KVM: x86: Move CPU compat checks hook to kvm_x86_ops (from kvm_x86_init_ops)

Move the .check_processor_compatibility() callback from kvm_x86_init_ops
to kvm_x86_ops to allow a future patch to do compatibility checks during
CPU hotplug.

Do kvm_ops_update() before compat checks so that static_call() can be
used during compat checks.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Message-Id: <20221130230934.1014142-40-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm-x86-ops.h

@@ -14,6 +14,7 @@ BUILD_BUG_ON(1)
  * to make a definition optional, but in this case the default will
  * be __static_call_return0.
  */
+KVM_X86_OP(check_processor_compatibility)
 KVM_X86_OP(hardware_enable)
 KVM_X86_OP(hardware_disable)
 KVM_X86_OP(hardware_unsetup)

arch/x86/include/asm/kvm_host.h

@@ -1511,6 +1511,8 @@ static inline u16 kvm_lapic_irq_dest_mode(bool dest_mode_logical)
 struct kvm_x86_ops {
 	const char *name;
 
+	int (*check_processor_compatibility)(void);
+
 	int (*hardware_enable)(void);
 	void (*hardware_disable)(void);
 	void (*hardware_unsetup)(void);
@@ -1722,7 +1724,6 @@ struct kvm_x86_nested_ops {
 };
 
 struct kvm_x86_init_ops {
-	int (*check_processor_compatibility)(void);
 	int (*hardware_setup)(void);
 	unsigned int (*handle_intel_pt_intr)(void);
 

arch/x86/kvm/svm/svm.c

@@ -543,7 +543,7 @@ static bool kvm_is_svm_supported(void)
 	return true;
 }
 
-static int __init svm_check_processor_compat(void)
+static int svm_check_processor_compat(void)
 {
 	if (!kvm_is_svm_supported())
 		return -EIO;
@@ -4701,6 +4701,8 @@ static int svm_vm_init(struct kvm *kvm)
 static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.name = KBUILD_MODNAME,
 
+	.check_processor_compatibility = svm_check_processor_compat,
+
 	.hardware_unsetup = svm_hardware_unsetup,
 	.hardware_enable = svm_hardware_enable,
 	.hardware_disable = svm_hardware_disable,
@@ -5085,7 +5087,6 @@ static __init int svm_hardware_setup(void)
 
 static struct kvm_x86_init_ops svm_init_ops __initdata = {
 	.hardware_setup = svm_hardware_setup,
-	.check_processor_compatibility = svm_check_processor_compat,
 
 	.runtime_ops = &svm_x86_ops,
 	.pmu_ops = &amd_pmu_ops,

arch/x86/kvm/vmx/hyperv.c

@@ -526,7 +526,7 @@ int nested_evmcs_check_controls(struct vmcs12 *vmcs12)
 	}									\
 	while (0)
 
-__init void evmcs_sanitize_exec_ctrls(struct vmcs_config *vmcs_conf)
+void evmcs_sanitize_exec_ctrls(struct vmcs_config *vmcs_conf)
 {
 	evmcs_check_vmcs_conf(cpu_based_exec_ctrl, EXEC_CTRL);
 	evmcs_check_vmcs_conf(pin_based_exec_ctrl, PINCTRL);

arch/x86/kvm/vmx/hyperv.h

@@ -271,7 +271,7 @@ static inline void evmcs_load(u64 phys_addr)
 	vp_ap->enlighten_vmentry = 1;
 }
 
-__init void evmcs_sanitize_exec_ctrls(struct vmcs_config *vmcs_conf);
+void evmcs_sanitize_exec_ctrls(struct vmcs_config *vmcs_conf);
 #else /* !IS_ENABLED(CONFIG_HYPERV) */
 static __always_inline void evmcs_write64(unsigned long field, u64 value) {}
 static inline void evmcs_write32(unsigned long field, u32 value) {}

arch/x86/kvm/vmx/vmx.c

@@ -2551,8 +2551,7 @@ static bool cpu_has_perf_global_ctrl_bug(void)
 	return false;
 }
 
-static __init int adjust_vmx_controls(u32 ctl_min, u32 ctl_opt,
-				      u32 msr, u32 *result)
+static int adjust_vmx_controls(u32 ctl_min, u32 ctl_opt, u32 msr, u32 *result)
 {
 	u32 vmx_msr_low, vmx_msr_high;
 	u32 ctl = ctl_min | ctl_opt;
@@ -2570,7 +2569,7 @@ static __init int adjust_vmx_controls(u32 ctl_min, u32 ctl_opt,
 	return 0;
 }
 
-static __init u64 adjust_vmx_controls64(u64 ctl_opt, u32 msr)
+static u64 adjust_vmx_controls64(u64 ctl_opt, u32 msr)
 {
 	u64 allowed;
 
