KVM, pkeys: add pkeys support for permission_fault

Protection keys define a new 4-bit protection key field (PKEY) in bits
62:59 of leaf entries of the page tables, the PKEY is an index to PKRU
register(16 domains), every domain has 2 bits(write disable bit, access
disable bit).

Static logic has been produced in update_pkru_bitmask, dynamic logic need
read pkey from page table entries, get pkru value, and deduce the correct
result.

[ Huaitong: Xiao helps to modify many sections. ]

Signed-off-by: Huaitong Han <huaitong.han@intel.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 28 insertions, 5 deletions

diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 8b2b3dfca1ae..b70df72e2b33 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -10,10 +10,11 @@
 #define PT32_ENT_PER_PAGE (1 << PT32_PT_BITS)
 
 #define PT_WRITABLE_SHIFT 1
+#define PT_USER_SHIFT 2
 
 #define PT_PRESENT_MASK (1ULL << 0)
 #define PT_WRITABLE_MASK (1ULL << PT_WRITABLE_SHIFT)
-#define PT_USER_MASK (1ULL << 2)
+#define PT_USER_MASK (1ULL << PT_USER_SHIFT)
 #define PT_PWT_MASK (1ULL << 3)
 #define PT_PCD_MASK (1ULL << 4)
 #define PT_ACCESSED_SHIFT 5
@@ -149,7 +150,8 @@ static inline bool is_write_protection(struct kvm_vcpu *vcpu)
  * if the access faults.
  */
 static inline u8 permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
-				  unsigned pte_access, unsigned pfec)
+				  unsigned pte_access, unsigned pte_pkey,
+				  unsigned pfec)
 {
 	int cpl = kvm_x86_ops->get_cpl(vcpu);
 	unsigned long rflags = kvm_x86_ops->get_rflags(vcpu);
@@ -170,11 +172,32 @@ static inline u8 permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
 	unsigned long smap = (cpl - 3) & (rflags & X86_EFLAGS_AC);
 	int index = (pfec >> 1) +
 		    (smap >> (X86_EFLAGS_AC_BIT - PFERR_RSVD_BIT + 1));
+	bool fault = (mmu->permissions[index] >> pte_access) & 1;
 
-	WARN_ON(pfec & PFERR_RSVD_MASK);
-
+	WARN_ON(pfec & (PFERR_PK_MASK | PFERR_RSVD_MASK));
 	pfec |= PFERR_PRESENT_MASK;
-	return -((mmu->permissions[index] >> pte_access) & 1) & pfec;
+
+	if (unlikely(mmu->pkru_mask)) {
+		u32 pkru_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.
+		*/
+		pkru_bits = (kvm_read_pkru(vcpu) >> (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));
+
+		pkru_bits &= mmu->pkru_mask >> offset;
+		pfec |= -pkru_bits & PFERR_PK_MASK;
+		fault |= (pkru_bits != 0);
+	}
+
+	return -(uint32_t)fault & pfec;
 }
 
 void kvm_mmu_invalidate_zap_all_pages(struct kvm *kvm);