KVM: x86: Add helpers to query individual CR0/CR4 bits

Add helpers to check if a specific CR0/CR4 bit is set to avoid a plethora
of implicit casts from the "unsigned long" return of kvm_read_cr*_bits(),
and to make each caller's intent more obvious.

Defer converting helpers that do truly ugly casts from "unsigned long" to
"int", e.g. is_pse(), to a future commit so that their conversion is more
isolated.

Opportunistically drop the superfluous pcid_enabled from kvm_set_cr3();
the local variable is used only once, immediately after its declaration.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
Link: https://lore.kernel.org/r/20230322045824.22970-2-binbin.wu@linux.intel.com
[sean: move "obvious" conversions to this commit, massage changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: Binbin Wu

arch/x86/kvm/cpuid.c

@@ -266,7 +266,7 @@ static void __kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu, struct kvm_cpuid_e
 		/* Update OSXSAVE bit */
 		if (boot_cpu_has(X86_FEATURE_XSAVE))
 			cpuid_entry_change(best, X86_FEATURE_OSXSAVE,
-				   kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE));
+					   kvm_is_cr4_bit_set(vcpu, X86_CR4_OSXSAVE));
 
 		cpuid_entry_change(best, X86_FEATURE_APIC,
 			   vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE);
@@ -275,7 +275,7 @@ static void __kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu, struct kvm_cpuid_e
 	best = cpuid_entry2_find(entries, nent, 7, 0);
 	if (best && boot_cpu_has(X86_FEATURE_PKU) && best->function == 0x7)
 		cpuid_entry_change(best, X86_FEATURE_OSPKE,
-				   kvm_read_cr4_bits(vcpu, X86_CR4_PKE));
+				   kvm_is_cr4_bit_set(vcpu, X86_CR4_PKE));
 
 	best = cpuid_entry2_find(entries, nent, 0xD, 0);
 	if (best)

arch/x86/kvm/kvm_cache_regs.h

@@ -157,6 +157,14 @@ static inline ulong kvm_read_cr0_bits(struct kvm_vcpu *vcpu, ulong mask)
 	return vcpu->arch.cr0 & mask;
 }
 
+static __always_inline bool kvm_is_cr0_bit_set(struct kvm_vcpu *vcpu,
+					       unsigned long cr0_bit)
+{
+	BUILD_BUG_ON(!is_power_of_2(cr0_bit));
+
+	return !!kvm_read_cr0_bits(vcpu, cr0_bit);
+}
+
 static inline ulong kvm_read_cr0(struct kvm_vcpu *vcpu)
 {
 	return kvm_read_cr0_bits(vcpu, ~0UL);
@@ -171,6 +179,14 @@ static inline ulong kvm_read_cr4_bits(struct kvm_vcpu *vcpu, ulong mask)
 	return vcpu->arch.cr4 & mask;
 }
 
+static __always_inline bool kvm_is_cr4_bit_set(struct kvm_vcpu *vcpu,
+					       unsigned long cr4_bit)
+{
+	BUILD_BUG_ON(!is_power_of_2(cr4_bit));
+
+	return !!kvm_read_cr4_bits(vcpu, cr4_bit);
+}
+
 static inline ulong kvm_read_cr3(struct kvm_vcpu *vcpu)
 {
 	if (!kvm_register_is_available(vcpu, VCPU_EXREG_CR3))

arch/x86/kvm/mmu.h

@@ -132,7 +132,7 @@ static inline unsigned long kvm_get_pcid(struct kvm_vcpu *vcpu, gpa_t cr3)
 {
 	BUILD_BUG_ON((X86_CR3_PCID_MASK & PAGE_MASK) != 0);
 
-	return kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE)
+	return kvm_is_cr4_bit_set(vcpu, X86_CR4_PCIDE)
 	       ? cr3 & X86_CR3_PCID_MASK
 	       : 0;
 }

arch/x86/kvm/pmu.c

@@ -540,9 +540,9 @@ int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
 	if (!pmc)
 		return 1;
 
