Re: [Xen-devel] [PATCH v2 09/17] arm64: vgic-v3: Add ICV_HPPIR1_EL1 handler

[Manish Jaggi <mjaggi@xxxxxxxxxxxxxxxxxx>]

On 03/27/2018 04:26 PM, Marc Zyngier wrote:
> On 27/03/18 10:07, Manish Jaggi wrote:
> > This patch is ported from linux to xen
> > commit: 2724c11a1df4b22ee966c04809ea0e808f66b04e
> > (KVM: arm64: vgic-v3: Add ICV_HPPIR1_EL1 handler)
> >
> > Add a handler for reading the guest's view of the ICV_HPPIR1_EL1
> > register. This is a simple parsing of the available LRs, extracting the
> > highest available interrupt.
> >
> > Signed-off-by: Manish Jaggi <manish.jaggi@xxxxxxxxxx>
> > ---
> >   xen/arch/arm/arm64/vgic-v3-sr.c     | 31 +++++++++++++++++++++++++++++++
> >   xen/include/asm-arm/arm64/sysregs.h |  1 +
> >   2 files changed, 32 insertions(+)
> >
> > diff --git a/xen/arch/arm/arm64/vgic-v3-sr.c b/xen/arch/arm/arm64/vgic-v3-sr.c
> > index c67e7c6ada..f11c7646da 100644
> > --- a/xen/arch/arm/arm64/vgic-v3-sr.c
> > +++ b/xen/arch/arm/arm64/vgic-v3-sr.c
> > @@ -674,6 +674,33 @@ static void vreg_emulate_apxr3(struct cpu_user_regs *regs,
> >           vgic_v3_write_apxrn(regs, hsr, 3);
> >   }
> >   
> > +static void vgic_v3_read_hppir1(struct cpu_user_regs *regs,
> > +                                const union hsr hsr)
> > +{
> > +    uint64_t lr_val;
> > +    int lr, lr_grp, grp;
> > +    uint32_t vmcr = READ_SYSREG32(ICH_VMCR_EL2);
> > +
> > +    grp = vgic_v3_get_group(hsr);
> > +    lr = vgic_v3_highest_priority_lr(regs, vmcr, &lr_val);
> > +
> > +    if ( lr == -1 )
> > +        goto spurious;
> > +
> > +    lr_grp = !!(lr_val & ICH_LR_GROUP);
> > +    if ( lr_grp != grp )
> > +        lr_val = ICC_IAR1_EL1_SPURIOUS;
> > +
> > +spurious:
> > +    set_user_reg(regs, hsr.sysreg.reg, lr_val & ICH_LR_VIRTUAL_ID_MASK);
> > +}
> > +
> > +static void vreg_emulate_hppir1(struct cpu_user_regs *regs,
> > +                                const union hsr hsr)
> > +{
> > +    vgic_v3_read_hppir1(regs, hsr);
> > +}
> See why I said that this "emulate" function idea didn't hold much water?
I wanted to put a check for read call, but I was just trying to match 
the patch,
So that a later patch would inject an undef exception to guest if a 
write is issue by guest on hppir1
>         M.

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