sw64: add memhotplug support for guest os

Sunway inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I56WV8

--------------------------------

This patch introduces memory-hotplug support for guest os, and it
should set CONFIG_KVM_MEMHOTLPUG=y on host to enable this feature.

Currently, only 1GB memory-hotplug granularity is supported, and
multiple granularity support will be implemented in the future.
Signed-off-by: NLu Feifei <lufeifei@wxiat.com>
Signed-off-by: NGu Zitao <guzitao@wxiat.com>

arch/sw_64/chip/chip3/chip.c

@@ -701,6 +701,11 @@ void handle_chip_irq(unsigned long type, unsigned long vector,
 		handle_irq(type);
 		set_irq_regs(old_regs);
 		return;
+	case INT_VT_HOTPLUG:
+		old_regs = set_irq_regs(regs);
+		handle_irq(type);
+		set_irq_regs(old_regs);
+		return;
 	case INT_PC0:
 		perf_irq(PERFMON_PC0, regs);
 		return;

arch/sw_64/include/asm/hcall.h

@@ -18,6 +18,7 @@ enum HCALL_TYPE {
 	HCALL_SWNET		= 20,   /* guest request swnet service */
 	HCALL_SWNET_IRQ		= 21,   /* guest request swnet intr */
 	HCALL_FATAL_ERROR	= 22,   /* guest fatal error, issued by hmcode */
+	HCALL_MEMHOTPLUG	= 23,   /* guest memory hotplug event */
 	NR_HCALL
 };
 

arch/sw_64/include/asm/irq_impl.h

@@ -32,6 +32,7 @@ enum sw64_irq_type {
 	INT_RTC		= 9,
 	INT_FAULT	= 10,
 	INT_VT_SERIAL	= 12,
+	INT_VT_HOTPLUG	= 13,
 	INT_DEV		= 17,
 	INT_NMI		= 18,
 	INT_LEGACY	= 31,

arch/sw_64/include/asm/kvm_asm.h

@@ -11,4 +11,7 @@
 #define SW64_KVM_EXIT_RESTART		17
 #define SW64_KVM_EXIT_FATAL_ERROR	22
 
+#ifdef CONFIG_KVM_MEMHOTPLUG
+#define SW64_KVM_EXIT_MEMHOTPLUG	23
+#endif
 #endif /* _ASM_SW64_KVM_ASM_H */

arch/sw_64/include/asm/kvm_host.h

@@ -29,7 +29,7 @@
 #include <asm/kvm_mmio.h>
 
 #define KVM_MAX_VCPUS 64
-#define KVM_USER_MEM_SLOTS 512
+#define KVM_USER_MEM_SLOTS 64
 
 #define KVM_HALT_POLL_NS_DEFAULT 0
 #define KVM_IRQCHIP_NUM_PINS     256
@@ -42,12 +42,16 @@
 #define KVM_PAGES_PER_HPAGE(x)  (KVM_HPAGE_SIZE(x) / PAGE_SIZE)
 
 struct kvm_arch_memory_slot {
-
+	unsigned long host_phys_addr;
+	bool valid;
 };
 
 struct kvm_arch {
 	unsigned long host_phys_addr;
 	unsigned long size;
+
+	/* segment table */
+	unsigned long *seg_pgd;
 };
 
 
@@ -100,6 +104,9 @@ struct kvm_vcpu_stat {
 	u64 halt_poll_invalid;
 };
 
+#ifdef CONFIG_KVM_MEMHOTPLUG
+void vcpu_mem_hotplug(struct kvm_vcpu *vcpu, unsigned long start_addr);
+#endif
 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 		int exception_index, struct hcall_args *hargs);
 void vcpu_send_ipi(struct kvm_vcpu *vcpu, int target_vcpuid);

arch/sw_64/include/asm/memory.h

@@ -6,6 +6,7 @@
 #include <linux/numa.h>
 #endif
 
+#define MIN_MEMORY_BLOCK_SIZE_VM_MEMHP    (1UL << 30)
 #define NODE0_START	(_TEXT_START - __START_KERNEL_map)
 
 #define MAX_PHYSMEM_BITS	48

arch/sw_64/kvm/Kconfig

@@ -42,6 +42,13 @@ config KVM_SW64_HOST
 	  Provides host support for SW64 processors.
 	  To compile this as a module, choose M here.
 
