[PATCH v10 09/17] KVM: arm64: introduce ITS emulation file with MMIO framework

[eric.auger@redhat.com (Auger Eric)]

Hi Andre, Marc,

On 15/07/2016 13:43, Andre Przywara wrote:
> The ARM GICv3 ITS emulation code goes into a separate file, but needs
> to be connected to the GICv3 emulation, of which it is an option.
> The ITS MMIO handlers require the respective ITS pointer to be passed in,
> so we amend the existing VGIC MMIO framework to let it cope with that.
> Also we introduce the basic ITS data structure and initialize it, but
> don't return any success yet, as we are not yet ready for the show.
> 
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
>  include/kvm/arm_vgic.h           |  22 ++++++++-
>  virt/kvm/arm/vgic/vgic-its.c     | 103 +++++++++++++++++++++++++++++++++++++++
>  virt/kvm/arm/vgic/vgic-mmio-v3.c |  40 ++++++++++++++-
>  virt/kvm/arm/vgic/vgic-mmio.c    |  37 +++++++++++---
>  virt/kvm/arm/vgic/vgic-mmio.h    |  17 +++++--
>  virt/kvm/arm/vgic/vgic.h         |   7 +++
>  6 files changed, 213 insertions(+), 13 deletions(-)
>  create mode 100644 virt/kvm/arm/vgic/vgic-its.c
> 
> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
> index df2dec5..685f339 100644
> --- a/include/kvm/arm_vgic.h
> +++ b/include/kvm/arm_vgic.h
> @@ -108,15 +108,35 @@ struct vgic_irq {
>  };
>  
>  struct vgic_register_region;
> +struct vgic_its;
> +
> +enum iodev_type {
> +	IODEV_CPUIF,
> +	IODEV_DIST,
> +	IODEV_REDIST,
> +	IODEV_ITS
> +};
>  
>  struct vgic_io_device {
>  	gpa_t base_addr;
> -	struct kvm_vcpu *redist_vcpu;
> +	union {
> +		struct kvm_vcpu *redist_vcpu;
> +		struct vgic_its *its;
> +	};
>  	const struct vgic_register_region *regions;
> +	enum iodev_type iodev_type;
>  	int nr_regions;
>  	struct kvm_io_device dev;
>  };
>  
> +struct vgic_its {
> +	/* The base address of the ITS control register frame */
> +	gpa_t			vgic_its_base;
> +
> +	bool			enabled;
> +	struct vgic_io_device	iodev;
> +};
> +
>  struct vgic_dist {
>  	bool			in_kernel;
>  	bool			ready;
> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
> new file mode 100644
> index 0000000..4654d6e
> --- /dev/null
> +++ b/virt/kvm/arm/vgic/vgic-its.c
> @@ -0,0 +1,103 @@
> +/*
> + * GICv3 ITS emulation
> + *
> + * Copyright (C) 2015,2016 ARM Ltd.
