On Tue, Aug 20, 2024 at 12:02 PM maobibo <maobibo@xxxxxxxxxxx> wrote:
>
> Huacai,
>
> On 2024/8/19 下午9:34, Huacai Chen wrote:
> > Hi, Bibo,
> >
> > On Mon, Aug 12, 2024 at 11:02 AM Bibo Mao <maobibo@xxxxxxxxxxx> wrote:
> >>
> >> Interrupts can be routed to maximal four virtual CPUs with one HW
> >> EIOINTC interrupt controller model, since interrupt routing is encoded with
> >> CPU bitmap and EIOINTC node combined method. Here add the EIOINTC virt
> >> extension support so that interrupts can be routed to 256 vCPUs on
> >> hypervisor mode. CPU bitmap is replaced with normal encoding and EIOINTC
> >> node type is removed, so there are 8 bits for cpu selection, at most 256
> >> vCPUs are supported for interrupt routing.
> >>
> >> Co-developed-by: Song Gao <gaosong@xxxxxxxxxxx>
> >> Signed-off-by: Song Gao <gaosong@xxxxxxxxxxx>
> >> Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>
> >> ---
> >> .../arch/loongarch/irq-chip-model.rst | 64 ++++++++++
> >> .../zh_CN/arch/loongarch/irq-chip-model.rst | 55 +++++++++
> >> arch/loongarch/include/asm/irq.h | 1 +
> >> drivers/irqchip/irq-loongson-eiointc.c | 109 ++++++++++++++----
> >> 4 files changed, 209 insertions(+), 20 deletions(-)
> >>
> >> diff --git a/Documentation/arch/loongarch/irq-chip-model.rst b/Documentation/arch/loongarch/irq-chip-model.rst
> >> index 7988f4192363..d2350780ad1d 100644
> >> --- a/Documentation/arch/loongarch/irq-chip-model.rst
> >> +++ b/Documentation/arch/loongarch/irq-chip-model.rst
> >> @@ -85,6 +85,70 @@ to CPUINTC directly::
> >> | Devices |
> >> +---------+
> >>
> >> +Virtual extended IRQ model
> >> +==========================
> >> +
> >> +In this model, IPI (Inter-Processor Interrupt) and CPU Local Timer interrupt
> >> +go to CPUINTC directly, CPU UARTS interrupts go to PCH-PIC, while all other
> >> +devices interrupts go to PCH-PIC/PCH-MSI and gathered by V-EIOINTC (Virtual
> >> +Extended I/O Interrupt Controller), and then go to CPUINTC directly::
> >> +
> >> + +-----+ +-------------------+ +-------+
> >> + | IPI |--> | CPUINTC(0-255vcpu)| <-- | Timer |
> >> + +-----+ +-------------------+ +-------+
> >> + ^
> >> + |
> >> + +-----------+
> >> + | V-EIOINTC |
> >> + +-----------+
> >> + ^ ^
> >> + | |
> >> + +---------+ +---------+
> >> + | PCH-PIC | | PCH-MSI |
> >> + +---------+ +---------+
> >> + ^ ^ ^
> >> + | | |
> >> + +--------+ +---------+ +---------+
> >> + | UARTs | | Devices | | Devices |
> >> + +--------+ +---------+ +---------+
> >> +
> >> +
> >> +Description
> >> +-----------
> >> +V-EIOINTC (Virtual Extended I/O Interrupt Controller) is an extension of
> >> +EIOINTC, it only works in VM mode which runs in KVM hypervisor. Interrupts can
> >> +be routed to up to four vCPUs via standard EIOINTC, however with V-EIOINTC
> >> +interrupts can be routed to up to 256 virtual cpus.
> >> +
> >> +With standard EIOINTC, interrupt routing setting includes two parts: eight
> >> +bits for CPU selection and four bits for CPU IP (Interrupt Pin) selection.
> >> +For CPU selection there is four bits for EIOINTC node selection, four bits
> >> +for EIOINTC CPU selection. Bitmap method is used for CPU selection and
> >> +CPU IP selection, so interrupt can only route to CPU0 - CPU3 and IP0-IP3 in
> >> +one EIOINTC node.