+config KVM_MEMHOTPLUG
+	bool "Memory hotplug support for guest"
+	depends on KVM
+	help
+	  Provides memory hotplug support for SW64 guest.
+
+
 source "drivers/vhost/Kconfig"
 
 endif # VIRTUALIZATION

arch/sw_64/kvm/handle_exit.c

@@ -34,6 +34,11 @@ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 	case SW64_KVM_EXIT_IPI:
 		vcpu_send_ipi(vcpu, hargs->arg0);
 		return 1;
+#ifdef CONFIG_KVM_MEMHOTPLUG
+	case SW64_KVM_EXIT_MEMHOTPLUG:
+		vcpu_mem_hotplug(vcpu, hargs->arg0);
+		return 1;
+#endif
 	case SW64_KVM_EXIT_FATAL_ERROR:
 		printk("Guest fatal error: Reason=[%lx], EXC_PC=[%lx], DVA=[%lx]", hargs->arg0, hargs->arg1, hargs->arg2);
 		vcpu->run->exit_reason = KVM_EXIT_UNKNOWN;

arch/sw_64/kvm/kvm-sw64.c

@@ -56,10 +56,18 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm, int irq
 
 extern int __sw64_vcpu_run(struct vcpucb *vcb, struct kvm_regs *regs, struct hcall_args *args);
 
-static unsigned long get_vpcr(unsigned long machine_mem_offset, unsigned long memory_size, unsigned long vpn)
+#ifdef CONFIG_KVM_MEMHOTPLUG
+static u64 get_vpcr_memhp(u64 seg_base, u64 vpn)
 {
-	return (machine_mem_offset >> 23) | ((memory_size >> 23) << 16) | ((vpn & HARDWARE_VPN_MASK) << 44);
+	return seg_base | ((vpn & HARDWARE_VPN_MASK) << 44);
 }
+#else
+static u64 get_vpcr(u64 hpa_base, u64 mem_size, u64 vpn)
+{
+	return (hpa_base >> 23) | ((mem_size >> 23) << 16)
+				| ((vpn & HARDWARE_VPN_MASK) << 44);
+}
+#endif
 
 static unsigned long __get_new_vpn_context(struct kvm_vcpu *vcpu, long cpu)
 {
@@ -212,12 +220,38 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 
 int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 {
+#ifdef CONFIG_KVM_MEMHOTPLUG
+	unsigned long *seg_pgd;
+
+	if (kvm->arch.seg_pgd != NULL) {
+		kvm_err("kvm_arch already initialized?\n");
+		return -EINVAL;
+	}
+
+	seg_pgd = alloc_pages_exact(PAGE_SIZE, GFP_KERNEL | __GFP_ZERO);
+	if (!seg_pgd)
+		return -ENOMEM;
+
+	kvm->arch.seg_pgd = seg_pgd;
+#endif
+
 	return 0;
 }
 
 void kvm_arch_destroy_vm(struct kvm *kvm)
 {
 	int i;
+#ifdef CONFIG_KVM_MEMHOTPLUG
+	void *seg_pgd = NULL;
+
+	if (kvm->arch.seg_pgd) {
+		seg_pgd = READ_ONCE(kvm->arch.seg_pgd);
+		kvm->arch.seg_pgd = NULL;
+	}
+
+	if (seg_pgd)
+		free_pages_exact(seg_pgd, PAGE_SIZE);
+#endif
 
 	for (i = 0; i < KVM_MAX_VCPUS; ++i) {
 		if (kvm->vcpus[i]) {
@@ -227,7 +261,6 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
 	}
 
 	atomic_set(&kvm->online_vcpus, 0);
-
 }
 
 long kvm_arch_dev_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
@@ -241,6 +274,22 @@ int kvm_arch_create_memslot(struct kvm *kvm, struct kvm_memory_slot *slot,
 	return 0;
 }
 
+#ifdef CONFIG_KVM_MEMHOTPLUG
+static void setup_segment_table(struct kvm *kvm,
+	struct kvm_memory_slot *memslot, unsigned long addr, size_t size)
+{
+	unsigned long *seg_pgd = kvm->arch.seg_pgd;
+	unsigned int num_of_entry = size >> 30;
+	unsigned long base_hpa = addr >> 30;
+	int i;
+
+	for (i = 0; i < num_of_entry; i++) {
+		*seg_pgd = base_hpa + i;
+		seg_pgd++;
+	}
+}
+#endif
+
 int kvm_arch_prepare_memory_region(struct kvm *kvm,
 		struct kvm_memory_slot *memslot,
 		const struct kvm_userspace_memory_region *mem,
@@ -253,8 +302,15 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 	unsigned long ret;
 	size_t size;
 
