[v5,17/30] KVM: Move out KVM arch PM hooks and hardware enable/disable logic

Commit Message

Isaku Yamahata Sept. 22, 2022, 6:20 p.m. UTC

From: Isaku Yamahata <[e-mail]>

To make clear that those files are default implementation and that KVM/x86
(and other KVM arch in future) will override them, split out those into a
dedicated file.  Once conversions for all kvm archs are done, the file will
be deleted.

Signed-off-by: Isaku Yamahata <[e-mail]>
---
 virt/kvm/Makefile.kvm |   2 +-
 virt/kvm/kvm_arch.c   | 164 ++++++++++++++++++++++++++++++++++++++++++
 virt/kvm/kvm_main.c   | 160 -----------------------------------------
 3 files changed, 165 insertions(+), 161 deletions(-)
 create mode 100644 virt/kvm/kvm_arch.c

Comments

Sean Christopherson Oct. 12, 2022, 9:10 p.m. UTC | #1

On Thu, Sep 22, 2022, [e-mail] wrote:
> From: Isaku Yamahata <[e-mail]>
> 
> To make clear that those files are default implementation

Heh, this is debatable, I was quite confused/surprised by seeing kvm_arch.c.  It's
also incomplete, which is further confusing, since there are a lot of default hooks
that are left behind.  And we most definitely don't want to move all of them, since
many of those hooks are pure nops, i.e. get completely compiled out.

Given that we want this code to go away sooner than later, I don't think adding
a temporarily to-be-deleted file makes sense.

Patch

diff --git a/virt/kvm/Makefile.kvm b/virt/kvm/Makefile.kvm
index 2c27d5d0c367..428b09b3f80a 100644
--- a/virt/kvm/Makefile.kvm
+++ b/virt/kvm/Makefile.kvm
@@ -5,7 +5,7 @@ 
 
 KVM ?= ../../../virt/kvm
 
-kvm-y := $(KVM)/kvm_main.o $(KVM)/eventfd.o $(KVM)/binary_stats.o
+kvm-y := $(KVM)/kvm_main.o $(KVM)/eventfd.o $(KVM)/binary_stats.o $(KVM)/kvm_arch.o
 kvm-$(CONFIG_KVM_VFIO) += $(KVM)/vfio.o
 kvm-$(CONFIG_KVM_MMIO) += $(KVM)/coalesced_mmio.o
 kvm-$(CONFIG_KVM_ASYNC_PF) += $(KVM)/async_pf.o
diff --git a/virt/kvm/kvm_arch.c b/virt/kvm/kvm_arch.c
new file mode 100644
index 000000000000..bcf8b74144e3
--- /dev/null
+++ b/virt/kvm/kvm_arch.c
@@ -0,0 +1,164 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kvm_arch.c: kvm default arch hooks for hardware enabling/disabling
+ * Copyright (c) 2022 Intel Corporation.
+ *
+ * Author:
+ *   Isaku Yamahata <[e-mail]>
+ *                  <[e-mail]>
+ *
+ * TODO: Delete this file once the conversion of all KVM arch is done.
+ */
+
+#include <linux/kvm_host.h>
+
+static cpumask_t cpus_hardware_enabled = CPU_MASK_NONE;
+static atomic_t hardware_enable_failed;
+
+/*
+ * Called after the VM is otherwise initialized, but just before adding it to
+ * the vm_list.
+ */
+int __weak kvm_arch_post_init_vm(struct kvm *kvm)
+{
+	return 0;
+}
+
+static void hardware_enable_nolock(void *junk)
+{
+	int cpu = raw_smp_processor_id();
+	int r;
+
+	WARN_ON_ONCE(preemptible());
+
+	if (cpumask_test_cpu(cpu, &cpus_hardware_enabled))
+		return;
+
+	cpumask_set_cpu(cpu, &cpus_hardware_enabled);
+
+	r = kvm_arch_hardware_enable();
+
+	if (r) {
+		cpumask_clear_cpu(cpu, &cpus_hardware_enabled);
