Subject: [PATCH v3 24/55] KVM: arm/arm64: vgic-new: Add ENABLE registers handlers

From: [email-masked] (Christoffer Dall)
Date: Wed, 11 May 2016 15:47:25 +0200

On Wed, May 11, 2016 at 02:13:48PM +0100, Marc Zyngier wrote:
> On 11/05/16 13:34, Christoffer Dall wrote:
> > On Fri, May 06, 2016 at 11:45:37AM +0100, Andre Przywara wrote:
> >> As the enable register handlers are shared between the v2 and v3
> >> emulation, their implementation goes into vgic-mmio.c, to be easily
> >> referenced from the v3 emulation as well later.
> >>
> >> Signed-off-by: Andre Przywara <[email-masked]>
> >> ---
> >> Changelog RFC..v1:
> >> - use lower bits of address to determine IRQ number
> >> - remove TODO, confirmed to be fine
> >>
> >> Changelog v1 .. v2:
> >> - adapt to new MMIO framework
> >>
> >>  virt/kvm/arm/vgic/vgic-mmio-v2.c |  4 +--
> >>  virt/kvm/arm/vgic/vgic-mmio.c    | 56 ++++++++++++++++++++++++++++++++++++++++
> >>  virt/kvm/arm/vgic/vgic-mmio.h    | 11 ++++++++
> >>  3 files changed, 69 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c
> >> index 69e96f7..448d1da 100644
> >> --- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
> >> +++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c
> >> @@ -72,9 +72,9 @@ static const struct vgic_register_region vgic_v2_dist_registers[] = {
> >>  	REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_IGROUP,
> >>  		vgic_mmio_read_rao, vgic_mmio_write_wi, 1),
> >>  	REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_ENABLE_SET,
> >> -		vgic_mmio_read_raz, vgic_mmio_write_wi, 1),
> >> +		vgic_mmio_read_enable, vgic_mmio_write_senable, 1),
> >>  	REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_ENABLE_CLEAR,
> >> -		vgic_mmio_read_raz, vgic_mmio_write_wi, 1),
> >> +		vgic_mmio_read_enable, vgic_mmio_write_cenable, 1),
> >>  	REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_PENDING_SET,
> >>  		vgic_mmio_read_raz, vgic_mmio_write_wi, 1),
> >>  	REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_PENDING_CLEAR,
> >> diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
> >> index 41cf4f4..077ae86 100644
> >> --- a/virt/kvm/arm/vgic/vgic-mmio.c
> >> +++ b/virt/kvm/arm/vgic/vgic-mmio.c
> >> @@ -46,6 +46,62 @@ void vgic_mmio_write_wi(struct kvm_vcpu *vcpu, gpa_t addr,
> >>  	/* Ignore */
> >>  }
> >>  
> >> +/*
> >> + * Read accesses to both GICD_ICENABLER and GICD_ISENABLER return the value
> >> + * of the enabled bit, so there is only one function for both here.
> >> + */
> >> +unsigned long vgic_mmio_read_enable(struct kvm_vcpu *vcpu,
> >> +				    gpa_t addr, unsigned int len)
> >> +{
> >> +	u32 intid = (addr & 0x7f) * 8;
> > 
> > is there anything we can do about this to make it more intuitive?  A
> > macro to generate the mask/offset based on bits per interrupt or
> > something?
> 
> Untested (and thus probably wrong):
> 
> #define VGIC_ADDR_IRQ_MASK(bits) ((1024 - 1) >> (4 - (bits))

you're going to have to explain this to me, where is the (4 - bits)
coming from?

> #define VGIC_ADDR_IRQ_MULT(bits) (8 / (bits))
> #define VGIC_ADDR_TO_INTID(addr, bits)  (((addr) & VGIC_ADDR_IRQ_MASK(bits)) * \
> 					 VGIC_ADDR_IRQ_MULT(bits))

> 
> 	u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
> 
> Thanks,
> 
> 	M.
> -- 
> Jazz is not dead. It just smells funny...