Subject: [PATCH 8/8] KVM: arm-vgic: Support CPU interface reg access

From: [email-masked] (Christoffer Dall)
Date: Wed, 25 Sep 2013 14:30:41 -0700

On Sun, Aug 25, 2013 at 04:24:20PM +0100, Alexander Graf wrote:
> 
> On 23.08.2013, at 20:20, Christoffer Dall wrote:
> 
> > Implement support for the CPU interface register access driven by MMIO
> > address offsets from the CPU interface base address.  Useful for user
> > space to support save/restore of the VGIC state.
> > 
> > This commit adds support only for the same logic as the current VGIC
> > support, and no more.  For example, the active priority registers are
> > handled as RAZ/WI, just like setting priorities on the emulated
> > distributor.
> > 
> > Signed-off-by: Christoffer Dall <[email-masked]>
> > ---
> > virt/kvm/arm/vgic.c |   66 +++++++++++++++++++++++++++++++++++++++++++++++----
> > 1 file changed, 62 insertions(+), 4 deletions(-)
> > 
> > diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
> > index d44b5a1..257dbae 100644
> > --- a/virt/kvm/arm/vgic.c
> > +++ b/virt/kvm/arm/vgic.c
> > @@ -1684,9 +1684,67 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
> > static bool handle_cpu_mmio_misc(struct kvm_vcpu *vcpu,
> > 				 struct kvm_exit_mmio *mmio, phys_addr_t offset)
> > {
> > -	return true;
> > +	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
> > +	u32 reg, mask = 0, shift = 0;
> > +	bool updated = false;
> > +
> > +	switch (offset & ~0x3) {
> > +	case GIC_CPU_CTRL:
> > +		mask = GICH_VMCR_CTRL_MASK;
> > +		shift = GICH_VMCR_CTRL_SHIFT;
> > +		break;
> > +	case GIC_CPU_PRIMASK:
> > +		mask = GICH_VMCR_PRIMASK_MASK;
> > +		shift = GICH_VMCR_PRIMASK_SHIFT;
> > +		break;
> > +	case GIC_CPU_BINPOINT:
> > +		mask = GICH_VMCR_BINPOINT_MASK;
> > +		shift = GICH_VMCR_BINPOINT_SHIFT;
> > +		break;
> > +	case GIC_CPU_ALIAS_BINPOINT:
> > +		mask = GICH_VMCR_ALIAS_BINPOINT_MASK;
> > +		shift = GICH_VMCR_ALIAS_BINPOINT_SHIFT;
> > +		break;
> > +	}
> > +
> > +	if (!mmio->is_write) {
> > +		reg = (vgic_cpu->vgic_vmcr & mask) >> shift;
> > +		memcpy(mmio->data, &reg, sizeof(reg));
> > +	} else {
> > +		memcpy(&reg, mmio->data, sizeof(reg));
> > +		reg = (reg << shift) & mask;
> > +		if (reg != (vgic_cpu->vgic_vmcr & mask))
> > +			updated = true;
> > +		vgic_cpu->vgic_vmcr &= ~mask;
> > +		vgic_cpu->vgic_vmcr |= reg;
> > +	}
> > +	return updated;
> > +}
> > +
> > +static bool handle_mmio_abpr(struct kvm_vcpu *vcpu,
> > +			     struct kvm_exit_mmio *mmio, phys_addr_t offset)
> > +{
> > +	return handle_cpu_mmio_misc(vcpu, mmio, GIC_CPU_ALIAS_BINPOINT);
> > +}
> > +
> > +static bool handle_cpu_mmio_ident(struct kvm_vcpu *vcpu,
> > +				  struct kvm_exit_mmio *mmio,
> > +				  phys_addr_t offset)
> > +{
> > +	u32 reg;
> > +
> > +	if (mmio->is_write)
> > +		return false;
> > +
> > +	reg = 0x0002043B;
> 
> This wants a comment and probably also a #define :).
> 

Marc, where does the 0x4b0 product id code come from for the distributor
IIDR?

Would this be satisfying?

diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 5214424..558be38 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -71,6 +71,9 @@
 #define VGIC_ADDR_UNDEF		(-1)
 #define IS_VGIC_ADDR_UNDEF(_x)  ((_x) == VGIC_ADDR_UNDEF)
 
+#define GIC_PRODUCT_ID		0x4b0
+#define ARM_JEP106_IMPLEMENTER	0x43b
+
 /* Physical address of vgic virtual cpu interface */
 static phys_addr_t vgic_vcpu_base;
 
@@ -331,7 +334,7 @@ static bool handle_mmio_misc(struct kvm_vcpu *vcpu,
 		break;
 
 	case 8:			/* IIDR */
-		reg = 0x4B00043B;
+		reg = (GIC_PRODUCT_ID << 20) | ARM_JEP106_IMPLEMENTER;
 		vgic_reg_access(mmio, &reg, word_offset,
 				ACCESS_READ_VALUE | ACCESS_WRITE_IGNORED);
 		break;
@@ -1734,7 +1737,7 @@ static bool handle_cpu_mmio_ident(struct kvm_vcpu *vcpu,
 	if (mmio->is_write)
 		return false;
 
-	reg = 0x0002043B;
+	reg = (GIC_PRODUCT_ID << 20) | (0x2 << 16) | ARM_JEP106_IMPLEMENTER;
 	mmio_data_write(mmio, ~0, reg);
 	return false;
 }

Thanks,
-Christoffer