[PATCH V3 03/11] LoongArch: KVM: Add IPI read and write function

From: Xianglai Li
Date: Tue Sep 10 2024 - 07:59:22 EST


Implementation of IPI interrupt controller address
space read and write function simulation.

Signed-off-by: Min Zhou <zhoumin@xxxxxxxxxxx>
Signed-off-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>
Signed-off-by: Xianglai Li <lixianglai@xxxxxxxxxxx>
---
Cc: Bibo Mao <maobibo@xxxxxxxxxxx>
Cc: Huacai Chen <chenhuacai@xxxxxxxxxx>
Cc: kvm@xxxxxxxxxxxxxxx
Cc: loongarch@xxxxxxxxxxxxxxx
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>
Cc: WANG Xuerui <kernel@xxxxxxxxxx>
Cc: Xianglai li <lixianglai@xxxxxxxxxxx>

arch/loongarch/include/asm/kvm_host.h | 2 +
arch/loongarch/include/asm/kvm_ipi.h | 16 ++
arch/loongarch/kvm/intc/ipi.c | 292 +++++++++++++++++++++++++-
3 files changed, 307 insertions(+), 3 deletions(-)

diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h
index 2b65007503dc..7c89e26c23c3 100644
--- a/arch/loongarch/include/asm/kvm_host.h
+++ b/arch/loongarch/include/asm/kvm_host.h
@@ -44,6 +44,8 @@ struct kvm_vm_stat {
struct kvm_vm_stat_generic generic;
u64 pages;
u64 hugepages;
+ u64 ipi_read_exits;
+ u64 ipi_write_exits;
};

struct kvm_vcpu_stat {
diff --git a/arch/loongarch/include/asm/kvm_ipi.h b/arch/loongarch/include/asm/kvm_ipi.h
index 3dacdf1781b8..ce10554fb502 100644
--- a/arch/loongarch/include/asm/kvm_ipi.h
+++ b/arch/loongarch/include/asm/kvm_ipi.h
@@ -29,8 +29,24 @@ struct ipi_state {
#define SMP_MAILBOX 0x1000
#define KVM_IOCSR_IPI_ADDR_SIZE 0x48

+#define CORE_STATUS_OFF 0x000
+#define CORE_EN_OFF 0x004
+#define CORE_SET_OFF 0x008
+#define CORE_CLEAR_OFF 0x00c
+#define CORE_BUF_20 0x020
+#define CORE_BUF_28 0x028
+#define CORE_BUF_30 0x030
+#define CORE_BUF_38 0x038
+#define IOCSR_IPI_SEND 0x040
+
+#define IOCSR_MAIL_SEND 0x048
+#define IOCSR_ANY_SEND 0x158
+
#define MAIL_SEND_ADDR (SMP_MAILBOX + IOCSR_MAIL_SEND)
#define KVM_IOCSR_MAIL_ADDR_SIZE 0x118

+#define MAIL_SEND_OFFSET 0
+#define ANY_SEND_OFFSET (IOCSR_ANY_SEND - IOCSR_MAIL_SEND)
+
int kvm_loongarch_register_ipi_device(void);
#endif
diff --git a/arch/loongarch/kvm/intc/ipi.c b/arch/loongarch/kvm/intc/ipi.c
index 5a19712185d5..2620c1500078 100644
--- a/arch/loongarch/kvm/intc/ipi.c
+++ b/arch/loongarch/kvm/intc/ipi.c
@@ -7,25 +7,311 @@
#include <asm/kvm_ipi.h>
#include <asm/kvm_vcpu.h>