> >> +
> >> +With V-EIOINTC it supports to route more CPUs and CPU IP (Interrupt Pin),
> >> +there are two newly added registers with V-EIOINTC.
> >> +
> >> +EXTIOI_VIRT_FEATURES
> >> +--------------------
> >> +This register is read-only register, which indicates supported features with
> >> +V-EIOINTC. Feature EXTIOI_HAS_INT_ENCODE and EXTIOI_HAS_CPU_ENCODE is added.
> >> +
> >> +Feature EXTIOI_HAS_INT_ENCODE is part of standard EIOINTC. If it is 1, it
> >> +indicates that CPU Interrupt Pin selection can be normal method rather than
> >> +bitmap method, so interrupt can be routed to IP0 - IP15.
> >> +
> >> +Feature EXTIOI_HAS_CPU_ENCODE is entension of V-EIOINTC. If it is 1, it
> >> +indicates that CPU selection can be normal method rather than bitmap method,
> >> +so interrupt can be routed to CPU0 - CPU255.
> >> +
> >> +EXTIOI_VIRT_CONFIG
> >> +------------------
> >> +This register is read-write register, for compatibility intterupt routed uses
> >> +the default method which is the same with standard EIOINTC. If the bit is set
> >> +with 1, it indicated HW to use normal method rather than bitmap method.
> >> +
> >> ACPI-related definitions
> >> ========================
> >>
> >> diff --git a/Documentation/translations/zh_CN/arch/loongarch/irq-chip-model.rst b/Documentation/translations/zh_CN/arch/loongarch/irq-chip-model.rst
> >> index f1e9ab18206c..d696bd394c02 100644
> >> --- a/Documentation/translations/zh_CN/arch/loongarch/irq-chip-model.rst
> >> +++ b/Documentation/translations/zh_CN/arch/loongarch/irq-chip-model.rst
> >> @@ -87,6 +87,61 @@ PCH-LPC/PCH-MSI，然后被EIOINTC统一收集，再直接到达CPUINTC::
> >> | Devices |
> >> +---------+
> >>
> >> +虚拟扩展IRQ模型
> >> +===============
> >> +
> >> +在这种模型里面, IPI(Inter-Processor Interrupt) 和CPU本地时钟中断直接发送到CPUINTC,
> >> +CPU串口 (UARTs) 中断发送到PCH-PIC, 而其他所有设备的中断则分别发送到所连接的PCH_PIC/
> >> +PCH-MSI, 然后V-EIOINTC统一收集，再直接到达CPUINTC::
> >> +
> >> + +-----+ +-------------------+ +-------+
> >> + | IPI |--> | CPUINTC(0-255vcpu)| <-- | Timer |
> >> + +-----+ +-------------------+ +-------+
> >> + ^
> >> + |
> >> + +-----------+
> >> + | V-EIOINTC |
> >> + +-----------+
> >> + ^ ^
> >> + | |
> >> + +---------+ +---------+
> >> + | PCH-PIC | | PCH-MSI |
> >> + +---------+ +---------+
> >> + ^ ^ ^
> >> + | | |
> >> + +--------+ +---------+ +---------+
> >> + | UARTs | | Devices | | Devices |
> >> + +--------+ +---------+ +---------+
> >> +
> >> +V-EIOINTC 是EIOINTC的扩展, 仅工作在hyperisor模式下, 中断经EIOINTC最多可个路由到４个
> >> +虚拟cpu. 但中断经V-EIOINTC最多可个路由到256个虚拟cpu.
