Re: [Xen-devel] [PATCH v4 08/28] x86/vvtd: Add MMIO handler for VVTD

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Fri, Nov 17, 2017 at 02:22:15PM +0800, Chao Gao wrote:
> This patch adds VVTD MMIO handler to deal with MMIO access.
> 
> Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
> Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
> ---
> v4:
>  - only trap the register emulated in vvtd_in_range().
>    i.e. replace PAGE_SIZE with the VVTD_MAX_OFFSET
> ---
>  xen/drivers/passthrough/vtd/vvtd.c | 55 
> ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 55 insertions(+)
> 
> diff --git a/xen/drivers/passthrough/vtd/vvtd.c 
> b/xen/drivers/passthrough/vtd/vvtd.c
> index 9f76ccf..d78d878 100644
> --- a/xen/drivers/passthrough/vtd/vvtd.c
> +++ b/xen/drivers/passthrough/vtd/vvtd.c

Now that I look at this, this is the wrong folder. This should be in
xen/arch/x86/hvm with the rest of the emulated devices.

> @@ -94,6 +94,60 @@ static inline uint64_t vvtd_get_reg_quad(const struct vvtd 
> *vvtd, uint32_t reg)
>      return *(uint64_t*)VVTD_REG_POS(vvtd, reg);
>  }
>  
> +static void *domain_vvtd(const struct domain *d)
> +{
> +    if ( is_hvm_domain(d) && d->arch.hvm_domain.viommu )

hvm_mmio_ops is only used by HVM guests, so the is_hvm_domain check
here is redundant. At which point the helper can be simplified as:

static struct vvtd *domain_vvtd(const struct domain *d)
{
    return d->arch.hvm_domain.viommu ? d->arch.hvm_domain.viommu->priv : NULL;
}

> +        return d->arch.hvm_domain.viommu->priv;
> +    else
> +        return NULL;
> +}
> +
> +static int vvtd_in_range(struct vcpu *v, unsigned long addr)
> +{
> +    struct vvtd *vvtd = domain_vvtd(v->domain);
const

> +
> +    if ( vvtd )
> +        return (addr >= vvtd->base_addr) &&
> +               (addr < vvtd->base_addr + VVTD_MAX_OFFSET);
> +    return 0;
> +}
> +
> +static int vvtd_read(struct vcpu *v, unsigned long addr,
> +                     unsigned int len, unsigned long *pval)
> +{
> +    struct vvtd *vvtd = domain_vvtd(v->domain);
const

Thanks, Roger.

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