[PATCH v2 7/8] arm: add support for supplying GICv3 redistributor addresses
Andre Przywara
andre.przywara at arm.com
Mon Jun 15 04:12:48 PDT 2015
On 06/10/2015 06:40 PM, Marc Zyngier wrote:
> On 05/06/15 09:37, Andre Przywara wrote:
>> The code currently is assuming fixed sized memory regions for the
>> distributor and CPU interface. GICv3 needs a dynamic allocation of
>> its redistributor region, since its size depends on the number of
>> vCPUs.
>> Also add the necessary code to create a GICv3 IRQ chip instance.
>> This contains some defines which are not (yet) in the (32 bit) header
>> files to allow compilation for ARM.
>>
>> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
>> ---
>> arm/gic.c | 37 +++++++++++++++++++++++++++++++++++--
>> arm/include/arm-common/gic.h | 2 +-
>> arm/include/arm-common/kvm-arch.h | 18 ++++++++++++++----
>> arm/kvm-cpu.c | 4 +++-
>> 4 files changed, 53 insertions(+), 8 deletions(-)
>>
>> diff --git a/arm/gic.c b/arm/gic.c
>> index 0ce40e4..c50d662 100644
>> --- a/arm/gic.c
>> +++ b/arm/gic.c
>> @@ -9,13 +9,24 @@
>> #include <linux/kernel.h>
>> #include <linux/kvm.h>
>>
>> +/* Those names are not defined for ARM (yet) */
>> +#ifndef KVM_VGIC_V3_ADDR_TYPE_DIST
>> +#define KVM_VGIC_V3_ADDR_TYPE_DIST 2
>> +#endif
>> +
>> +#ifndef KVM_VGIC_V3_ADDR_TYPE_REDIST
>> +#define KVM_VGIC_V3_ADDR_TYPE_REDIST 3
>> +#endif
>> +
>> static int gic_fd = -1;
>> +static int nr_redists;
>
> Who sets this variable?
>>
>> static int gic__create_device(struct kvm *kvm, enum irqchip_type type)
>> {
>> int err;
>> u64 cpu_if_addr = ARM_GIC_CPUI_BASE;
>> u64 dist_addr = ARM_GIC_DIST_BASE;
>> + u64 redist_addr = dist_addr - nr_redists * ARM_GIC_REDIST_SIZE;
>
> You are doing a similar offsetting further down. Consider having a macro
> that computes the redist base from the dist base.
>
>> struct kvm_create_device gic_device = {
>> .flags = 0,
>> };
>> @@ -28,11 +39,19 @@ static int gic__create_device(struct kvm *kvm, enum irqchip_type type)
>> .group = KVM_DEV_ARM_VGIC_GRP_ADDR,
>> .addr = (u64)(unsigned long)&dist_addr,
>> };
>> + struct kvm_device_attr redist_attr = {
>> + .group = KVM_DEV_ARM_VGIC_GRP_ADDR,
>> + .attr = KVM_VGIC_V3_ADDR_TYPE_REDIST,
>> + .addr = (u64)(unsigned long)&redist_addr,
>> + };
>>
>> switch (type) {
>> case IRQCHIP_GICV2:
>> gic_device.type = KVM_DEV_TYPE_ARM_VGIC_V2;
>> break;
>> + case IRQCHIP_GICV3:
>> + gic_device.type = KVM_DEV_TYPE_ARM_VGIC_V3;
>> + break;
>> default:
>> return -ENODEV;
>> }
>> @@ -48,6 +67,10 @@ static int gic__create_device(struct kvm *kvm, enum irqchip_type type)
>> dist_attr.attr = KVM_VGIC_V2_ADDR_TYPE_DIST;
>> err = ioctl(gic_fd, KVM_SET_DEVICE_ATTR, &cpu_if_attr);
>> break;
>> + case IRQCHIP_GICV3:
>> + dist_attr.attr = KVM_VGIC_V3_ADDR_TYPE_DIST;
>> + err = ioctl(gic_fd, KVM_SET_DEVICE_ATTR, &redist_attr);
>> + break;
>> default:
>> return -ENODEV;
>> }
>> @@ -55,6 +78,8 @@ static int gic__create_device(struct kvm *kvm, enum irqchip_type type)
>> return err;
>>
>> err = ioctl(gic_fd, KVM_SET_DEVICE_ATTR, &dist_attr);
>> + if (err)
>> + return err;
>
> Looks like a fairly useless statement...
Sorry, rebasing artefact, this gets amended in the next patch. I have
fixed it now in here.
>>
>> return err;
>> }
>> @@ -162,17 +187,25 @@ void gic__generate_fdt_nodes(void *fdt, u32 phandle, enum irqchip_type type)
>> u64 reg_prop[] = {
>> cpu_to_fdt64(ARM_GIC_DIST_BASE),
>> cpu_to_fdt64(ARM_GIC_DIST_SIZE),
>> - cpu_to_fdt64(ARM_GIC_CPUI_BASE),
>> - cpu_to_fdt64(ARM_GIC_CPUI_SIZE),
>> + 0, 0, /* to be filled */
>> };
>>
>> switch (type) {
>> case IRQCHIP_GICV2:
>> compatible = "arm,cortex-a15-gic";
>> + reg_prop[2] = ARM_GIC_CPUI_BASE;
>> + reg_prop[3] = ARM_GIC_CPUI_SIZE;
>> + break;
>> + case IRQCHIP_GICV3:
>> + compatible = "arm,gic-v3";
>> + reg_prop[2] = ARM_GIC_DIST_BASE - nr_redists * ARM_GIC_REDIST_SIZE;
>> + reg_prop[3] = ARM_GIC_REDIST_SIZE * nr_redists;
>> break;
>> default:
>> return;
>> }
>> + reg_prop[2] = cpu_to_fdt64(reg_prop[2]);
>> + reg_prop[3] = cpu_to_fdt64(reg_prop[3]);
>
> I'd find it more readable if you did the cpu_to_fdt64() as part of the
> initial assignment.