> >> +
> >> +传统的EIOINTC中断控制器，中断路由分为两个部分：8比特用于控制路由到哪个CPU，
> >> +4比特用于控制路由到特定CPU的哪个中断管脚.控制CPU路由的8比特前4比特用于控制
> >> +路由到哪个EIOINTC节点，后4比特用于控制此节点哪个CPU。中断路由在选择CPU路由
> >> +和CPU中断管脚路由时，使用bitmap编码方式而不是正常编码方式，所以对于一个
> >> +EIOINTC中断控制器节点，中断只能路由到CPU0 - CPU3，中断管教IP0-IP3。
> >> +
> >> +V-EIOINTC新增了两个寄存器，支持中断路由到更多CPU个和中断管脚。
> >> +
> >> +V-EIOINTC功能寄存器
> >> +-------------------
> >> +功能寄存器是只读寄存器，用于显示V-EIOINTC支持的特性，目前两个支持两个特性
> >> +EXTIOI_HAS_INT_ENCODE 和 EXTIOI_HAS_CPU_ENCODE。
> >> +
> >> +特性EXTIOI_HAS_INT_ENCODE是传统EIOINTC中断控制器的一个特性，如果此比特为1，
> >> +显示CPU中断管脚路由方式支持正常编码，而不是bitmap编码，所以中断可以路由到
> >> +管脚IP0 - IP15。
> >> +
> >> +特性EXTIOI_HAS_CPU_ENCODE是V-EIOINTC新增特性，如果此比特为1，表示CPU路由
> >> +方式支持正常编码，而不是bitmap编码，所以中断可以路由到CPU0 - CPU255。
> >> +
> >> +V-EIOINTC配置寄存器
> >> +-------------------
> >> +配置寄存器是可读写寄存器，为了兼容性考虑，如果不写此寄存器，中断路由采用
> >> +和传统EIOINTC相同的路由设置。如果对应比特设置为1，表示采用正常路由方式而
> >> +不是bitmap编码的路由方式。
> >> +
> >> ACPI相关的定义
> >> ==============
> >>
> >> diff --git a/arch/loongarch/include/asm/irq.h b/arch/loongarch/include/asm/irq.h
> >> index 480418bc5071..ce85d4c7d225 100644
> >> --- a/arch/loongarch/include/asm/irq.h
> >> +++ b/arch/loongarch/include/asm/irq.h
> >> @@ -54,6 +54,7 @@ extern struct acpi_vector_group pch_group[MAX_IO_PICS];
> >> extern struct acpi_vector_group msi_group[MAX_IO_PICS];
> >>
> >> #define CORES_PER_EIO_NODE 4
> >> +#define CORES_PER_VEIO_NODE 256
> >>
> >> #define LOONGSON_CPU_UART0_VEC 10 /* CPU UART0 */
> >> #define LOONGSON_CPU_THSENS_VEC 14 /* CPU Thsens */
> >> diff --git a/drivers/irqchip/irq-loongson-eiointc.c b/drivers/irqchip/irq-loongson-eiointc.c
> >> index b1f2080be2be..cc5b1ec13531 100644
> >> --- a/drivers/irqchip/irq-loongson-eiointc.c
> >> +++ b/drivers/irqchip/irq-loongson-eiointc.c
> >> @@ -14,6 +14,7 @@
> >> #include <linux/irqdomain.h>
> >> #include <linux/irqchip/chained_irq.h>
> >> #include <linux/kernel.h>
> >> +#include <linux/kvm_para.h>
> >> #include <linux/syscore_ops.h>
> >> #include <asm/numa.h>
> >>
> >> @@ -24,15 +25,36 @@
> >> #define EIOINTC_REG_ISR 0x1800
> >> #define EIOINTC_REG_ROUTE 0x1c00
> >>
> >> +#define EXTIOI_VIRT_FEATURES 0x40000000
> >> +#define EXTIOI_HAS_VIRT_EXTENSION BIT(0)
> >> +#define EXTIOI_HAS_ENABLE_OPTION BIT(1)
> >> +#define EXTIOI_HAS_INT_ENCODE BIT(2)
> >> +#define EXTIOI_HAS_CPU_ENCODE BIT(3)
> >> +#define EXTIOI_VIRT_CONFIG 0x40000004
> >> +#define EXTIOI_ENABLE BIT(1)
> >> +#define EXTIOI_ENABLE_INT_ENCODE BIT(2)
> >> +#define EXTIOI_ENABLE_CPU_ENCODE BIT(3)
> > After careful reading, I found the only used bits are
> > EXTIOI_HAS_CPU_ENCODE/EXTIOI_ENABLE_CPU_ENCODE. So to minimize the
> EXTIOI_HAS_INT_ENCODE/EXTIOI_ENABLE_INT_ENCODE can be used also,
> EXTIOI_HAS_INT_ENCODE is encoding method to route irq to CPU Interrupt
> Pin. With bitmap method, it can only be routed to IP0-IP3; with normal
> method it can be routed to IP0-IP15 at most.