+		atomic_inc(&hardware_enable_failed);
+		pr_warn("kvm: enabling virtualization on CPU%d failed during %pSb\n",
+			cpu, __builtin_return_address(0));
+	}
+}
+
+static void hardware_disable_nolock(void *junk)
+{
+	int cpu = raw_smp_processor_id();
+
+	WARN_ON_ONCE(preemptible());
+
+	if (!cpumask_test_cpu(cpu, &cpus_hardware_enabled))
+		return;
+	cpumask_clear_cpu(cpu, &cpus_hardware_enabled);
+	kvm_arch_hardware_disable();
+}
+
+/*
+ * Called after the VM is otherwise initialized, but just before adding it to
+ * the vm_list.
+ */
+int __weak kvm_arch_add_vm(struct kvm *kvm, int usage_count)
+{
+	int r = 0;
+
+	if (usage_count != 1)
+		return 0;
+
+	atomic_set(&hardware_enable_failed, 0);
+	on_each_cpu(hardware_enable_nolock, NULL, 1);
+
+	if (atomic_read(&hardware_enable_failed)) {
+		r = -EBUSY;
+		goto err;
+	}
+
+	r = kvm_arch_post_init_vm(kvm);
+err:
+	if (r)
+		on_each_cpu(hardware_disable_nolock, NULL, 1);
+	return r;
+}
+
+int __weak kvm_arch_del_vm(int usage_count)
+{
+	if (usage_count)
+		return 0;
+
+	on_each_cpu(hardware_disable_nolock, NULL, 1);
+	return 0;
+}
+
+int __weak kvm_arch_online_cpu(unsigned int cpu, int usage_count)
+{
+	int ret = 0;
+
+	ret = kvm_arch_check_processor_compat();
+	if (ret)
+		return ret;
+
+	/*
+	 * Abort the CPU online process if hardware virtualization cannot
+	 * be enabled. Otherwise running VMs would encounter unrecoverable
+	 * errors when scheduled to this CPU.
+	 */
+	if (usage_count) {
+		WARN_ON_ONCE(atomic_read(&hardware_enable_failed));
+
+		/*
+		 * arch callback kvm_arch_hardware_eanble() assumes that
+		 * preemption is disabled for historical reason.  Disable
+		 * preemption until all arch callbacks are fixed.
+		 */
+		preempt_disable();
+		hardware_enable_nolock(NULL);
+		preempt_enable();
+		if (atomic_read(&hardware_enable_failed)) {
+			atomic_set(&hardware_enable_failed, 0);
+			ret = -EIO;
+		}
+	}
+	return ret;
+}
+
+int __weak kvm_arch_offline_cpu(unsigned int cpu, int usage_count)
+{
+	if (usage_count) {
+		/*
+		 * arch callback kvm_arch_hardware_disable() assumes that
+		 * preemption is disabled for historical reason.  Disable
+		 * preemption until all arch callbacks are fixed.
+		 */
+		preempt_disable();
+		hardware_disable_nolock(NULL);
+		preempt_enable();
+	}
+	return 0;
+}
+
+int __weak kvm_arch_reboot(int val)
+{
+	on_each_cpu(hardware_disable_nolock, NULL, 1);
+	return NOTIFY_OK;
+}
+
+int __weak kvm_arch_suspend(int usage_count)
+{
+	if (usage_count)
+		/*
+		 * Because kvm_suspend() is called with interrupt disabled,  no
+		 * need to disable preemption.
+		 */
+		hardware_disable_nolock(NULL);
+	return 0;
+}
+
+void __weak kvm_arch_resume(int usage_count)
+{
+	if (usage_count)
+		hardware_enable_nolock(NULL);
+}
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index d7c3bc14691f..b1a09d2d5982 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -102,9 +102,7 @@  EXPORT_SYMBOL_GPL(halt_poll_ns_shrink);
 DEFINE_MUTEX(kvm_lock);
 LIST_HEAD(vm_list);
 
