[PATCH V3 10/14] KVM: MIPS: Add Loongson-3 Virtual IPI interrupt support

Huacai Chen
2020-05-03T10:14:24Z

This patch add Loongson-3 Virtual IPI interrupt support in the kernel,
because emulate it in QEMU is too expensive for performance.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Co-developed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
---
arch/mips/include/asm/kvm_host.h | 32 ++++++
arch/mips/kvm/Makefile | 3 +
arch/mips/kvm/emulate.c | 23 ++++-
arch/mips/kvm/loongson_ipi.c | 214 +++++++++++++++++++++++++++++++++++++++
arch/mips/kvm/mips.c | 6 ++
5 files changed, 277 insertions(+), 1 deletion(-)
create mode 100644 arch/mips/kvm/loongson_ipi.c

diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index a7758c0..f165902 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -23,6 +23,8 @@
#include <asm/inst.h>
#include <asm/mipsregs.h>

+#include <kvm/iodev.h>
+
/* MIPS KVM register ids */
#define MIPS_CP0_32(_R, _S) \
(KVM_REG_MIPS_CP0 | KVM_REG_SIZE_U32 | (8 * (_R) + (_S)))
@@ -181,11 +183,39 @@ struct kvm_vcpu_stat {
struct kvm_arch_memory_slot {
};

+#ifdef CONFIG_CPU_LOONGSON64
+struct ipi_state {
+ uint32_t status;
+ uint32_t en;
+ uint32_t set;
+ uint32_t clear;
+ uint64_t buf[4];
+};
+
+struct loongson_kvm_ipi;
+
+struct ipi_io_device {
+ int node_id;
+ struct loongson_kvm_ipi *ipi;
+ struct kvm_io_device device;
+};
+
+struct loongson_kvm_ipi {
+ spinlock_t lock;
+ struct kvm *kvm;
+ struct ipi_state ipistate[16];
+ struct ipi_io_device dev_ipi[4];
+};
+#endif
+
struct kvm_arch {
/* Guest physical mm */
struct mm_struct gpa_mm;
/* Mask of CPUs needing GPA ASID flush */
cpumask_t asid_flush_mask;
+#ifdef CONFIG_CPU_LOONGSON64
+ struct loongson_kvm_ipi ipi;
+#endif
};

#define N_MIPS_COPROC_REGS 32
@@ -1133,6 +1163,8 @@ extern int kvm_mips_trans_mtc0(union mips_instruction inst, u32 *opc,
/* Misc */
extern void kvm_mips_dump_stats(struct kvm_vcpu *vcpu);
extern unsigned long kvm_mips_get_ramsize(struct kvm *kvm);
+extern int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu,
+ struct kvm_mips_interrupt *irq);

static inline void kvm_arch_hardware_unsetup(void) {}
static inline void kvm_arch_sync_events(struct kvm *kvm) {}
diff --git a/arch/mips/kvm/Makefile b/arch/mips/kvm/Makefile
index 0a3cef6..506c4ac 100644
--- a/arch/mips/kvm/Makefile
+++ b/arch/mips/kvm/Makefile
@@ -13,6 +13,9 @@ kvm-objs := $(common-objs-y) mips.o emulate.o entry.o \
fpu.o
kvm-objs += hypcall.o
kvm-objs += mmu.o
+ifdef CONFIG_CPU_LOONGSON64
+kvm-objs += loongson_ipi.o
+endif

ifdef CONFIG_KVM_MIPS_VZ
kvm-objs += vz.o
diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
index 754094b..3946499 100644
--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -1600,6 +1600,7 @@ enum emulation_result kvm_mips_emulate_store(union mips_instruction inst,
struct kvm_run *run,
struct kvm_vcpu *vcpu)
{
+ int r;
enum emulation_result er;
u32 rt;
void *data = run->mmio.data;
@@ -1666,9 +1667,18 @@ enum emulation_result kvm_mips_emulate_store(union mips_instruction inst,
goto out_fail;
}