>
> And the real HW supports this method, only that EIOINTC driver does not
> use it.
>
> > complexity, I suggest to define virtual register as below:
> > #define EXTIOI_VIRT_FEATURES 0x40000000
> > #define EXTIOI_HAS_VIRT_EXTENSION BIT(0)
> > #define EXTIOI_ENABLE_CPU_ENCODE BIT(15)
> > Then only one register, the low 16 bits are indicators while the high
> > 16 bits are enable controls. Even if we will extend more (hardly
> > happen, I think), there is enough spaces.
> Two registers is better from my view, otherwise lower 16 bit is readonly
> and higher 16 bit is writable. one is read-only indicating the supported
> features and the other is writable. That is easy to use for device
> drivers and emulation in qemu.
Then we can still reduce complexity like this:
+#define EXTIOI_VIRT_FEATS 0x40000000
+#define EXTIOI_HAS_INT_ENCODE BIT(0)
+#define EXTIOI_HAS_CPU_ENCODE BIT(1)
+#define EXTIOI_VIRT_CONFIG 0x40000004
+#define EXTIOI_ENABLE_INT_ENCODE BIT(0)
+#define EXTIOI_ENABLE_CPU_ENCODE BIT(1)
EXTIOI_HAS_VIRT_EXTENSION looks like a parent indicator for
INT_ENCODE/CPU_ENCODE, but useless.
Huacai
> >
> >> +
> >> #define VEC_REG_COUNT 4
> >> #define VEC_COUNT_PER_REG 64
> >> #define VEC_COUNT (VEC_REG_COUNT * VEC_COUNT_PER_REG)
> >> #define VEC_REG_IDX(irq_id) ((irq_id) / VEC_COUNT_PER_REG)
> >> #define VEC_REG_BIT(irq_id) ((irq_id) % VEC_COUNT_PER_REG)
> >> #define EIOINTC_ALL_ENABLE 0xffffffff
> >> +#define EIOINTC_ALL_ENABLE_VEC_MASK(vector) (EIOINTC_ALL_ENABLE & ~BIT(vector & 0x1F))
> >> +#define EIOINTC_REG_ENABLE_VEC(vector) (EIOINTC_REG_ENABLE + ((vector >> 5) << 2))
> >>
> >> #define MAX_EIO_NODES (NR_CPUS / CORES_PER_EIO_NODE)
> >>
> >> +/*
> >> + * Routing registers are 32bit, and there is 8-bit route setting for every
> >> + * interrupt vector. So one Route register contains four vectors routing
> >> + * information.
> >> + */
> >> +#define EIOINTC_REG_ROUTE_VEC(vector) (EIOINTC_REG_ROUTE + (vector & ~0x03))
> >> +#define EIOINTC_REG_ROUTE_VEC_SHIFT(vector) ((vector & 0x03) << 3)
> >> +#define EIOINTC_REG_ROUTE_VEC_MASK(vector) (0xff << EIOINTC_REG_ROUTE_VEC_SHIFT(vector))
> >> +
> >> static int nr_pics;
> >>
> >> struct eiointc_priv {
> >> @@ -42,6 +64,7 @@ struct eiointc_priv {
> >> cpumask_t cpuspan_map;
> >> struct fwnode_handle *domain_handle;
> >> struct irq_domain *eiointc_domain;
> >> + bool cpu_encoded;
> >> };
> >>
> >> static struct eiointc_priv *eiointc_priv[MAX_IO_PICS];
> >> @@ -57,7 +80,13 @@ static void eiointc_enable(void)
> >>
> >> static int cpu_to_eio_node(int cpu)
> >> {
> >> - return cpu_logical_map(cpu) / CORES_PER_EIO_NODE;
> >> + int cores;
> >> +
> >> + if (kvm_para_has_feature(KVM_FEATURE_VIRT_EXTIOI))
> >> + cores = CORES_PER_VEIO_NODE;
> >> + else
> >> + cores = CORES_PER_EIO_NODE;
> >> + return cpu_logical_map(cpu) / cores;
> >> }
> >>
> >> #ifdef CONFIG_SMP
> >> @@ -89,6 +118,16 @@ static void eiointc_set_irq_route(int pos, unsigned int cpu, unsigned int mnode,
> >>
> >> static DEFINE_RAW_SPINLOCK(affinity_lock);
> >>
> >> +static void virt_extioi_set_irq_route(unsigned int vector, unsigned int cpu)
> >> +{
> >> + unsigned long reg = EIOINTC_REG_ROUTE_VEC(vector);
> >> + u32 data = iocsr_read32(reg);
> >> +
> >> + data &= ~EIOINTC_REG_ROUTE_VEC_MASK(vector);
> >> + data |= cpu_logical_map(cpu) << EIOINTC_REG_ROUTE_VEC_SHIFT(vector);
> >> + iocsr_write32(data, reg);
> >> +}
> > This function can be embedded into eiointc_set_irq_affinity().