+static void ipi_send(struct kvm *kvm, uint64_t data)
+{
+ struct kvm_vcpu *vcpu;
+ struct kvm_interrupt irq;
+ int cpu, action, status;
+
+ cpu = ((data & 0xffffffff) >> 16) & 0x3ff;
+ vcpu = kvm_get_vcpu_by_cpuid(kvm, cpu);
+ if (unlikely(vcpu == NULL)) {
+ kvm_err("%s: invalid target cpu: %d\n", __func__, cpu);
+ return;
+ }
+
+ action = BIT(data & 0x1f);
+ spin_lock(&vcpu->arch.ipi_state.lock);
+ status = vcpu->arch.ipi_state.status;
+ vcpu->arch.ipi_state.status |= action;
+ spin_unlock(&vcpu->arch.ipi_state.lock);
+ if (status == 0) {
+ irq.irq = LARCH_INT_IPI;
+ kvm_vcpu_ioctl_interrupt(vcpu, &irq);
+ }
+}
+
+static void ipi_clear(struct kvm_vcpu *vcpu, uint64_t data)
+{
+ struct kvm_interrupt irq;
+ uint32_t status;
+
+ spin_lock(&vcpu->arch.ipi_state.lock);
+ vcpu->arch.ipi_state.status &= ~data;
+ status = vcpu->arch.ipi_state.status;
+ spin_unlock(&vcpu->arch.ipi_state.lock);
+ if (!status) {
+ irq.irq = -LARCH_INT_IPI;
+ kvm_vcpu_ioctl_interrupt(vcpu, &irq);
+ }
+}
+
+static uint64_t read_mailbox(struct kvm_vcpu *vcpu, int offset, int len)
+{
+ uint64_t ret = 0;
+ uint64_t data = 0;
+
+ spin_lock(&vcpu->arch.ipi_state.lock);
+ data = *(ulong *)((void *)vcpu->arch.ipi_state.buf + (offset - 0x20));
+ spin_unlock(&vcpu->arch.ipi_state.lock);
+
+ if (len == 1)
+ ret = data & 0xff;
+ else if (len == 2)
+ ret = data & 0xffff;
+ else if (len == 4)
+ ret = data & 0xffffffff;
+ else if (len == 8)
+ ret = data;
+ else
+ kvm_err("%s: unknown data len: %d\n", __func__, len);
+ return ret;
+}
+
+static void write_mailbox(struct kvm_vcpu *vcpu, int offset,
+ uint64_t data, int len)
+{
+ void *pbuf;
+ bool bad_width = false;
+
+ spin_lock(&vcpu->arch.ipi_state.lock);
+ pbuf = (void *)vcpu->arch.ipi_state.buf + (offset - 0x20);
+ if (len == 1)
+ *(unsigned char *)pbuf = (unsigned char)data;
+ else if (len == 2)
+ *(unsigned short *)pbuf = (unsigned short)data;
+ else if (len == 4)
+ *(unsigned int *)pbuf = (unsigned int)data;
+ else if (len == 8)
+ *(unsigned long *)pbuf = (unsigned long)data;
+ else
+ bad_width = true;
+ spin_unlock(&vcpu->arch.ipi_state.lock);
+ if (bad_width)
+ kvm_err("%s: unknown data len: %d\n", __func__, len);
+}
+
+static int loongarch_ipi_writel(struct kvm_vcpu *vcpu, gpa_t addr,
+ int len, const void *val)
+{
+ uint64_t data;
+ uint32_t offset;
+ int ret = 0;
+
+ data = *(uint64_t *)val;
+
+ offset = (uint32_t)(addr & 0xff);
+ WARN_ON_ONCE(offset & (len - 1));
+
+ switch (offset) {
+ case CORE_STATUS_OFF:
+ kvm_err("CORE_SET_OFF Can't be write\n");
+ ret = -EINVAL;
+ break;
+ case CORE_EN_OFF:
+ spin_lock(&vcpu->arch.ipi_state.lock);
+ vcpu->arch.ipi_state.en = data;
+ spin_unlock(&vcpu->arch.ipi_state.lock);
+ break;
+ case IOCSR_IPI_SEND:
+ ipi_send(vcpu->kvm, data);
+ break;
+ case CORE_SET_OFF:
+ ret = -EINVAL;
+ break;
+ case CORE_CLEAR_OFF:
+ /* Just clear the status of the current vcpu */
+ ipi_clear(vcpu, data);
+ break;
+ case CORE_BUF_20 ... CORE_BUF_38 + 7:
+ if (offset + len > CORE_BUF_38 + 8) {
+ kvm_err("%s: invalid offset or len: offset = %d, len = %d\n",
+ __func__, offset, len);
+ ret = -EINVAL;
+ break;
+ }
+ write_mailbox(vcpu, offset, data, len);
+ break;
+ default:
+ kvm_err("%s: unknown addr: %llx\n", __func__, addr);
+ ret = -EINVAL;
+ break;
+ }
+ return ret;
+}
+
+static int loongarch_ipi_readl(struct kvm_vcpu *vcpu, gpa_t addr,
+ int len, void *val)
+{
+ uint32_t offset;
+ uint64_t res = 0;
+ int ret = 0;
+
+ offset = (uint32_t)(addr & 0xff);
+ WARN_ON_ONCE(offset & (len - 1));
+
+ switch (offset) {
+ case CORE_STATUS_OFF:
+ spin_lock(&vcpu->arch.ipi_state.lock);
+ res = vcpu->arch.ipi_state.status;
+ spin_unlock(&vcpu->arch.ipi_state.lock);
+ break;
+ case CORE_EN_OFF:
+ spin_lock(&vcpu->arch.ipi_state.lock);
+ res = vcpu->arch.ipi_state.en;
+ spin_unlock(&vcpu->arch.ipi_state.lock);
+ break;
+ case CORE_SET_OFF:
+ res = 0;
+ break;
+ case CORE_CLEAR_OFF:
+ res = 0;
+ break;
+ case CORE_BUF_20 ... CORE_BUF_38 + 7:
+ if (offset + len > CORE_BUF_38 + 8) {
+ kvm_err("%s: invalid offset or len: offset = %d, len = %d\n",
+ __func__, offset, len);
+ ret = -EINVAL;
+ break;
+ }
+ res = read_mailbox(vcpu, offset, len);
+ break;
+ default:
+ kvm_err("%s: unknown addr: %llx\n", __func__, addr);
+ ret = -EINVAL;
+ break;
+ }
+ *(uint64_t *)val = res;
+ return ret;
+}
+
static int kvm_ipi_write(struct kvm_vcpu *vcpu,
struct kvm_io_device *dev,
gpa_t addr, int len, const void *val)
{
- return 0;
+ struct loongarch_ipi *ipi;
+ int ret;
+
+ ipi = vcpu->kvm->arch.ipi;
+ if (!ipi) {
+ kvm_err("%s: ipi irqchip not valid!\n", __func__);
+ return -EINVAL;
+ }
+ ipi->kvm->stat.ipi_write_exits++;
+ ret = loongarch_ipi_writel(vcpu, addr, len, val);
+ return ret;
}

