cr0)
+{
+	unsigned long mmu_role_bits = X86_CR0_PG | X86_CR0_WP;
+
+	return (cr0 ^ old_cr0) & mmu_role_bits;
+}
+
 void kvm_post_set_cr0(struct kvm_vcpu *vcpu, unsigned long old_cr0, unsigned long cr0)
 {
-	unsigned long update_bits = X86_CR0_PG | X86_CR0_WP;
-
 	if ((cr0 ^ old_cr0) & X86_CR0_PG) {
 		kvm_clear_async_pf_completion_queue(vcpu);
 		kvm_async_pf_hash_reset(vcpu);
 	}
 
-	if ((cr0 ^ old_cr0) & update_bits)
+	if (kvm_cr0_mmu_role_changed(old_cr0, cr0))
 		kvm_mmu_reset_context(vcpu);
 
 	if (((cr0 ^ old_cr0) & X86_CR0_CD) &&
@@ -1009,13 +1014,18 @@ bool kvm_is_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 }
 EXPORT_SYMBOL_GPL(kvm_is_valid_cr4);
 
-void kvm_post_set_cr4(struct kvm_vcpu *vcpu, unsigned long old_cr4, unsigned long cr4)
+static bool kvm_cr4_mmu_role_changed(unsigned long old_cr4, unsigned long cr4)
 {
 	unsigned long mmu_role_bits = X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PAE |
 				      X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_PKE;
 
-	if (((cr4 ^ old_cr4) & mmu_role_bits) ||
-	    (!(cr4 & X86_CR4_PCIDE) && (old_cr4 & X86_CR4_PCIDE)))
+	return (((cr4 ^ old_cr4) & mmu_role_bits) ||
+	       (!(cr4 & X86_CR4_PCIDE) && (old_cr4 & X86_CR4_PCIDE)));
+}
+
+void kvm_post_set_cr4(struct kvm_vcpu *vcpu, unsigned long old_cr4, unsigned long cr4)
+{
+	if (kvm_cr4_mmu_role_changed(old_cr4, cr4))
 		kvm_mmu_reset_context(vcpu);
 }
 EXPORT_SYMBOL_GPL(kvm_post_set_cr4);
-- 
2.31.1.498.g6c1eba8ee3d-goog