Re: [PATCH v4 33/56] KVM: arm/arm64: vgic-new: Add GICv3 MMIO handling framework

[Christoffer Dall <christoffer.dall@linaro.org>]

On Mon, May 16, 2016 at 10:53:21AM +0100, Andre Przywara wrote:
> Create a new file called vgic-mmio-v3.c and describe the GICv3
> distributor and redistributor registers there.
> This adds a special macro to deal with the split of SGI/PPI in the
> redistributor and SPIs in the distributor, which allows us to reuse
> the existing GICv2 handlers for those registers which are compatible.
> Also we provide a function to deal with the registration of the two
> separate redistributor frames per VCPU.
> 
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> Reviewed-by: Eric Auger <eric.auger@linaro.org>
> ---
> Changelog RFC..v1:
> - adapt to new MMIO registration approach:
>   register one device for the distributor and two for each VCPU
> - implement special handling for private interrupts
> - remove empty stub functions
> - make IGROUPR return RAO
> 
> Changelog v1 .. v2:
> - adapt to new framework, introduce vgic-mmio-v3.c
> - remove userland register access functions (for now)
> - precompute .len when describing a VGIC register
> - add missed pointer incrementation on registering redist regions
> - replace _nyi stub functions with raz/wi versions
> 
> Changelog v2 .. v3:
> - replace inclusion of kvm/vgic/vgic.h with kvm/arm_vgic.h
> - add prototype and stub code for vgic_register_redist_iodevs
> - rename register struct variables _rdbase_ and _sgibase_
> 
> Changelog v3 .. v4:
> - specify accessor width
> 
>  virt/kvm/arm/vgic/vgic-mmio-v3.c | 224 +++++++++++++++++++++++++++++++++++++++
>  virt/kvm/arm/vgic/vgic-mmio.c    |   5 +
>  virt/kvm/arm/vgic/vgic-mmio.h    |   2 +
>  virt/kvm/arm/vgic/vgic.h         |   7 ++
>  4 files changed, 238 insertions(+)
>  create mode 100644 virt/kvm/arm/vgic/vgic-mmio-v3.c
> 
> diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> new file mode 100644
> index 0000000..31f1a13
> --- /dev/null
> +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> @@ -0,0 +1,224 @@
> +/*
> + * VGICv3 MMIO handling functions
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/irqchip/arm-gic-v3.h>
> +#include <linux/kvm.h>
> +#include <linux/kvm_host.h>
> +#include <kvm/iodev.h>
> +#include <kvm/arm_vgic.h>
> +
> +#include <asm/kvm_emulate.h>
> +
> +#include "vgic.h"
> +#include "vgic-mmio.h"
> +
> +/*
> + * The GICv3 per-IRQ registers are split to control PPIs and SGIs in the
> + * redistributors, while SPIs are covered by registers in the distributor
> + * block. Trying to set private IRQs in this block gets ignored.
> + * We take some special care here to fix the calculation of the register
> + * offset.
> + */
> +#define REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(off, rd, wr, bpi, acc)	\
> +	{								\
> +		.reg_offset = off,					\
> +		.bits_per_irq = bpi,					\
> +		.len = (bpi * VGIC_NR_PRIVATE_IRQS) / 8,		\
> +		.access_flags = acc,					\
> +		.read = vgic_mmio_read_raz,				\
> +		.write = vgic_mmio_write_wi,				\
> +	}, {								\
> +		.reg_offset = off + (bpi * VGIC_NR_PRIVATE_IRQS) / 8,	\
> +		.bits_per_irq = bpi,					\
> +		.len = (bpi * (1024 - VGIC_NR_PRIVATE_IRQS)) / 8,	\
> +		.access_flags = acc,					\
> +		.read = rd,						\
> +		.write = wr,						\
> +	}
> +
> +static const struct vgic_register_region vgic_v3_dist_registers[] = {
> +	REGISTER_DESC_WITH_LENGTH(GICD_CTLR,
> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 16,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_IGROUPR,
> +		vgic_mmio_read_rao, vgic_mmio_write_wi, 1,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ISENABLER,
> +		vgic_mmio_read_enable, vgic_mmio_write_senable, 1,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ICENABLER,
> +		vgic_mmio_read_enable, vgic_mmio_write_cenable, 1,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ISPENDR,
> +		vgic_mmio_read_pending, vgic_mmio_write_spending, 1,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ICPENDR,
> +		vgic_mmio_read_pending, vgic_mmio_write_cpending, 1,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ISACTIVER,
> +		vgic_mmio_read_active, vgic_mmio_write_sactive, 1,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ICACTIVER,
> +		vgic_mmio_read_active, vgic_mmio_write_cactive, 1,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_IPRIORITYR,
> +		vgic_mmio_read_priority, vgic_mmio_write_priority, 8,
> +		VGIC_ACCESS_32bit | VGIC_ACCESS_8bit),
> +	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ITARGETSR,
> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 8,
> +		VGIC_ACCESS_32bit | VGIC_ACCESS_8bit),
> +	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ICFGR,
> +		vgic_mmio_read_config, vgic_mmio_write_config, 2,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_IGRPMODR,
> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 1,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_IROUTER,
> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 64,
> +		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_LENGTH(GICD_IDREGS,
> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 48,
> +		VGIC_ACCESS_32bit),
> +};
> +
> +static const struct vgic_register_region vgic_v3_rdbase_registers[] = {
> +	REGISTER_DESC_WITH_LENGTH(GICR_CTLR,
> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 4,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_LENGTH(GICR_IIDR,
> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 4,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_LENGTH(GICR_TYPER,
> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 8,
> +		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_LENGTH(GICR_PROPBASER,
> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 8,
> +		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_LENGTH(GICR_PENDBASER,
> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 8,
> +		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_LENGTH(GICR_IDREGS,
> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 48,
> +		VGIC_ACCESS_32bit),
> +};
> +
> +static const struct vgic_register_region vgic_v3_sgibase_registers[] = {
> +	REGISTER_DESC_WITH_LENGTH(GICR_IGROUPR0,
> +		vgic_mmio_read_rao, vgic_mmio_write_wi, 4,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_LENGTH(GICR_ISENABLER0,
> +		vgic_mmio_read_enable, vgic_mmio_write_senable, 4,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_LENGTH(GICR_ICENABLER0,
> +		vgic_mmio_read_enable, vgic_mmio_write_cenable, 4,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_LENGTH(GICR_ISPENDR0,
> +		vgic_mmio_read_pending, vgic_mmio_write_spending, 4,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_LENGTH(GICR_ICPENDR0,
> +		vgic_mmio_read_pending, vgic_mmio_write_cpending, 4,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_LENGTH(GICR_ISACTIVER0,
> +		vgic_mmio_read_active, vgic_mmio_write_sactive, 4,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_LENGTH(GICR_ICACTIVER0,
> +		vgic_mmio_read_active, vgic_mmio_write_cactive, 4,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_LENGTH(GICR_IPRIORITYR0,
> +		vgic_mmio_read_priority, vgic_mmio_write_priority, 32,
> +		VGIC_ACCESS_32bit | VGIC_ACCESS_8bit),
> +	REGISTER_DESC_WITH_LENGTH(GICR_ICFGR0,
> +		vgic_mmio_read_config, vgic_mmio_write_config, 8,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_LENGTH(GICR_IGRPMODR0,
> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 4,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_LENGTH(GICR_NSACR,
> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 4,
> +		VGIC_ACCESS_32bit),
> +};
> +
> +unsigned int vgic_v3_init_dist_iodev(struct vgic_io_device *dev)
> +{
> +	dev->regions = vgic_v3_dist_registers;
> +	dev->nr_regions = ARRAY_SIZE(vgic_v3_dist_registers);
> +
> +	kvm_iodevice_init(&dev->dev, &kvm_io_gic_ops);
> +
> +	return SZ_64K;
> +}
> +
> +int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t redist_base_address)
> +{
> +	int nr_vcpus = atomic_read(&kvm->online_vcpus);
> +	struct kvm_vcpu *vcpu;
> +	struct vgic_io_device *devices;
> +	int c, ret = 0;
> +
> +	devices = kmalloc(sizeof(struct vgic_io_device) * nr_vcpus * 2,
> +			  GFP_KERNEL);
> +	if (!devices)
> +		return -ENOMEM;
> +
> +	kvm_for_each_vcpu(c, vcpu, kvm) {
> +		gpa_t rd_base = redist_base_address + c * SZ_64K * 2;
> +		gpa_t sgi_base = rd_base + SZ_64K;
> +		struct vgic_io_device *rd_dev = &devices[c * 2];
> +		struct vgic_io_device *sgi_dev = &devices[c * 2 + 1];
> +
> +		kvm_iodevice_init(&rd_dev->dev, &kvm_io_gic_ops);
> +		rd_dev->base_addr = rd_base;
> +		rd_dev->regions = vgic_v3_rdbase_registers;
> +		rd_dev->nr_regions = ARRAY_SIZE(vgic_v3_rdbase_registers);
> +		rd_dev->redist_vcpu = vcpu;
> +
> +		mutex_lock(&kvm->slots_lock);
> +		ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, rd_base,
> +					      SZ_64K, &rd_dev->dev);
> +		mutex_unlock(&kvm->slots_lock);
> +
> +		if (ret)
> +			break;
> +
> +		kvm_iodevice_init(&sgi_dev->dev, &kvm_io_gic_ops);
> +		sgi_dev->base_addr = sgi_base;
> +		sgi_dev->regions = vgic_v3_sgibase_registers;
> +		sgi_dev->nr_regions = ARRAY_SIZE(vgic_v3_sgibase_registers);
> +		sgi_dev->redist_vcpu = vcpu;
> +
> +		mutex_lock(&kvm->slots_lock);
> +		ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, sgi_base,
> +					      SZ_64K, &sgi_dev->dev);
> +		mutex_unlock(&kvm->slots_lock);
> +		if (ret) {
> +			kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS,
> +						  &devices[c * 2].dev);

nit: you could replace this last bit by &rd_dev->dev

but it's up to you what you prefer.

Otherwise:

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>