static int kvm_ipi_read(struct kvm_vcpu *vcpu,
struct kvm_io_device *dev,
gpa_t addr, int len, void *val)
{
- return 0;
+ struct loongarch_ipi *ipi;
+ int ret;
+
+ ipi = vcpu->kvm->arch.ipi;
+ if (!ipi) {
+ kvm_err("%s: ipi irqchip not valid!\n", __func__);
+ return -EINVAL;
+ }
+ ipi->kvm->stat.ipi_read_exits++;
+ ret = loongarch_ipi_readl(vcpu, addr, len, val);
+ return ret;
+}
+
+static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data)
+{
+ int i, ret;
+ uint32_t val = 0, mask = 0;
+ /*
+ * Bit 27-30 is mask for byte writing.
+ * If the mask is 0, we need not to do anything.
+ */
+ if ((data >> 27) & 0xf) {
+ /* Read the old val */
+ ret = kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, sizeof(val), &val);
+ if (unlikely(ret)) {
+ kvm_err("%s: : read date from addr %llx failed\n", __func__, addr);
+ return ret;
+ }
+ /* Construct the mask by scanning the bit 27-30 */
+ for (i = 0; i < 4; i++) {
+ if (data & (BIT(27 + i)))
+ mask |= (0xff << (i * 8));
+ }
+ /* Save the old part of val */
+ val &= mask;
+ }
+ val |= ((uint32_t)(data >> 32) & ~mask);
+ ret = kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, sizeof(val), &val);
+ if (unlikely(ret))
+ kvm_err("%s: : write date to addr %llx failed\n", __func__, addr);
+ return ret;
+}
+
+static int mail_send(struct kvm *kvm, uint64_t data)
+{
+ struct kvm_vcpu *vcpu;
+ int cpu, mailbox;
+ int offset, ret;
+
+ cpu = ((data & 0xffffffff) >> 16) & 0x3ff;
+ vcpu = kvm_get_vcpu_by_cpuid(kvm, cpu);
+ if (unlikely(vcpu == NULL)) {
+ kvm_err("%s: invalid target cpu: %d\n", __func__, cpu);
+ return -EINVAL;
+ }
+ mailbox = ((data & 0xffffffff) >> 2) & 0x7;
+ offset = SMP_MAILBOX + CORE_BUF_20 + mailbox * 4;
+ ret = send_ipi_data(vcpu, offset, data);
+ return ret;
+}
+
+static int any_send(struct kvm *kvm, uint64_t data)
+{
+ struct kvm_vcpu *vcpu;
+ int cpu, offset, ret;
+
+ cpu = ((data & 0xffffffff) >> 16) & 0x3ff;
+ vcpu = kvm_get_vcpu_by_cpuid(kvm, cpu);
+ if (unlikely(vcpu == NULL)) {
+ kvm_err("%s: invalid target cpu: %d\n", __func__, cpu);
+ return -EINVAL;
+ }
+ offset = data & 0xffff;
+ ret = send_ipi_data(vcpu, offset, data);
+ return ret;
}

static int kvm_loongarch_mail_write(struct kvm_vcpu *vcpu,
struct kvm_io_device *dev,
gpa_t addr, int len, const void *val)
{
- return 0;
+ struct loongarch_ipi *ipi;
+ int ret;
+
+ ipi = vcpu->kvm->arch.ipi;
+ if (!ipi) {
+ kvm_err("%s: ipi irqchip not valid!\n", __func__);
+ return -EINVAL;
+ }
+
+ addr &= 0xfff;
+ addr -= IOCSR_MAIL_SEND;
+
+ switch (addr) {
+ case MAIL_SEND_OFFSET:
+ ret = mail_send(vcpu->kvm, *(uint64_t *)val);
+ break;
+ case ANY_SEND_OFFSET:
+ ret = any_send(vcpu->kvm, *(uint64_t *)val);
+ break;
+ default:
+ kvm_err("%s: invalid addr %llx!\n", __func__, addr);
+ ret = -EINVAL;
+ break;
+ }
+ return ret;
}

static const struct kvm_io_device_ops kvm_ipi_ops = {
--
2.39.1