-	if (change == KVM_MR_FLAGS_ONLY)
+	if (change == KVM_MR_FLAGS_ONLY || change == KVM_MR_DELETE)
+		return 0;
+
+#ifndef CONFIG_KVM_MEMHOTPLUG
+	if (mem->guest_phys_addr) {
+		pr_info("%s, No KVM MEMHOTPLUG support!\n", __func__);
 		return 0;
+	}
+#endif
 
 	if (test_bit(IO_MARK_BIT, &(mem->guest_phys_addr)))
 		return 0;
@@ -276,7 +332,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 	if (!vm_file) {
 		info = kzalloc(sizeof(struct vmem_info), GFP_KERNEL);
 
-		size = round_up(mem->memory_size, 8<<20);
+		size = round_up(mem->memory_size, 8 << 20);
 		addr = gen_pool_alloc(sw64_kvm_pool, size);
 		if (!addr)
 			return -ENOMEM;
@@ -291,6 +347,18 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 		if (!vma)
 			return -ENOMEM;
 
+#ifdef CONFIG_KVM_MEMHOTPLUG
+		if (memslot->base_gfn == 0x0UL) {
+			setup_segment_table(kvm, memslot, addr, size);
+			kvm->arch.host_phys_addr = (u64)addr;
+			memslot->arch.host_phys_addr = addr;
+		} else {
+			/* used for memory hotplug */
+			memslot->arch.host_phys_addr = addr;
+			memslot->arch.valid = false;
+		}
+#endif
+
 		info->start = addr;
 		info->size = size;
 		vma->vm_private_data = (void *) info;
@@ -308,8 +376,11 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 
 	pr_info("guest phys addr = %#lx, size = %#lx\n",
 			addr, vma->vm_end - vma->vm_start);
+
+#ifndef CONFIG_KVM_MEMHOTPLUG
 	kvm->arch.host_phys_addr = (u64)addr;
-	kvm->arch.size = round_up(mem->memory_size, 8<<20);
+	kvm->arch.size = round_up(mem->memory_size, 8 << 20);
+#endif
 
 	memset(__va(addr), 0, 0x2000000);
 
@@ -463,8 +534,14 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 	/* Set guest vcb */
 	/* vpn will update later when vcpu is running */
 	if (vcpu->arch.vcb.vpcr == 0) {
+#ifndef CONFIG_KVM_MEMHOTPLUG
 		vcpu->arch.vcb.vpcr
 			= get_vpcr(vcpu->kvm->arch.host_phys_addr, vcpu->kvm->arch.size, 0);
+#else
+		unsigned long seg_base = virt_to_phys(vcpu->kvm->arch.seg_pgd);
+
+		vcpu->arch.vcb.vpcr = get_vpcr_memhp(seg_base, 0);
+#endif
 		vcpu->arch.vcb.upcr = 0x7;
 	}
 
@@ -640,6 +717,30 @@ int kvm_dev_ioctl_check_extension(long ext)
 	return r;
 }
 
+#ifdef CONFIG_KVM_MEMHOTPLUG
+void vcpu_mem_hotplug(struct kvm_vcpu *vcpu, unsigned long start_addr)
+{
+	struct kvm *kvm = vcpu->kvm;
+	struct kvm_memory_slot *slot;
+	unsigned long start_pfn = start_addr >> PAGE_SHIFT;
+
+	kvm_for_each_memslot(slot, kvm_memslots(kvm)) {
+		if (start_pfn == slot->base_gfn) {
+			unsigned long *seg_pgd;
+			unsigned long num_of_entry = slot->npages >> 17;
+			unsigned long base_hpa = slot->arch.host_phys_addr;
+			int i;
+
+			seg_pgd = kvm->arch.seg_pgd + (start_pfn >> 17);
+			for (i = 0; i < num_of_entry; i++) {
+				*seg_pgd = (base_hpa >> 30) + i;
+				seg_pgd++;
+			}
+		}
+	}
+}
+#endif
+
 void vcpu_send_ipi(struct kvm_vcpu *vcpu, int target_vcpuid)
 {
 	struct kvm_vcpu *target_vcpu = kvm_get_vcpu(vcpu->kvm, target_vcpuid);

arch/sw_64/mm/init.c

@@ -10,6 +10,7 @@
 #include <linux/memblock.h>
 #include <linux/swiotlb.h>
 #include <linux/acpi.h>
+#include <linux/memory.h>
 
 #include <asm/mmu_context.h>
 
@@ -33,6 +34,14 @@ static pud_t vmalloc_pud[1024]	__attribute__((__aligned__(PAGE_SIZE)));
 static phys_addr_t mem_start;
 static phys_addr_t mem_size_limit;
 
+unsigned long memory_block_size_bytes(void)
+{
+	if (is_in_guest())
+		return MIN_MEMORY_BLOCK_SIZE_VM_MEMHP;
+	else
+		return MIN_MEMORY_BLOCK_SIZE;
+}
+
 static int __init setup_mem_size(char *p)
 {
 	char *oldp;

drivers/misc/Kconfig

@@ -351,6 +351,14 @@ config HMC6352
 	  This driver provides support for the Honeywell HMC6352 compass,
 	  providing configuration and heading data via sysfs.
 