Agreed, that looks much nicer now that I use a separate variable for the
GIC redist base address (instead of nr_redist).
>>
>> _FDT(fdt_begin_node(fdt, "intc"));
>> _FDT(fdt_property_string(fdt, "compatible", compatible));
>> diff --git a/arm/include/arm-common/gic.h b/arm/include/arm-common/gic.h
>> index f5f6707..8d6ab01 100644
>> --- a/arm/include/arm-common/gic.h
>> +++ b/arm/include/arm-common/gic.h
>> @@ -21,7 +21,7 @@
>> #define GIC_MAX_CPUS 8
>> #define GIC_MAX_IRQ 255
>>
>> -enum irqchip_type {IRQCHIP_DEFAULT, IRQCHIP_GICV2};
>> +enum irqchip_type {IRQCHIP_DEFAULT, IRQCHIP_GICV2, IRQCHIP_GICV3};
>>
>> struct kvm;
>>
>> diff --git a/arm/include/arm-common/kvm-arch.h b/arm/include/arm-common/kvm-arch.h
>> index 082131d..be66a76 100644
>> --- a/arm/include/arm-common/kvm-arch.h
>> +++ b/arm/include/arm-common/kvm-arch.h
>> @@ -17,10 +17,8 @@
>>
>> #define ARM_GIC_DIST_BASE (ARM_AXI_AREA - ARM_GIC_DIST_SIZE)
>> #define ARM_GIC_CPUI_BASE (ARM_GIC_DIST_BASE - ARM_GIC_CPUI_SIZE)
>> -#define ARM_GIC_SIZE (ARM_GIC_DIST_SIZE + ARM_GIC_CPUI_SIZE)
>>
>> #define ARM_IOPORT_SIZE (ARM_MMIO_AREA - ARM_IOPORT_AREA)
>> -#define ARM_VIRTIO_MMIO_SIZE (ARM_AXI_AREA - (ARM_MMIO_AREA + ARM_GIC_SIZE))
>> #define ARM_PCI_CFG_SIZE (1ULL << 24)
>> #define ARM_PCI_MMIO_SIZE (ARM_MEMORY_AREA - \
>> (ARM_AXI_AREA + ARM_PCI_CFG_SIZE))
>> @@ -30,6 +28,13 @@
>> #define KVM_PCI_MMIO_AREA (KVM_PCI_CFG_AREA + ARM_PCI_CFG_SIZE)
>> #define KVM_VIRTIO_MMIO_AREA ARM_MMIO_AREA
>>
>> +/*
>> + * On a GICv3 there must be one redistributor per vCPU.
>> + * The value here is the size for one, we multiply this at runtime with
>> + * the number of requested vCPUs to get the actual size.
>> + */
>> +#define ARM_GIC_REDIST_SIZE 0x20000
>> +
>> #define KVM_IRQ_OFFSET GIC_SPI_IRQ_BASE
>>
>> #define KVM_VM_TYPE 0
>> @@ -45,9 +50,14 @@ static inline bool arm_addr_in_ioport_region(u64 phys_addr)
>> return phys_addr >= KVM_IOPORT_AREA && phys_addr < limit;
>> }
>>
>> -static inline bool arm_addr_in_virtio_mmio_region(u64 phys_addr)
>> +static inline bool arm_addr_in_virtio_mmio_region(int nr_redists, u64 phys_addr)
>> {
>> - u64 limit = KVM_VIRTIO_MMIO_AREA + ARM_VIRTIO_MMIO_SIZE;
>> + u64 limit = ARM_AXI_AREA - ARM_GIC_DIST_SIZE;
>> +
>> + if (nr_redists)
>> + limit -= ARM_GIC_REDIST_SIZE * nr_redists;
>> + else
>> + limit -= ARM_GIC_CPUI_SIZE;
>> return phys_addr >= KVM_VIRTIO_MMIO_AREA && phys_addr < limit;
>> }
>>
>> diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
>> index ab08815..a3344fa 100644
>> --- a/arm/kvm-cpu.c
>> +++ b/arm/kvm-cpu.c
>> @@ -142,7 +142,9 @@ bool kvm_cpu__handle_exit(struct kvm_cpu *vcpu)
>> bool kvm_cpu__emulate_mmio(struct kvm_cpu *vcpu, u64 phys_addr, u8 *data,
>> u32 len, u8 is_write)
>> {
>> - if (arm_addr_in_virtio_mmio_region(phys_addr)) {
>> + int nr_redists = 0;
>> +
>> + if (arm_addr_in_virtio_mmio_region(nr_redists, phys_addr)) {
>> return kvm__emulate_mmio(vcpu, phys_addr, data, len, is_write);
>> } else if (arm_addr_in_ioport_region(phys_addr)) {
>> int direction = is_write ? KVM_EXIT_IO_OUT : KVM_EXIT_IO_IN;
>>
>
> Ouch. This feels really ugly. Why don't you have the GIC code export a
> structure that contains the boundaries of the GIC (irrespective of its
> type), and use that to compute the limit? I don't think we want this
> nr_redists to propagate beyond the GIC code at all.
Looking more closely at the code I wonder why we differentiate beyond
the IO port region anyway. I rewrote this now without actually checking
for the GIC region at all. This simplified a lot and allows us to get
rid of nr_redists completely.
Cheers,
Andre.
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