> + * Author: Andre Przywara <andre.przywara@arm.com>
> + *
> + * 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.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/cpu.h>
> +#include <linux/kvm.h>
> +#include <linux/kvm_host.h>
> +#include <linux/interrupt.h>
> +
> +#include <linux/irqchip/arm-gic-v3.h>
> +
> +#include <asm/kvm_emulate.h>
> +#include <asm/kvm_arm.h>
> +#include <asm/kvm_mmu.h>
> +
> +#include "vgic.h"
> +#include "vgic-mmio.h"
> +
> +#define REGISTER_ITS_DESC(off, rd, wr, length, acc)		\
> +{								\
> +	.reg_offset = off,					\
> +	.len = length,						\
> +	.access_flags = acc,					\
> +	.its_read = rd,						\
> +	.its_write = wr,					\
> +}
> +
> +static unsigned long its_mmio_read_raz(struct kvm *kvm, struct vgic_its *its,
> +				       gpa_t addr, unsigned int len)
> +{
> +	return 0;
> +}
> +
> +static void its_mmio_write_wi(struct kvm *kvm, struct vgic_its *its,
> +			      gpa_t addr, unsigned int len, unsigned long val)
> +{
> +	/* Ignore */
> +}
> +
> +static struct vgic_register_region its_registers[] = {
> +	REGISTER_ITS_DESC(GITS_CTLR,
> +		its_mmio_read_raz, its_mmio_write_wi, 4,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_ITS_DESC(GITS_IIDR,
> +		its_mmio_read_raz, its_mmio_write_wi, 4,
> +		VGIC_ACCESS_32bit),
> +	REGISTER_ITS_DESC(GITS_TYPER,
> +		its_mmio_read_raz, its_mmio_write_wi, 8,
> +		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
> +	REGISTER_ITS_DESC(GITS_CBASER,
> +		its_mmio_read_raz, its_mmio_write_wi, 8,
> +		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
> +	REGISTER_ITS_DESC(GITS_CWRITER,
> +		its_mmio_read_raz, its_mmio_write_wi, 8,
> +		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
> +	REGISTER_ITS_DESC(GITS_CREADR,
> +		its_mmio_read_raz, its_mmio_write_wi, 8,
> +		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
> +	REGISTER_ITS_DESC(GITS_BASER,
> +		its_mmio_read_raz, its_mmio_write_wi, 0x40,
> +		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
> +	REGISTER_ITS_DESC(GITS_IDREGS_BASE,
> +		its_mmio_read_raz, its_mmio_write_wi, 0x30,
> +		VGIC_ACCESS_32bit),
> +};
> +
> +static int vgic_its_init_its(struct kvm *kvm, struct vgic_its *its)
> +{
> +	struct vgic_io_device *iodev = &its->iodev;
> +	int ret;
> +
> +	if (IS_VGIC_ADDR_UNDEF(its->vgic_its_base))
> +		return -ENXIO;
> +
> +	iodev->regions = its_registers;
> +	iodev->nr_regions = ARRAY_SIZE(its_registers);
> +	kvm_iodevice_init(&iodev->dev, &kvm_io_gic_ops);
> +
> +	iodev->base_addr = its->vgic_its_base;
> +	iodev->iodev_type = IODEV_ITS;
> +	iodev->its = its;
> +	mutex_lock(&kvm->slots_lock);
> +	ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, iodev->base_addr,
> +				      KVM_VGIC_V3_ITS_SIZE, &iodev->dev);
> +	mutex_unlock(&kvm->slots_lock);
> +
> +	return ret;
> +}
> diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> index 278bfbb..b92b7d6 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> @@ -42,6 +42,16 @@ static u64 update_64bit_reg(u64 reg, unsigned int offset, unsigned int len,
>  	return reg | ((u64)val << lower);
>  }
>  
> +bool vgic_has_its(struct kvm *kvm)
> +{
> +	struct vgic_dist *dist = &kvm->arch.vgic;
> +
> +	if (dist->vgic_model != KVM_DEV_TYPE_ARM_VGIC_V3)