> With optimization compiler, it will inline instead. I prefer to put this
> separated so that it can show difference.
>
> To be frankly, the origin driver about irq affinity setting is hard to
> review and understand, I do not want to mix with it together. Here is
> piece of code about irq affinity setting in origin driver.
>
> > /* Mask target vector */
> > csr_any_send(regaddr, EIOINTC_ALL_ENABLE_VEC_MASK(vector),
> > 0x0, priv->node * CORES_PER_EIO_NODE);
> > /* Set route for target vector */
> > eiointc_set_irq_route(vector, cpu, priv->node, &priv->node_map);
> > /* Unmask target vector */
> > csr_any_send(regaddr, EIOINTC_ALL_ENABLE, 0x0, priv->node *
> CORES_PER_EIO_NODE);
>
> Can people understand why csr_any_send() is used here?
>
> > for_each_online_cpu(i) {
> > node = cpu_to_eio_node(i);
> > if (!node_isset(node, *node_map))
> > continue;
> > /* EIO node 0 is in charge of inter-node interrupt dispatch */
> > route_node = (node == mnode) ? cpu_node : node;
> > data = ((coremap | (route_node << 4)) << (data_byte * 8));
> > csr_any_send(EIOINTC_REG_ROUTE + pos_off, data, data_mask,
> node * CORES_PER_EIO_NODE);
> Why is there csr_any_send() for every online cpu? It will cause almost
> every cpu calling csr_any_send() when setting irq affinity.
>
> >
> >> +
> >> static int eiointc_set_irq_affinity(struct irq_data *d, const struct cpumask *affinity, bool force)
> >> {
> >> unsigned int cpu;
> >> @@ -105,18 +144,24 @@ static int eiointc_set_irq_affinity(struct irq_data *d, const struct cpumask *af
> >> }
> >>
> >> vector = d->hwirq;
> >> - regaddr = EIOINTC_REG_ENABLE + ((vector >> 5) << 2);
> >> -
> >> - /* Mask target vector */
> >> - csr_any_send(regaddr, EIOINTC_ALL_ENABLE & (~BIT(vector & 0x1F)),
> >> - 0x0, priv->node * CORES_PER_EIO_NODE);
> >> -
> >> - /* Set route for target vector */
> >> - eiointc_set_irq_route(vector, cpu, priv->node, &priv->node_map);
> >> -
> >> - /* Unmask target vector */
> >> - csr_any_send(regaddr, EIOINTC_ALL_ENABLE,
> >> - 0x0, priv->node * CORES_PER_EIO_NODE);
> >> + regaddr = EIOINTC_REG_ENABLE_VEC(vector);
> >> +
> >> + if (priv->cpu_encoded) {
> >> + iocsr_write32(EIOINTC_ALL_ENABLE_VEC_MASK(vector), regaddr);
> >> + virt_extioi_set_irq_route(vector, cpu);
> >> + iocsr_write32(EIOINTC_ALL_ENABLE, regaddr);
> >> + } else {
> >> + /* Mask target vector */
> >> + csr_any_send(regaddr, EIOINTC_ALL_ENABLE_VEC_MASK(vector),
> >> + 0x0, priv->node * CORES_PER_EIO_NODE);
> >> +
> >> + /* Set route for target vector */
> >> + eiointc_set_irq_route(vector, cpu, priv->node, &priv->node_map);
> >> +
> >> + /* Unmask target vector */
