Subject: [PATCH 05/13] KVM: arm64: handle ITS related GICv3 redistributor registers

From: [email-masked] (Eric Auger)
Date: Tue, 09 Jun 2015 10:52:19 +0200

On 05/29/2015 11:53 AM, Andre Przywara wrote:
> In the GICv3 redistributor there are the PENDBASER and PROPBASER
> registers which we did not emulate so far, as they only make sense
> when having an ITS. In preparation for that emulate those MMIO
> accesses by storing the 64-bit data written into it into a variable
> which we later read in the ITS emulation.
> 
> Signed-off-by: Andre Przywara <[email-masked]>
> ---
>  include/kvm/arm_vgic.h      |  4 ++++
>  virt/kvm/arm/vgic-v3-emul.c | 43 +++++++++++++++++++++++++++++++++++++++++++
>  virt/kvm/arm/vgic.c         | 35 +++++++++++++++++++++++++++++++++++
>  virt/kvm/arm/vgic.h         |  4 ++++
>  4 files changed, 86 insertions(+)
> 
> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
> index 37725bb..9ea0b3b 100644
> --- a/include/kvm/arm_vgic.h
> +++ b/include/kvm/arm_vgic.h
> @@ -256,6 +256,10 @@ struct vgic_dist {
>  	struct vgic_vm_ops	vm_ops;
>  	struct vgic_io_device	dist_iodev;
>  	struct vgic_io_device	*redist_iodevs;
> +
add some comments?
/* LPI config table shared by all distributors */
> +	u64			propbaser;
/* LPI pending table per distributors */
> +	u64			*pendbaser;
> +	bool			lpis_enabled;
>  };
>  
>  struct vgic_v2_cpu_if {
> diff --git a/virt/kvm/arm/vgic-v3-emul.c b/virt/kvm/arm/vgic-v3-emul.c
> index 16c6d8a..04f3aed 100644
> --- a/virt/kvm/arm/vgic-v3-emul.c
> +++ b/virt/kvm/arm/vgic-v3-emul.c
> @@ -607,6 +607,37 @@ static bool handle_mmio_cfg_reg_redist(struct kvm_vcpu *vcpu,
>  	return vgic_handle_cfg_reg(reg, mmio, offset);
>  }
>  
> +/* We don't trigger any actions here, just store the register value */
> +static bool handle_mmio_propbaser_redist(struct kvm_vcpu *vcpu,
> +					 struct kvm_exit_mmio *mmio,
> +					 phys_addr_t offset)
> +{
> +	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
> +	int mode = ACCESS_READ_VALUE;
> +
you may add the same comment as below?
> +	mode |= dist->lpis_enabled ? ACCESS_WRITE_IGNORED : ACCESS_WRITE_VALUE;
> +	vgic_handle_base_register(vcpu, mmio, offset, &dist->propbaser, mode);
having the PROPBASER programmed to different values on different redist
with EnableLPIs==1 also is unpredictable. Do we plan to check that
somewhere? Allow a single write?
> +
> +	return false;
> +}
> +
> +/* We don't trigger any actions here, just store the register value */
> +static bool handle_mmio_pendbaser_redist(struct kvm_vcpu *vcpu,
> +					 struct kvm_exit_mmio *mmio,
> +					 phys_addr_t offset)
> +{
> +	struct kvm_vcpu *rdvcpu = mmio->private;
> +	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
> +	int mode = ACCESS_READ_VALUE;
> +
> +	/* Storing a value with LPIs already enabled is undefined */
> +	mode |= dist->lpis_enabled ? ACCESS_WRITE_IGNORED : ACCESS_WRITE_VALUE;
> +	vgic_handle_base_register(vcpu, mmio, offset,
> +				  &dist->pendbaser[rdvcpu->vcpu_id], mode);
pendbaser is not yet allocated. Wouldn't it make sense to introduce that
patch later on?

Eric
> +
> +	return false;
> +}
> +
>  #define SGI_base(x) ((x) + SZ_64K)
>  
>  static const struct vgic_io_range vgic_redist_ranges[] = {
> @@ -635,6 +666,18 @@ static const struct vgic_io_range vgic_redist_ranges[] = {
>  		.handle_mmio    = handle_mmio_raz_wi,
>  	},
>  	{
> +		.base		= GICR_PENDBASER,
> +		.len		= 0x08,
> +		.bits_per_irq	= 0,
> +		.handle_mmio	= handle_mmio_pendbaser_redist,
> +	},
> +	{
> +		.base		= GICR_PROPBASER,
> +		.len		= 0x08,
> +		.bits_per_irq	= 0,
> +		.handle_mmio	= handle_mmio_propbaser_redist,
> +	},
> +	{
>  		.base           = GICR_IDREGS,
>  		.len            = 0x30,
>  		.bits_per_irq   = 0,
> diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
> index 2e9723aa..0a9236d 100644
> --- a/virt/kvm/arm/vgic.c
> +++ b/virt/kvm/arm/vgic.c
> @@ -448,6 +448,41 @@ void vgic_reg_access(struct kvm_exit_mmio *mmio, u32 *reg,
>  	}
>  }
>  
> +/* handle a 64-bit register access */
> +void vgic_handle_base_register(struct kvm_vcpu *vcpu,
> +			       struct kvm_exit_mmio *mmio,
> +			       phys_addr_t offset, u64 *basereg,
> +			       int mode)
> +{
> +	u32 reg;
> +	u64 breg;
> +
> +	switch (offset & ~3) {
> +	case 0x00:
> +		breg = *basereg;
> +		reg = lower_32_bits(breg);
> +		vgic_reg_access(mmio, &reg, offset & 3, mode);
> +		if (mmio->is_write && (mode & ACCESS_WRITE_VALUE)) {
> +			breg &= GENMASK_ULL(63, 32);
> +			breg |= reg;
> +			*basereg = breg;
> +		}
> +		break;
> +	case 0x04:
> +		breg = *basereg;
> +		reg = upper_32_bits(breg);
> +		vgic_reg_access(mmio, &reg, offset & 3, mode);
> +		if (mmio->is_write && (mode & ACCESS_WRITE_VALUE)) {
> +			breg  = lower_32_bits(breg);
> +			breg |= (u64)reg << 32;
> +			*basereg = breg;
> +		}
> +		break;
> +	}
> +}
> +
> +
> +
>  bool handle_mmio_raz_wi(struct kvm_vcpu *vcpu, struct kvm_exit_mmio *mmio,
>  			phys_addr_t offset)
>  {
> diff --git a/virt/kvm/arm/vgic.h b/virt/kvm/arm/vgic.h
> index a093f5c..b2d791c 100644
> --- a/virt/kvm/arm/vgic.h
> +++ b/virt/kvm/arm/vgic.h
> @@ -71,6 +71,10 @@ void vgic_reg_access(struct kvm_exit_mmio *mmio, u32 *reg,
>  		     phys_addr_t offset, int mode);
>  bool handle_mmio_raz_wi(struct kvm_vcpu *vcpu, struct kvm_exit_mmio *mmio,
>  			phys_addr_t offset);
> +void vgic_handle_base_register(struct kvm_vcpu *vcpu,
> +			       struct kvm_exit_mmio *mmio,
> +			       phys_addr_t offset, u64 *basereg,
> +			       int mode);
>  
>  static inline
>  u32 mmio_data_read(struct kvm_exit_mmio *mmio, u32 mask)
>