- run->mmio.is_write = 1;
vcpu->mmio_needed = 1;
+ run->mmio.is_write = 1;
vcpu->mmio_is_write = 1;
+
+ r = kvm_io_bus_write(vcpu, KVM_MMIO_BUS,
+ run->mmio.phys_addr, run->mmio.len, data);
+
+ if (!r) {
+ vcpu->mmio_needed = 0;
+ return EMULATE_DONE;
+ }
+
return EMULATE_DO_MMIO;

out_fail:
@@ -1681,6 +1691,7 @@ enum emulation_result kvm_mips_emulate_load(union mips_instruction inst,
u32 cause, struct kvm_run *run,
struct kvm_vcpu *vcpu)
{
+ int r;
enum emulation_result er;
unsigned long curr_pc;
u32 op, rt;
@@ -1745,6 +1756,16 @@ enum emulation_result kvm_mips_emulate_load(union mips_instruction inst,

run->mmio.is_write = 0;
vcpu->mmio_is_write = 0;
+
+ r = kvm_io_bus_read(vcpu, KVM_MMIO_BUS,
+ run->mmio.phys_addr, run->mmio.len, run->mmio.data);
+
+ if (!r) {
+ kvm_mips_complete_mmio_load(vcpu, run);
+ vcpu->mmio_needed = 0;
+ return EMULATE_DONE;
+ }
+
return EMULATE_DO_MMIO;
}