-static cpumask_var_t cpus_hardware_enabled;
 static int kvm_usage_count;
-static atomic_t hardware_enable_failed;
 
 static struct kmem_cache *kvm_vcpu_cache;
 
@@ -142,8 +140,6 @@  static int kvm_no_compat_open(struct inode *inode, struct file *file)
 #define KVM_COMPAT(c)	.compat_ioctl	= kvm_no_compat_ioctl,	\
 			.open		= kvm_no_compat_open
 #endif
-static void hardware_enable_nolock(void *junk);
-static void hardware_disable_nolock(void *junk);
 static void kvm_del_vm(void);
 
 static void kvm_io_bus_destroy(struct kvm_io_bus *bus);
@@ -1098,120 +1094,6 @@  static int kvm_create_vm_debugfs(struct kvm *kvm, const char *fdname)
 	return ret;
 }
 
-/*
- * Called after the VM is otherwise initialized, but just before adding it to
- * the vm_list.
- */
-int __weak kvm_arch_post_init_vm(struct kvm *kvm)
-{
-	return 0;
-}
-
-/*
- * Called after the VM is otherwise initialized, but just before adding it to
- * the vm_list.
- */
-int __weak kvm_arch_add_vm(struct kvm *kvm, int usage_count)
-{
-	int r = 0;
-
-	if (usage_count != 1)
-		return 0;
-
-	atomic_set(&hardware_enable_failed, 0);
-	on_each_cpu(hardware_enable_nolock, NULL, 1);
-
-	if (atomic_read(&hardware_enable_failed)) {
-		r = -EBUSY;
-		goto err;
-	}
-
-	r = kvm_arch_post_init_vm(kvm);
-err:
-	if (r)
-		on_each_cpu(hardware_disable_nolock, NULL, 1);
-	return r;
-}
-
-int __weak kvm_arch_del_vm(int usage_count)
-{
-	if (usage_count)
-		return 0;
-
-	on_each_cpu(hardware_disable_nolock, NULL, 1);
-	return 0;
-}
-
-int __weak kvm_arch_online_cpu(unsigned int cpu, int usage_count)
-{
-	int ret = 0;
-
-	ret = kvm_arch_check_processor_compat();
-	if (ret)
-		return ret;
-
-	/*
-	 * Abort the CPU online process if hardware virtualization cannot
-	 * be enabled. Otherwise running VMs would encounter unrecoverable
-	 * errors when scheduled to this CPU.
-	 */
-	if (usage_count) {
-		WARN_ON_ONCE(atomic_read(&hardware_enable_failed));
-
-		/*
-		 * arch callback kvm_arch_hardware_eanble() assumes that
-		 * preemption is disabled for historical reason.  Disable
-		 * preemption until all arch callbacks are fixed.
-		 */
-		preempt_disable();
-		hardware_enable_nolock(NULL);
-		preempt_enable();
-		if (atomic_read(&hardware_enable_failed)) {
-			atomic_set(&hardware_enable_failed, 0);
-			ret = -EIO;
-		}
-	}
-	return ret;
-}
-
-int __weak kvm_arch_offline_cpu(unsigned int cpu, int usage_count)
-{
-	if (usage_count) {
-		/*
-		 * arch callback kvm_arch_hardware_disable() assumes that
-		 * preemption is disabled for historical reason.  Disable
-		 * preemption until all arch callbacks are fixed.
-		 */
-		preempt_disable();
-		hardware_disable_nolock(NULL);
-		preempt_enable();
-	}
-	return 0;
-}
-
-int __weak kvm_arch_reboot(int val)
-{
-	on_each_cpu(hardware_disable_nolock, NULL, 1);
-	return NOTIFY_OK;
-}
-
-int __weak kvm_arch_suspend(int usage_count)
-{
-	if (usage_count)
-		/*
-		 * Because kvm_suspend() is called with interrupt disabled,  no
-		 * need to disable preemption.
-		 */
-		hardware_disable_nolock(NULL);
-	return 0;
-}
-
-void __weak kvm_arch_resume(int usage_count)
-{
-	if (usage_count)
-		hardware_enable_nolock(NULL);
-}
-
 /*
  * Called just after removing the VM from the vm_list, but before doing any
  * other destruction.
@@ -5106,28 +4988,6 @@  static struct miscdevice kvm_dev = {
 	&kvm_chardev_ops,
 };
 
-static void hardware_enable_nolock(void *junk)
-{
-	int cpu = raw_smp_processor_id();
-	int r;
-
-	WARN_ON_ONCE(preemptible());
-
-	if (cpumask_test_cpu(cpu, cpus_hardware_enabled))
-		return;
-
-	cpumask_set_cpu(cpu, cpus_hardware_enabled);
-
-	r = kvm_arch_hardware_enable();
-
-	if (r) {
-		cpumask_clear_cpu(cpu, cpus_hardware_enabled);
-		atomic_inc(&hardware_enable_failed);
-		pr_warn("kvm: enabling virtualization on CPU%d failed during %pSb\n",
-			cpu, __builtin_return_address(0));
-	}
-}
-
 static int kvm_online_cpu(unsigned int cpu)
 {
 	int ret;
@@ -5138,18 +4998,6 @@  static int kvm_online_cpu(unsigned int cpu)
 	return ret;
 }
 
-static void hardware_disable_nolock(void *junk)
-{
-	int cpu = raw_smp_processor_id();
-
-	WARN_ON_ONCE(preemptible());
-
-	if (!cpumask_test_cpu(cpu, cpus_hardware_enabled))
-		return;
-	cpumask_clear_cpu(cpu, cpus_hardware_enabled);
-	kvm_arch_hardware_disable();
-}
-
 static int kvm_offline_cpu(unsigned int cpu)
 {
 	int ret;
@@ -5930,11 +5778,6 @@  int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
 	if (r)
 		goto out_irqfd;
 
-	if (!zalloc_cpumask_var(&cpus_hardware_enabled, GFP_KERNEL)) {
-		r = -ENOMEM;
-		goto out_free_0;
-	}
-
 	r = kvm_arch_hardware_setup(opaque);
 	if (r < 0)
 		goto out_free_1;
@@ -6011,8 +5854,6 @@  int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
 out_free_2:
 	kvm_arch_hardware_unsetup();
 out_free_1:
-	free_cpumask_var(cpus_hardware_enabled);
-out_free_0:
 	kvm_irqfd_exit();
 out_irqfd:
 	kvm_arch_exit();
@@ -6037,7 +5878,6 @@  void kvm_exit(void)
 	kvm_arch_hardware_unsetup();
 	kvm_arch_exit();
 	kvm_irqfd_exit();
-	free_cpumask_var(cpus_hardware_enabled);
 	kvm_vfio_ops_exit();
 }
 EXPORT_SYMBOL_GPL(kvm_exit);