-	if (!(kvm_read_cr4_bits(vcpu, X86_CR4_PCE)) &&
+	if (!kvm_is_cr4_bit_set(vcpu, X86_CR4_PCE) &&
 	    (static_call(kvm_x86_get_cpl)(vcpu) != 0) &&
-	    (kvm_read_cr0_bits(vcpu, X86_CR0_PE)))
+	    kvm_is_cr0_bit_set(vcpu, X86_CR0_PE))
 		return 1;
 
 	*data = pmc_read_counter(pmc) & mask;

arch/x86/kvm/vmx/nested.c

@@ -5154,7 +5154,7 @@ static int handle_vmxon(struct kvm_vcpu *vcpu)
 	 * does force CR0.PE=1, but only to also force VM86 in order to emulate
 	 * Real Mode, and so there's no need to check CR0.PE manually.
 	 */
-	if (!kvm_read_cr4_bits(vcpu, X86_CR4_VMXE)) {
+	if (!kvm_is_cr4_bit_set(vcpu, X86_CR4_VMXE)) {
 		kvm_queue_exception(vcpu, UD_VECTOR);
 		return 1;
 	}

arch/x86/kvm/vmx/vmx.c

@@ -5180,7 +5180,7 @@ bool vmx_guest_inject_ac(struct kvm_vcpu *vcpu)
 	if (!boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT))
 		return true;
 
-	return vmx_get_cpl(vcpu) == 3 && kvm_read_cr0_bits(vcpu, X86_CR0_AM) &&
+	return vmx_get_cpl(vcpu) == 3 && kvm_is_cr0_bit_set(vcpu, X86_CR0_AM) &&
 	       (kvm_get_rflags(vcpu) & X86_EFLAGS_AC);
 }
 

arch/x86/kvm/x86.c

@@ -841,7 +841,7 @@ bool kvm_require_cpl(struct kvm_vcpu *vcpu, int required_cpl)
 
 bool kvm_require_dr(struct kvm_vcpu *vcpu, int dr)
 {
-	if ((dr != 4 && dr != 5) || !kvm_read_cr4_bits(vcpu, X86_CR4_DE))
+	if ((dr != 4 && dr != 5) || !kvm_is_cr4_bit_set(vcpu, X86_CR4_DE))
 		return true;
 
 	kvm_queue_exception(vcpu, UD_VECTOR);
@@ -983,7 +983,7 @@ int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 		return 1;
 
 	if (!(cr0 & X86_CR0_PG) &&
-	    (is_64_bit_mode(vcpu) || kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE)))
+	    (is_64_bit_mode(vcpu) || kvm_is_cr4_bit_set(vcpu, X86_CR4_PCIDE)))
 		return 1;
 
 	static_call(kvm_x86_set_cr0)(vcpu, cr0);
@@ -1005,7 +1005,7 @@ void kvm_load_guest_xsave_state(struct kvm_vcpu *vcpu)
 	if (vcpu->arch.guest_state_protected)
 		return;
 
-	if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE)) {
+	if (kvm_is_cr4_bit_set(vcpu, X86_CR4_OSXSAVE)) {
 
 		if (vcpu->arch.xcr0 != host_xcr0)
 			xsetbv(XCR_XFEATURE_ENABLED_MASK, vcpu->arch.xcr0);
@@ -1019,7 +1019,7 @@ void kvm_load_guest_xsave_state(struct kvm_vcpu *vcpu)
 	if (static_cpu_has(X86_FEATURE_PKU) &&
 	    vcpu->arch.pkru != vcpu->arch.host_pkru &&
 	    ((vcpu->arch.xcr0 & XFEATURE_MASK_PKRU) ||
-	     kvm_read_cr4_bits(vcpu, X86_CR4_PKE)))
+	     kvm_is_cr4_bit_set(vcpu, X86_CR4_PKE)))
 		write_pkru(vcpu->arch.pkru);
 #endif /* CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS */
 }
@@ -1033,14 +1033,14 @@ void kvm_load_host_xsave_state(struct kvm_vcpu *vcpu)
 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
 	if (static_cpu_has(X86_FEATURE_PKU) &&
 	    ((vcpu->arch.xcr0 & XFEATURE_MASK_PKRU) ||
-	     kvm_read_cr4_bits(vcpu, X86_CR4_PKE))) {
+	     kvm_is_cr4_bit_set(vcpu, X86_CR4_PKE))) {
 		vcpu->arch.pkru = rdpkru();
 		if (vcpu->arch.pkru != vcpu->arch.host_pkru)
 			write_pkru(vcpu->arch.host_pkru);
 	}
 #endif /* CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS */
 