> >> + csr_any_send(regaddr, EIOINTC_ALL_ENABLE,
> >> + 0x0, priv->node * CORES_PER_EIO_NODE);
> >> + }
> >>
> >> irq_data_update_effective_affinity(d, cpumask_of(cpu));
> >>
> >> @@ -140,17 +185,23 @@ static int eiointc_index(int node)
> >>
> >> static int eiointc_router_init(unsigned int cpu)
> >> {
> >> - int i, bit;
> >> - uint32_t data;
> >> - uint32_t node = cpu_to_eio_node(cpu);
> >> - int index = eiointc_index(node);
> >> + int i, bit, cores, index, node;
> >> + unsigned int data;
> >> +
> >> + node = cpu_to_eio_node(cpu);
> >> + index = eiointc_index(node);
> >>
> >> if (index < 0) {
> >> pr_err("Error: invalid nodemap!\n");
> >> - return -1;
> >> + return -EINVAL;
> >> }
> >>
> >> - if ((cpu_logical_map(cpu) % CORES_PER_EIO_NODE) == 0) {
> >> + if (eiointc_priv[index]->cpu_encoded)
> >> + cores = CORES_PER_VEIO_NODE;
> >> + else
> >> + cores = CORES_PER_EIO_NODE;
> >> +
> >> + if ((cpu_logical_map(cpu) % cores) == 0) {
> >> eiointc_enable();
> >>
> >> for (i = 0; i < eiointc_priv[0]->vec_count / 32; i++) {
> >> @@ -166,7 +217,9 @@ static int eiointc_router_init(unsigned int cpu)
> >>
> >> for (i = 0; i < eiointc_priv[0]->vec_count / 4; i++) {
> >> /* Route to Node-0 Core-0 */
> >> - if (index == 0)
> >> + if (eiointc_priv[index]->cpu_encoded)
> >> + bit = cpu_logical_map(0);
> >> + else if (index == 0)
> >> bit = BIT(cpu_logical_map(0));
> >> else
> >> bit = (eiointc_priv[index]->node << 4) | 1;
> >> @@ -367,6 +420,19 @@ static int __init acpi_cascade_irqdomain_init(void)
> >> return 0;
> >> }
> >>
> >> +static void __init kvm_eiointc_init(struct eiointc_priv *priv)
> >> +{
> >> + int val;
> >> +
> >> + val = iocsr_read32(EXTIOI_VIRT_FEATURES);
> >> + if (val & EXTIOI_HAS_CPU_ENCODE) {
> >> + val = iocsr_read32(EXTIOI_VIRT_CONFIG);
> >> + val |= EXTIOI_ENABLE_CPU_ENCODE;
> >> + iocsr_write32(val, EXTIOI_VIRT_CONFIG);
> >> + priv->cpu_encoded = true;
> >> + }
> >> +}
> > This function can be embedded into eiointc_init().
> Both method is ok for me, maybe embedded method is better.
> Will do in next patch.
>
> Regards
> Bibo Mao
> >
> > Huacai
> >
> >> +
> >> static int __init eiointc_init(struct eiointc_priv *priv, int parent_irq,
> >> u64 node_map)
> >> {
> >> @@ -390,6 +456,9 @@ static int __init eiointc_init(struct eiointc_priv *priv, int parent_irq,
> >> return -ENOMEM;
> >> }
> >>
> >> + if (kvm_para_has_feature(KVM_FEATURE_VIRT_EXTIOI))
> >> + kvm_eiointc_init(priv);
> >> +
> >> eiointc_priv[nr_pics++] = priv;
> >> eiointc_router_init(0);
> >> irq_set_chained_handler_and_data(parent_irq, eiointc_irq_dispatch, priv);
> >> --
> >> 2.39.3
> >>
>
>