> +		return false;
> +
> +	return false;
> +}
> +
>  static unsigned long vgic_mmio_read_v3_misc(struct kvm_vcpu *vcpu,
>  					    gpa_t addr, unsigned int len)
>  {
> @@ -132,6 +142,32 @@ static void vgic_mmio_write_irouter(struct kvm_vcpu *vcpu,
>  	vgic_put_irq(vcpu->kvm, irq);
>  }
>  
> +static unsigned long vgic_mmio_read_v3r_ctlr(struct kvm_vcpu *vcpu,
> +					     gpa_t addr, unsigned int len)
> +{
> +	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
> +
> +	return vgic_cpu->lpis_enabled ? GICR_CTLR_ENABLE_LPIS : 0;
> +}
> +
> +
> +static void vgic_mmio_write_v3r_ctlr(struct kvm_vcpu *vcpu,
> +				     gpa_t addr, unsigned int len,
> +				     unsigned long val)
> +{
> +	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
> +	bool was_enabled = vgic_cpu->lpis_enabled;
> +
> +	if (!vgic_has_its(vcpu->kvm))
> +		return;
> +
> +	vgic_cpu->lpis_enabled = val & GICR_CTLR_ENABLE_LPIS;
> +
> +	if (!was_enabled && vgic_cpu->lpis_enabled) {
> +		/* Eventually do something */
> +	}
> +}
> +
>  static unsigned long vgic_mmio_read_v3r_typer(struct kvm_vcpu *vcpu,
>  					      gpa_t addr, unsigned int len)
>  {
> @@ -372,7 +408,7 @@ static const struct vgic_register_region vgic_v3_dist_registers[] = {
>  
>  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_mmio_read_v3r_ctlr, vgic_mmio_write_v3r_ctlr, 4,
>  		VGIC_ACCESS_32bit),
>  	REGISTER_DESC_WITH_LENGTH(GICR_IIDR,
>  		vgic_mmio_read_v3r_iidr, vgic_mmio_write_wi, 4,
> @@ -450,6 +486,7 @@ int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t redist_base_address)
>  
>  		kvm_iodevice_init(&rd_dev->dev, &kvm_io_gic_ops);
>  		rd_dev->base_addr = rd_base;
> +		rd_dev->iodev_type = IODEV_REDIST;
>  		rd_dev->regions = vgic_v3_rdbase_registers;
>  		rd_dev->nr_regions = ARRAY_SIZE(vgic_v3_rdbase_registers);
>  		rd_dev->redist_vcpu = vcpu;
> @@ -464,6 +501,7 @@ int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t redist_base_address)
>  
>  		kvm_iodevice_init(&sgi_dev->dev, &kvm_io_gic_ops);
>  		sgi_dev->base_addr = sgi_base;
> +		sgi_dev->iodev_type = IODEV_REDIST;
>  		sgi_dev->regions = vgic_v3_sgibase_registers;
>  		sgi_dev->nr_regions = ARRAY_SIZE(vgic_v3_sgibase_registers);
>  		sgi_dev->redist_vcpu = vcpu;
> diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
> index 5e79e01..26be827 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio.c
> @@ -473,8 +473,7 @@ static int dispatch_mmio_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
>  {
>  	struct vgic_io_device *iodev = kvm_to_vgic_iodev(dev);
>  	const struct vgic_register_region *region;
> -	struct kvm_vcpu *r_vcpu;
> -	unsigned long data;
> +	unsigned long data = 0;
>  
>  	region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions,
>  				       addr - iodev->base_addr);
> @@ -483,8 +482,20 @@ static int dispatch_mmio_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
>  		return 0;
>  	}
>  
> -	r_vcpu = iodev->redist_vcpu ? iodev->redist_vcpu : vcpu;
> -	data = region->read(r_vcpu, addr, len);
> +	switch (iodev->iodev_type) {
> +	case IODEV_CPUIF:
> +		return 1;
This change causes a regression on AMD Seattle with QEMU (abort with
message "restoring 288 IRQs, but kernel supports max 32").
