linux-kernel - [PATCH v7 5/8] KVM: MMU: Add helper function to get pkr bits

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Date:   Sun, 24 Apr 2022 03:15:54 -0700
From:   Lei Wang <lei4.wang@...el.com>
To:     pbonzini@...hat.com, seanjc@...gle.com, vkuznets@...hat.com,
        wanpengli@...cent.com, jmattson@...gle.com, joro@...tes.org
Cc:     lei4.wang@...el.com, chenyi.qiang@...el.com, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v7 5/8] KVM: MMU: Add helper function to get pkr bits

Extra the PKR stuff to a separate, non-inline helper, which is a
preparation to introduce pks support.

Signed-off-by: Lei Wang <lei4.wang@...el.com>
---
 arch/x86/kvm/mmu.h     | 20 +++++---------------
 arch/x86/kvm/mmu/mmu.c | 21 +++++++++++++++++++++
 2 files changed, 26 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index cb3f07e63778..cea03053a153 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -204,6 +204,9 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
 	return vcpu->arch.mmu->page_fault(vcpu, &fault);
 }
 
+u32 kvm_mmu_pkr_bits(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
+		     unsigned pte_access, unsigned pte_pkey, unsigned int pfec);
+
 /*
  * Check if a given access (described through the I/D, W/R and U/S bits of a
  * page fault error code pfec) causes a permission fault with the given PTE
@@ -240,21 +243,8 @@ static inline u8 permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
 
 	WARN_ON(pfec & (PFERR_PK_MASK | PFERR_RSVD_MASK));
 	if (unlikely(mmu->pkr_mask)) {
-		u32 pkr_bits, offset;
-
-		/*
-		* PKRU defines 32 bits, there are 16 domains and 2
-		* attribute bits per domain in pkru.  pte_pkey is the
-		* index of the protection domain, so pte_pkey * 2 is
-		* is the index of the first bit for the domain.
-		*/
-		pkr_bits = (vcpu->arch.pkru >> (pte_pkey * 2)) & 3;
-
-		/* clear present bit, replace PFEC.RSVD with ACC_USER_MASK. */
-		offset = (pfec & ~1) +
-			((pte_access & PT_USER_MASK) << (PFERR_RSVD_BIT - PT_USER_SHIFT));
-
-		pkr_bits &= mmu->pkr_mask >> offset;
+		u32 pkr_bits =
+			kvm_mmu_pkr_bits(vcpu, mmu, pte_access, pte_pkey, pfec);
 		errcode |= -pkr_bits & PFERR_PK_MASK;
 		fault |= (pkr_bits != 0);
 	}
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index de665361548d..6d3276986102 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -6477,3 +6477,24 @@ void kvm_mmu_pre_destroy_vm(struct kvm *kvm)
 	if (kvm->arch.nx_lpage_recovery_thread)
 		kthread_stop(kvm->arch.nx_lpage_recovery_thread);
 }
+
+u32 kvm_mmu_pkr_bits(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
+		     unsigned pte_access, unsigned pte_pkey, unsigned int pfec)
+{
+	u32 pkr_bits, offset;
+
+	/*
+	* PKRU defines 32 bits, there are 16 domains and 2
+	* attribute bits per domain in pkru.  pte_pkey is the
+	* index of the protection domain, so pte_pkey * 2 is
+	* is the index of the first bit for the domain.
+	*/
+	pkr_bits = (vcpu->arch.pkru >> (pte_pkey * 2)) & 3;
+
+	/* clear present bit, replace PFEC.RSVD with ACC_USER_MASK. */
+	offset = (pfec & ~1) + ((pte_access & PT_USER_MASK)
+				<< (PFERR_RSVD_BIT - PT_USER_SHIFT));
+
+	pkr_bits &= mmu->pkr_mask >> offset;
+	return pkr_bits;
+}
-- 
2.25.1