diff --git a/arch/mips/kvm/loongson_ipi.c b/arch/mips/kvm/loongson_ipi.c
new file mode 100644
index 00000000..3681fc8
--- /dev/null
+++ b/arch/mips/kvm/loongson_ipi.c
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Loongson-3 Virtual IPI interrupt support.
+ *
+ * Copyright (C) 2019 Loongson Technologies, Inc. All rights reserved.
+ *
+ * Authors: Chen Zhu <zhuchen@loongson.cn>
+ * Authors: Huacai Chen <chenhc@lemote.com>
+ */
+
+#include <linux/kvm_host.h>
+
+#define IPI_BASE 0x3ff01000ULL
+
+#define CORE0_STATUS_OFF 0x000
+#define CORE0_EN_OFF 0x004
+#define CORE0_SET_OFF 0x008
+#define CORE0_CLEAR_OFF 0x00c
+#define CORE0_BUF_20 0x020
+#define CORE0_BUF_28 0x028
+#define CORE0_BUF_30 0x030
+#define CORE0_BUF_38 0x038
+
+#define CORE1_STATUS_OFF 0x100
+#define CORE1_EN_OFF 0x104
+#define CORE1_SET_OFF 0x108
+#define CORE1_CLEAR_OFF 0x10c
+#define CORE1_BUF_20 0x120
+#define CORE1_BUF_28 0x128
+#define CORE1_BUF_30 0x130
+#define CORE1_BUF_38 0x138
+
+#define CORE2_STATUS_OFF 0x200
+#define CORE2_EN_OFF 0x204
+#define CORE2_SET_OFF 0x208
+#define CORE2_CLEAR_OFF 0x20c
+#define CORE2_BUF_20 0x220
+#define CORE2_BUF_28 0x228
+#define CORE2_BUF_30 0x230
+#define CORE2_BUF_38 0x238
+
+#define CORE3_STATUS_OFF 0x300
+#define CORE3_EN_OFF 0x304
+#define CORE3_SET_OFF 0x308
+#define CORE3_CLEAR_OFF 0x30c
+#define CORE3_BUF_20 0x320
+#define CORE3_BUF_28 0x328
+#define CORE3_BUF_30 0x330
+#define CORE3_BUF_38 0x338
+
+static int loongson_vipi_read(struct loongson_kvm_ipi *ipi,
+ gpa_t addr, int len, void *val)
+{
+ uint32_t core = (addr >> 8) & 3;
+ uint32_t node = (addr >> 44) & 3;
+ uint32_t id = core + node * 4;
+ uint64_t offset = addr & 0xff;
+ void *pbuf;
+ struct ipi_state *s = &(ipi->ipistate[id]);
+
+ BUG_ON(offset & (len - 1));
+
+ switch (offset) {
+ case CORE0_STATUS_OFF:
+ *(uint64_t *)val = s->status;
+ break;
+
+ case CORE0_EN_OFF:
+ *(uint64_t *)val = s->en;
+ break;
+
+ case CORE0_SET_OFF:
+ *(uint64_t *)val = 0;
+ break;
+
+ case CORE0_CLEAR_OFF:
+ *(uint64_t *)val = 0;
+ break;
+
+ case CORE0_BUF_20 ... CORE0_BUF_38:
+ pbuf = (void *)s->buf + (offset - 0x20);
+ if (len == 8)
+ *(uint64_t *)val = *(uint64_t *)pbuf;
+ else /* Assume len == 4 */
+ *(uint32_t *)val = *(uint32_t *)pbuf;
+ break;
+
+ default:
+ pr_notice("%s with unknown addr %llx\n", __func__, addr);
+ break;
+ }
+
+ return 0;
+}
+
+static int loongson_vipi_write(struct loongson_kvm_ipi *ipi,
+ gpa_t addr, int len, const void *val)
+{
+ uint32_t core = (addr >> 8) & 3;
+ uint32_t node = (addr >> 44) & 3;
+ uint32_t id = core + node * 4;
+ uint64_t data, offset = addr & 0xff;
+ void *pbuf;
+ struct kvm *kvm = ipi->kvm;
+ struct kvm_mips_interrupt irq;
+ struct ipi_state *s = &(ipi->ipistate[id]);
+
+ data = *(uint64_t *)val;
+ BUG_ON(offset & (len - 1));
+
+ switch (offset) {
+ case CORE0_STATUS_OFF:
+ break;
+
+ case CORE0_EN_OFF:
+ s->en = data;
+ break;
+
+ case CORE0_SET_OFF:
+ s->status |= data;
+ irq.cpu = id;
+ irq.irq = 6;
+ kvm_vcpu_ioctl_interrupt(kvm->vcpus[id], &irq);
+ break;
+
+ case CORE0_CLEAR_OFF:
+ s->status &= ~data;
+ if (!s->status) {
+ irq.cpu = id;
+ irq.irq = -6;
+ kvm_vcpu_ioctl_interrupt(kvm->vcpus[id], &irq);
+ }
+ break;
+
+ case CORE0_BUF_20 ... CORE0_BUF_38:
+ pbuf = (void *)s->buf + (offset - 0x20);
+ if (len == 8)
+ *(uint64_t *)pbuf = (uint64_t)data;
+ else /* Assume len == 4 */
+ *(uint32_t *)pbuf = (uint32_t)data;
+ break;
+
+ default:
+ pr_notice("%s with unknown addr %llx\n", __func__, addr);
+ break;
+ }
+
+ return 0;
+}
+
+static int kvm_ipi_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
+ gpa_t addr, int len, void *val)
+{
+ unsigned long flags;
+ struct loongson_kvm_ipi *ipi;
+ struct ipi_io_device *ipi_device;
+
+ ipi_device = container_of(dev, struct ipi_io_device, device);
+ ipi = ipi_device->ipi;
+
+ spin_lock_irqsave(&ipi->lock, flags);
+ loongson_vipi_read(ipi, addr, len, val);
+ spin_unlock_irqrestore(&ipi->lock, flags);
+
+ return 0;
+}
+
+static int kvm_ipi_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
+ gpa_t addr, int len, const void *val)
+{
+ unsigned long flags;
+ struct loongson_kvm_ipi *ipi;
+ struct ipi_io_device *ipi_device;
+
+ ipi_device = container_of(dev, struct ipi_io_device, device);
+ ipi = ipi_device->ipi;
+
+ spin_lock_irqsave(&ipi->lock, flags);
+ loongson_vipi_write(ipi, addr, len, val);
+ spin_unlock_irqrestore(&ipi->lock, flags);
+
+ return 0;
+}
+
+static const struct kvm_io_device_ops kvm_ipi_ops = {
+ .read = kvm_ipi_read,
+ .write = kvm_ipi_write,
+};
+
+void kvm_init_loongson_ipi(struct kvm *kvm)
+{
+ int i;
+ unsigned long addr;
+ struct loongson_kvm_ipi *s;
+ struct kvm_io_device *device;
+
+ s = &kvm->arch.ipi;
+ s->kvm = kvm;
+ spin_lock_init(&s->lock);
+
+ /*
+ * Initialize IPI device
+ */
+ for (i = 0; i < 4; i++) {
+ device = &s->dev_ipi[i].device;
+ kvm_iodevice_init(device, &kvm_ipi_ops);
+ addr = (((unsigned long)i) << 44) + IPI_BASE;
+ mutex_lock(&kvm->slots_lock);
+ kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, addr, 0x400, device);
+ mutex_unlock(&kvm->slots_lock);
+ s->dev_ipi[i].ipi = s;
+ s->dev_ipi[i].node_id = i;
+ }
+}
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 5ca122c..ed989ef 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -128,6 +128,8 @@ int kvm_arch_check_processor_compat(void *opaque)
return 0;
}

+extern void kvm_init_loongson_ipi(struct kvm *kvm);
+
int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
{
switch (type) {
@@ -147,6 +149,10 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
if (!kvm->arch.gpa_mm.pgd)
return -ENOMEM;

+#ifdef CONFIG_CPU_LOONGSON64
+ kvm_init_loongson_ipi(kvm);
+#endif
+
return 0;
}

--
2.7.0