Shoudn't we have
		data = region->read(vcpu, addr, len);
		break;
This path is exercised by vgic_v2_cpuif_uaccess/vgic_uaccess
> +	case IODEV_DIST:
> +		data = region->read(vcpu, addr, len);
> +		break;
> +	case IODEV_REDIST:
> +		data = region->read(iodev->redist_vcpu, addr, len);
> +		break;
> +	case IODEV_ITS:
> +		data = region->its_read(vcpu->kvm, iodev->its, addr, len);
> +		break;
> +	}
> +
>  	vgic_data_host_to_mmio_bus(val, len, data);
>  	return 0;
>  }
> @@ -494,7 +505,6 @@ static int dispatch_mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
>  {
>  	struct vgic_io_device *iodev = kvm_to_vgic_iodev(dev);
>  	const struct vgic_register_region *region;
> -	struct kvm_vcpu *r_vcpu;
>  	unsigned long data = vgic_data_mmio_bus_to_host(val, len);
>  
>  	region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions,
> @@ -505,8 +515,20 @@ static int dispatch_mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
>  	if (!check_region(region, addr, len))
>  		return 0;
>  
> -	r_vcpu = iodev->redist_vcpu ? iodev->redist_vcpu : vcpu;
> -	region->write(r_vcpu, addr, len, data);
> +	switch (iodev->iodev_type) {
> +	case IODEV_CPUIF:
> +		break;
same here
region->write(vcpu, addr, len, data);

The above modifications fix the issue.

Eric
> +	case IODEV_DIST:
> +		region->write(vcpu, addr, len, data);
> +		break;
> +	case IODEV_REDIST:
> +		region->write(iodev->redist_vcpu, addr, len, data);
> +		break;
> +	case IODEV_ITS:
> +		region->its_write(vcpu->kvm, iodev->its, addr, len, data);
> +		break;
> +	}
> +
>  	return 0;
>  }
>  
> @@ -536,6 +558,7 @@ int vgic_register_dist_iodev(struct kvm *kvm, gpa_t dist_base_address,
>  	}
>  
>  	io_device->base_addr = dist_base_address;
> +	io_device->iodev_type = IODEV_DIST;
>  	io_device->redist_vcpu = NULL;
>  
>  	mutex_lock(&kvm->slots_lock);
> diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h
> index 71aa39d..366d663 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio.h
> +++ b/virt/kvm/arm/vgic/vgic-mmio.h
> @@ -21,10 +21,19 @@ struct vgic_register_region {
>  	unsigned int len;
>  	unsigned int bits_per_irq;
>  	unsigned int access_flags;
> -	unsigned long (*read)(struct kvm_vcpu *vcpu, gpa_t addr,
> -			      unsigned int len);
> -	void (*write)(struct kvm_vcpu *vcpu, gpa_t addr, unsigned int len,
> -		      unsigned long val);
> +	union {
> +		unsigned long (*read)(struct kvm_vcpu *vcpu, gpa_t addr,
> +				      unsigned int len);
> +		unsigned long (*its_read)(struct kvm *kvm, struct vgic_its *its,
> +					  gpa_t addr, unsigned int len);
> +	};
> +	union {
> +		void (*write)(struct kvm_vcpu *vcpu, gpa_t addr,
> +			      unsigned int len, unsigned long val);
> +		void (*its_write)(struct kvm *kvm, struct vgic_its *its,
> +				  gpa_t addr, unsigned int len,
> +				  unsigned long val);
> +	};
>  };
>  
>  extern struct kvm_io_device_ops kvm_io_gic_ops;
> diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
> index 5b79c34..31807c1 100644
> --- a/virt/kvm/arm/vgic/vgic.h
> +++ b/virt/kvm/arm/vgic/vgic.h
> @@ -72,6 +72,7 @@ void vgic_v3_enable(struct kvm_vcpu *vcpu);
>  int vgic_v3_probe(const struct gic_kvm_info *info);
>  int vgic_v3_map_resources(struct kvm *kvm);
>  int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t dist_base_address);
> +bool vgic_has_its(struct kvm *kvm);
>  #else
>  static inline void vgic_v3_process_maintenance(struct kvm_vcpu *vcpu)
>  {
> @@ -123,6 +124,12 @@ static inline int vgic_register_redist_iodevs(struct kvm *kvm,
>  {
>  	return -ENODEV;
>  }
> +
> +static inline bool vgic_has_its(struct kvm *kvm)
> +{
> +	return false;
> +}
> +
>  #endif
>  
>  int kvm_register_vgic_device(unsigned long type);
>