-	if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE)) {
+	if (kvm_is_cr4_bit_set(vcpu, X86_CR4_OSXSAVE)) {
 
 		if (vcpu->arch.xcr0 != host_xcr0)
 			xsetbv(XCR_XFEATURE_ENABLED_MASK, host_xcr0);
@@ -1245,7 +1245,7 @@ static void kvm_invalidate_pcid(struct kvm_vcpu *vcpu, unsigned long pcid)
 	 * PCIDs for them are also 0, because MOV to CR3 always flushes the TLB
 	 * with PCIDE=0.
 	 */
-	if (!kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE))
+	if (!kvm_is_cr4_bit_set(vcpu, X86_CR4_PCIDE))
 		return;
 
 	for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++)
@@ -1260,9 +1260,7 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
 	bool skip_tlb_flush = false;
 	unsigned long pcid = 0;
 #ifdef CONFIG_X86_64
-	bool pcid_enabled = kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE);
-
-	if (pcid_enabled) {
+	if (kvm_is_cr4_bit_set(vcpu, X86_CR4_PCIDE)) {
 		skip_tlb_flush = cr3 & X86_CR3_PCID_NOFLUSH;
 		cr3 &= ~X86_CR3_PCID_NOFLUSH;
 		pcid = cr3 & X86_CR3_PCID_MASK;
@@ -5051,7 +5049,7 @@ static int kvm_vcpu_ioctl_x86_set_mce(struct kvm_vcpu *vcpu,
 		return 0;
 	if (mce->status & MCI_STATUS_UC) {
 		if ((vcpu->arch.mcg_status & MCG_STATUS_MCIP) ||
-		    !kvm_read_cr4_bits(vcpu, X86_CR4_MCE)) {
+		    !kvm_is_cr4_bit_set(vcpu, X86_CR4_MCE)) {
 			kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
 			return 0;
 		}
@@ -13254,7 +13252,7 @@ int kvm_handle_invpcid(struct kvm_vcpu *vcpu, unsigned long type, gva_t gva)
 		return 1;
 	}
 
-	pcid_enabled = kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE);
+	pcid_enabled = kvm_is_cr4_bit_set(vcpu, X86_CR4_PCIDE);
 
 	switch (type) {
 	case INVPCID_TYPE_INDIV_ADDR:

arch/x86/kvm/x86.h

@@ -123,7 +123,7 @@ static inline bool kvm_exception_is_soft(unsigned int nr)
 
 static inline bool is_protmode(struct kvm_vcpu *vcpu)
 {
-	return kvm_read_cr0_bits(vcpu, X86_CR0_PE);
+	return kvm_is_cr0_bit_set(vcpu, X86_CR0_PE);
 }
 
 static inline int is_long_mode(struct kvm_vcpu *vcpu)
@@ -193,7 +193,7 @@ static inline bool is_pae_paging(struct kvm_vcpu *vcpu)
 
 static inline u8 vcpu_virt_addr_bits(struct kvm_vcpu *vcpu)
 {
-	return kvm_read_cr4_bits(vcpu, X86_CR4_LA57) ? 57 : 48;
+	return kvm_is_cr4_bit_set(vcpu, X86_CR4_LA57) ? 57 : 48;
 }
 
 static inline bool is_noncanonical_address(u64 la, struct kvm_vcpu *vcpu)