+config SUNWAY_GED
+	tristate "sunway generic device driver for memhotplug"
+	depends on SW64
+	depends on MEMORY_HOTPLUG
+	help
+	  This driver provides support for sunway generic device driver for
+	  memhotplug, providing configuration and heading data via sysfs.
+
 config DS1682
 	tristate "Dallas DS1682 Total Elapsed Time Recorder with Alarm"
 	depends on I2C

drivers/misc/Makefile

@@ -34,6 +34,7 @@ obj-$(CONFIG_SENSORS_TSL2550)	+= tsl2550.o
 obj-$(CONFIG_DS1682)		+= ds1682.o
 obj-$(CONFIG_C2PORT)		+= c2port/
 obj-$(CONFIG_HMC6352)		+= hmc6352.o
+obj-$(CONFIG_SUNWAY_GED)	+= sunway-ged.o
 obj-y				+= eeprom/
 obj-y				+= cb710/
 obj-$(CONFIG_VMWARE_BALLOON)	+= vmw_balloon.o

drivers/misc/sunway-ged.c

+// SPDX-License-Identifier: GPL-2.0
+
+/* Generic Event Device for ACPI. */
+
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+
+#define OFFSET_START_ADDR	0
+#define OFFSET_LENGTH		8
+#define OFFSET_STATUS		16
+#define OFFSET_SLOT		24
+
+/* Memory hotplug event */
+#define SUNWAY_MEMHOTPLUG_ADD		0x1
+#define SUNWAY_MEMHOTPLUG_REMOVE	0x2
+
+struct sunway_memory_device {
+	struct sunway_ged_device *device;
+	unsigned int state;     /* State of the memory device */
+	struct list_head list;
+
+	u64 start_addr;         /* Memory Range start physical addr */
+	u64 length;             /* Memory Range length */
+	u64 slot;		/* Memory Range slot */
+	unsigned int enabled:1;
+};
+
+struct sunway_ged_device {
+	struct device *dev;
+	void __iomem *membase;
+	void *driver_data;
+	spinlock_t lock;
+	struct list_head dev_list;
+};
+
+static int sunway_memory_enable_device(struct sunway_memory_device *mem_device)
+{
+	int num_enabled = 0;
+	int result = 0;
+
+	if (mem_device->enabled) {	/* just sanity check...*/
+		num_enabled++;
+		goto out;
+	}
+
+	/*
+	 * If the memory block size is zero, please ignore it.
+	 * Don't try to do the following memory hotplug flowchart.
+	 */
+	if (!mem_device->length)
+		goto out;
+
+	lock_device_hotplug();
+	/* suppose node = 0, fix me! */
+	result = __add_memory(0, mem_device->start_addr, mem_device->length);
+	unlock_device_hotplug();
+	/*
+	 * If the memory block has been used by the kernel, add_memory()
+	 * returns -EEXIST. If add_memory() returns the other error, it
+	 * means that this memory block is not used by the kernel.
+	 */
+	if (result && result != -EEXIST)
+		goto out;
+
+	mem_device->enabled = 1;
+
+	/*
+	 * Add num_enable even if add_memory() returns -EEXIST, so the
+	 * device is bound to this driver.
+	 */
+	num_enabled++;
+out:
+	if (!num_enabled) {
+		dev_err(mem_device->device->dev, "add_memory failed\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int sunway_memory_get_meminfo(struct sunway_memory_device *mem_device)
+{
+	struct sunway_ged_device *geddev;
+
+	if (!mem_device)
+		return -EINVAL;
+
+	if (mem_device->enabled)
+		return 0;
+
+	geddev = mem_device->device;
+
+	mem_device->start_addr = readq(geddev->membase + OFFSET_START_ADDR);
+	mem_device->length = readq(geddev->membase + OFFSET_LENGTH);
+
+	return 0;
+}
+
+static void sunway_memory_device_remove(struct sunway_ged_device *device)
+{
+	struct sunway_memory_device *mem_dev, *n;
+	unsigned long start_addr, length, slot;
+
+	if (!device)
+		return;
+
+	start_addr = readq(device->membase + OFFSET_START_ADDR);
+	length = readq(device->membase + OFFSET_LENGTH);
+	slot = readq(device->membase + OFFSET_SLOT);
+
+	list_for_each_entry_safe(mem_dev, n, &device->dev_list, list) {
+		if (!mem_dev->enabled)
+			continue;
+
+		if ((start_addr == mem_dev->start_addr) &&
+				(length == mem_dev->length)) {
+			/* suppose node = 0, fix me! */
+			remove_memory(0, start_addr, length);
+			list_del(&mem_dev->list);
+			kfree(mem_dev);
+		}
+	}
+
+	writeq(slot, device->membase + OFFSET_SLOT);
+}
+
+static int sunway_memory_device_add(struct sunway_ged_device *device)
+{
+	struct sunway_memory_device *mem_device;
+	int result;
+
+	if (!device)
+		return -EINVAL;
+
+	mem_device = kzalloc(sizeof(struct sunway_memory_device), GFP_KERNEL);
+	if (!mem_device)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&mem_device->list);
+	mem_device->device = device;
+
+	/* Get the range from the IO */
+	mem_device->start_addr = readq(device->membase + OFFSET_START_ADDR);
+	mem_device->length = readq(device->membase + OFFSET_LENGTH);
+	mem_device->slot = readq(device->membase + OFFSET_SLOT);
+
+	result = sunway_memory_enable_device(mem_device);
+	if (result) {
+		dev_err(device->dev, "sunway_memory_enable_device() error\n");
+		sunway_memory_device_remove(device);
+
+		return result;
+	}
+
+	list_add_tail(&mem_device->list, &device->dev_list);
+	dev_dbg(device->dev, "Memory device configured\n");
+
+	hcall(HCALL_MEMHOTPLUG, mem_device->start_addr, 0, 0);
+
+	return 1;
+}
+
+static irqreturn_t sunwayged_ist(int irq, void *data)
+{
+	struct sunway_ged_device *sunwayged_dev = data;
+	unsigned int status;
+
+	status = readl(sunwayged_dev->membase + OFFSET_STATUS);
+
+	/* through IO status to add or remove memory device  */
+	if (status & SUNWAY_MEMHOTPLUG_ADD)
+		sunway_memory_device_add(sunwayged_dev);
+
+	if (status & SUNWAY_MEMHOTPLUG_REMOVE)
+		sunway_memory_device_remove(sunwayged_dev);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t sunwayged_irq_handler(int irq, void *data)
+{
+	return IRQ_WAKE_THREAD;
+}
+
+static int sunwayged_probe(struct platform_device *pdev)
+{
+	struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	int irq = platform_get_irq(pdev, 0);
+	struct sunway_ged_device *geddev;
+	struct device *dev;
+	int irqflags;
+
+	if (!regs) {
+		dev_err(dev, "no registers defined\n");
+		return -EINVAL;
+	}
+
+	geddev = devm_kzalloc(&pdev->dev, sizeof(*geddev), GFP_KERNEL);
+	if (!geddev)
+		return -ENOMEM;
+
+	spin_lock_init(&geddev->lock);
+	geddev->membase = devm_ioremap(&pdev->dev,
+					regs->start, resource_size(regs));
+	if (!geddev->membase)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&geddev->dev_list);
+	geddev->dev = &pdev->dev;
+	irqflags = IRQF_SHARED;
+
+	if (request_threaded_irq(irq, sunwayged_irq_handler, sunwayged_ist,
+				irqflags, "SUNWAY:Ged", geddev)) {
+		dev_err(dev, "failed to setup event handler for irq %u\n", irq);
+
+		return -EINVAL;
+	}
+
+	platform_set_drvdata(pdev, geddev);
+
+	return 0;
+}
+
+static int sunwayged_remove(struct platform_device *pdev)
+{
+	return 0;
+}
+
+static const struct of_device_id sunwayged_of_match[] = {
+	{.compatible = "sw6,sunway-ged", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, sunwayged_of_match);
+
+static struct platform_driver sunwayged_platform_driver = {
+	.driver = {
+		.name		= "sunway-ged",
+		.of_match_table	= sunwayged_of_match,
+	},
+	.probe			= sunwayged_probe,
+	.remove			= sunwayged_remove,
+};
+module_platform_driver(sunwayged_platform_driver);
+
+MODULE_AUTHOR("Lu Feifei");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Sunway ged driver");