@@ -2579,8 +2578,8 @@ static __init u64 adjust_vmx_controls64(u64 ctl_opt, u32 msr)
 	return  ctl_opt & allowed;
 }
 
-static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf,
-				    struct vmx_capability *vmx_cap)
+static int setup_vmcs_config(struct vmcs_config *vmcs_conf,
+			     struct vmx_capability *vmx_cap)
 {
 	u32 vmx_msr_low, vmx_msr_high;
 	u32 _pin_based_exec_control = 0;
@@ -2746,7 +2745,7 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf,
 	return 0;
 }
 
-static bool __init kvm_is_vmx_supported(void)
+static bool kvm_is_vmx_supported(void)
 {
 	if (!cpu_has_vmx()) {
 		pr_err("CPU doesn't support VMX\n");
@@ -2762,7 +2761,7 @@ static bool __init kvm_is_vmx_supported(void)
 	return true;
 }
 
-static int __init vmx_check_processor_compat(void)
+static int vmx_check_processor_compat(void)
 {
 	struct vmcs_config vmcs_conf;
 	struct vmx_capability vmx_cap;
@@ -8147,6 +8146,8 @@ static void vmx_vm_destroy(struct kvm *kvm)
 static struct kvm_x86_ops vmx_x86_ops __initdata = {
 	.name = KBUILD_MODNAME,
 
+	.check_processor_compatibility = vmx_check_processor_compat,
+
 	.hardware_unsetup = vmx_hardware_unsetup,
 
 	.hardware_enable = vmx_hardware_enable,
@@ -8544,7 +8545,6 @@ static __init int hardware_setup(void)
 }
 
 static struct kvm_x86_init_ops vmx_init_ops __initdata = {
-	.check_processor_compatibility = vmx_check_processor_compat,
 	.hardware_setup = hardware_setup,
 	.handle_intel_pt_intr = NULL,
 

arch/x86/kvm/x86.c

@@ -9294,12 +9294,7 @@ static inline void kvm_ops_update(struct kvm_x86_init_ops *ops)
 	kvm_pmu_ops_update(ops->pmu_ops);
 }
 
-struct kvm_cpu_compat_check {
-	struct kvm_x86_init_ops *ops;
-	int *ret;
-};
-
-static int kvm_x86_check_processor_compatibility(struct kvm_x86_init_ops *ops)
+static int kvm_x86_check_processor_compatibility(void)
 {
 	struct cpuinfo_x86 *c = &cpu_data(smp_processor_id());
 
@@ -9309,19 +9304,16 @@ static int kvm_x86_check_processor_compatibility(struct kvm_x86_init_ops *ops)
 	    __cr4_reserved_bits(cpu_has, &boot_cpu_data))
 		return -EIO;
 
-	return ops->check_processor_compatibility();
+	return static_call(kvm_x86_check_processor_compatibility)();
 }
 
-static void kvm_x86_check_cpu_compat(void *data)
+static void kvm_x86_check_cpu_compat(void *ret)
 {
-	struct kvm_cpu_compat_check *c = data;
-
-	*c->ret = kvm_x86_check_processor_compatibility(c->ops);
+	*(int *)ret = kvm_x86_check_processor_compatibility();
 }
 
 static int __kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
 {
-	struct kvm_cpu_compat_check c;
 	u64 host_pat;
 	int r, cpu;
 
@@ -9392,12 +9384,12 @@ static int __kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
 	if (r != 0)
 		goto out_mmu_exit;
 
-	c.ret = &r;
-	c.ops = ops;
+	kvm_ops_update(ops);
+
 	for_each_online_cpu(cpu) {
-		smp_call_function_single(cpu, kvm_x86_check_cpu_compat, &c, 1);
+		smp_call_function_single(cpu, kvm_x86_check_cpu_compat, &r, 1);
 		if (r < 0)
-			goto out_hardware_unsetup;
+			goto out_unwind_ops;
 	}
 
 	/*
@@ -9405,8 +9397,6 @@ static int __kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
 	 * absolutely necessary, as most operations from this point forward
 	 * require unwinding.
 	 */
-	kvm_ops_update(ops);
-
 	kvm_timer_init();
 
 	if (pi_inject_timer == -1)
@@ -9442,8 +9432,9 @@ static int __kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
 	kvm_init_msr_list();
 	return 0;
 
-out_hardware_unsetup:
-	ops->runtime_ops->hardware_unsetup();
+out_unwind_ops:
+	kvm_x86_ops.hardware_enable = NULL;
+	static_call(kvm_x86_hardware_unsetup)();
 out_mmu_exit:
 	kvm_mmu_vendor_module_exit();
 out_free_percpu: