Re: [PATCH v4 05/12] KVM: arm64: introduce ITS emulation file with stub functions

[Eric Auger <eric.auger@linaro.org>]

Hi Marc,
On 04/07/2016 04:04 PM, Marc Zyngier wrote:
> On 26/03/16 02:14, 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.
>> Introduce the skeleton with function stubs to be filled later.
>> 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>
>> ---
>>  arch/arm64/kvm/Makefile            |  1 +
>>  include/kvm/vgic/vgic.h            |  6 +++
>>  include/linux/irqchip/arm-gic-v3.h |  1 +
>>  virt/kvm/arm/vgic/its-emul.c       | 84 ++++++++++++++++++++++++++++++++++++++
>>  virt/kvm/arm/vgic/vgic.h           | 14 +++++++
>>  virt/kvm/arm/vgic/vgic_init.c      |  6 +++
>>  virt/kvm/arm/vgic/vgic_mmio.c      | 18 ++++++--
>>  7 files changed, 126 insertions(+), 4 deletions(-)
>>  create mode 100644 virt/kvm/arm/vgic/its-emul.c
>>
>> diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
>> index 2f5d431..3bec10e 100644
>> --- a/arch/arm64/kvm/Makefile
>> +++ b/arch/arm64/kvm/Makefile
>> @@ -28,6 +28,7 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-v2.o
>>  kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-v3.o
>>  kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic_mmio.o
>>  kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic_kvm_device.o
>> +kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/its-emul.o
>>  else
>>  kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic.o
>>  kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic-v2.o
>> diff --git a/include/kvm/vgic/vgic.h b/include/kvm/vgic/vgic.h
>> index 8ea5dd7..c79bed5 100644
>> --- a/include/kvm/vgic/vgic.h
>> +++ b/include/kvm/vgic/vgic.h
>> @@ -112,6 +112,11 @@ struct vgic_io_device {
>>  	struct kvm_io_device dev;
>>  };
>>  
>> +struct vgic_its {
>> +	bool			enabled;
>> +	spinlock_t		lock;
>> +};
>> +
>>  struct vgic_dist {
>>  	bool			in_kernel;
>>  	bool			ready;
>> @@ -153,6 +158,7 @@ struct vgic_dist {
>>  	u64			*pendbaser;
>>  
>>  	bool			lpis_enabled;
>> +	struct vgic_its		its;
>>  };
>>  
>>  struct vgic_v2_cpu_if {
>> diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
>> index d5d798b..a813c3e 100644
>> --- a/include/linux/irqchip/arm-gic-v3.h
>> +++ b/include/linux/irqchip/arm-gic-v3.h
>> @@ -177,6 +177,7 @@
>>  #define GITS_CWRITER			0x0088
>>  #define GITS_CREADR			0x0090
>>  #define GITS_BASER			0x0100
>> +#define GITS_IDREGS_BASE		0xffd0
>>  #define GITS_PIDR2			GICR_PIDR2
>>  
>>  #define GITS_TRANSLATER			0x10040
>> diff --git a/virt/kvm/arm/vgic/its-emul.c b/virt/kvm/arm/vgic/its-emul.c
>> new file mode 100644
>> index 0000000..49dd5e4
>> --- /dev/null
>> +++ b/virt/kvm/arm/vgic/its-emul.c
>> @@ -0,0 +1,84 @@
>> +/*
>> + * GICv3 ITS emulation
>> + *
>> + * Copyright (C) 2015 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"
>> +
>> +struct vgic_register_region its_registers[] = {
>> +	REGISTER_DESC_WITH_LENGTH(GITS_CTLR,
>> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 4),
>> +	REGISTER_DESC_WITH_LENGTH(GITS_IIDR,
>> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 4),
>> +	REGISTER_DESC_WITH_LENGTH(GITS_TYPER,
>> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 4),
> 
> GITS_TYPER is a 64bit register with plenty of things in the upper bits.
In practice I think the 32 upper bits are reserved.

Eric
> 
>> +	REGISTER_DESC_WITH_LENGTH(GITS_CBASER,
>> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 8),
>> +	REGISTER_DESC_WITH_LENGTH(GITS_CWRITER,
>> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 8),
>> +	REGISTER_DESC_WITH_LENGTH(GITS_CREADR,
>> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 8),
>> +	REGISTER_DESC_WITH_LENGTH(GITS_BASER,
>> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 0x40),
>> +	REGISTER_DESC_WITH_LENGTH(GITS_IDREGS_BASE,
>> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 0x30),
>> +};
>> +
>> +/* This is called on setting the LPI enable bit in the redistributor. */
>> +void vgic_enable_lpis(struct kvm_vcpu *vcpu)
>> +{
>> +}
>> +
>> +int vits_init(struct kvm *kvm)
>> +{
>> +	struct vgic_dist *dist = &kvm->arch.vgic;
>> +	struct vgic_its *its = &dist->its;
>> +	struct vgic_io_device *regions;
>> +	int ret, i;
>> +
>> +	spin_lock_init(&its->lock);
>> +
>> +	regions = kmalloc_array(ARRAY_SIZE(its_registers),
>> +				sizeof(struct vgic_io_device), GFP_KERNEL);
>> +
>> +	for (i = 0; i < ARRAY_SIZE(its_registers); i++) {
>> +		regions[i].base_addr = dist->vgic_its_base;
>> +
>> +		ret = kvm_vgic_register_mmio_region(kvm, NULL,
>> +						    &its_registers[i],
>> +						    &regions[i], 0, false);
>> +	}
>> +
>> +	if (ret)
>> +		return ret;
>> +
>> +	its->enabled = false;
>> +
>> +	return -ENXIO;
>> +}
>> diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
>> index db9dfd7..4e7dcb8 100644
>> --- a/virt/kvm/arm/vgic/vgic.h
>> +++ b/virt/kvm/arm/vgic/vgic.h
>> @@ -60,6 +60,9 @@ void vgic_v3_enable(struct kvm_vcpu *vcpu);
>>  int vgic_v3_probe(struct device_node *vgic_node);
>>  int vgic_v3_map_resources(struct kvm *kvm);
>>  int vgic_register_redist_regions(struct kvm *kvm, gpa_t dist_base_address);
>> +
>> +int vits_init(struct kvm *kvm);
>> +void vgic_enable_lpis(struct kvm_vcpu *vcpu);
>>  #else
>>  static inline void vgic_v3_irq_change_affinity(struct kvm *kvm, u32 intid,
>>  					       u64 mpidr)
>> @@ -124,6 +127,16 @@ static inline int vgic_register_redist_regions(struct kvm *kvm,
>>  {
>>  	return -ENODEV;
>>  }
>> +
>> +int vits_init(struct kvm *kvm)
>> +{
>> +	return 0;
>> +}
>> +
>> +static inline void vgic_enable_lpis(struct kvm_vcpu *vcpu)
>> +{
>> +	return;
>> +}
>>  #endif
>>  
>>  void vgic_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
>> @@ -131,6 +144,7 @@ void vgic_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
>>  
>>  int vgic_lazy_init(struct kvm *kvm);
>>  int vgic_init(struct kvm *kvm);
>> +int vits_init(struct kvm *kvm);
>>  void kvm_register_vgic_device(unsigned long type);
>>  
>>  #endif
>> diff --git a/virt/kvm/arm/vgic/vgic_init.c b/virt/kvm/arm/vgic/vgic_init.c
>> index 2301e03..dcfb93d 100644
>> --- a/virt/kvm/arm/vgic/vgic_init.c
>> +++ b/virt/kvm/arm/vgic/vgic_init.c
>> @@ -252,6 +252,12 @@ int vgic_init(struct kvm *kvm)
>>  	if (ret)
>>  		goto out;
>>  
>> +	if (vgic_has_its(kvm)) {
>> +		ret = vits_init(kvm);
>> +		if (ret)
>> +			goto out;
>> +	}
> 
> You can move the vgic_has_its() test inside vits_init().
> 
>> +
>>  	kvm_for_each_vcpu(i, vcpu, kvm)
>>  		kvm_vgic_vcpu_init(vcpu);
>>  
>> diff --git a/virt/kvm/arm/vgic/vgic_mmio.c b/virt/kvm/arm/vgic/vgic_mmio.c
>> index 252b9aff..086555e 100644
>> --- a/virt/kvm/arm/vgic/vgic_mmio.c
>> +++ b/virt/kvm/arm/vgic/vgic_mmio.c
>> @@ -726,16 +726,26 @@ static int vgic_mmio_read_v3r_misc(struct kvm_vcpu *vcpu,
>>  				   struct kvm_io_device *this,
>>  				   gpa_t addr, int len, void *val)
>>  {
>> -	/* TODO: implement for ITS support */
>> -	return vgic_mmio_read_raz(vcpu, this, addr, len, val);
>> +	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
>> +	u32 reg = dist->lpis_enabled ? GICR_CTLR_ENABLE_LPIS : 0;
>> +
>> +	write_mask32(reg, addr & 3, len, val);
>> +	return 0;
>>  }
>>  
>>  static int vgic_mmio_write_v3r_misc(struct kvm_vcpu *vcpu,
>>  				    struct kvm_io_device *this,
>>  				    gpa_t addr, int len, const void *val)
>>  {
>> -	/* TODO: implement for ITS support */
>> -	return vgic_mmio_write_wi(vcpu, this, addr, len, val);
>> +	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
>> +	u32 reg = mask32(!!dist->lpis_enabled, addr & 3, len, val);
>> +
>> +	if (vgic_has_its(vcpu->kvm) && !dist->lpis_enabled &&
>> +	    (reg & GICR_CTLR_ENABLE_LPIS)) {
>> +		/* Eventually do something */
>> +	}
>> +
>> +	return 0;
>>  }
>>  
>>  static int vgic_mmio_read_v3r_iidr(struct kvm_vcpu *vcpu,
>>
> 
>