From: Andre Przywara Date: Fri, 9 Mar 2018 15:11:17 +0000 (+0000) Subject: ARM: vGICv3: clarify on GUEST_GICV3_RDIST_REGIONS symbol X-Git-Tag: archive/raspbian/4.11.1-1+rpi1~1^2~66^2~432 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=2bb950b8d911d7ec104144fc43b48c7a0d90583a;p=xen.git ARM: vGICv3: clarify on GUEST_GICV3_RDIST_REGIONS symbol Normally there is only one GICv3 redistributor region, and we use that for DomU guests using a GICv3. Explain the background in a comment and why we need to keep the number of hardware regions for Dom0. Signed-off-by: Andre Przywara Acked-by: Julien Grall --- diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c index 2ad8a6be62..d5b34a7d0f 100644 --- a/xen/arch/arm/vgic-v3.c +++ b/xen/arch/arm/vgic-v3.c @@ -1632,6 +1632,16 @@ static int vgic_v3_vcpu_init(struct vcpu *v) static inline unsigned int vgic_v3_rdist_count(struct domain *d) { + /* + * Normally there is only one GICv3 redistributor region. + * The GICv3 DT binding provisions for multiple regions, since there are + * platforms out there which need those (multi-socket systems). + * For Dom0 we have to live with the MMIO layout the hardware provides, + * so we have to copy the multiple regions - as the first region may not + * provide enough space to hold all redistributors we need. + * However DomU get a constructed memory map, so we can go with + * the architected single redistributor region. + */ return is_hardware_domain(d) ? vgic_v3_hw.nr_rdist_regions : GUEST_GICV3_RDIST_REGIONS; } @@ -1692,7 +1702,7 @@ static int vgic_v3_domain_init(struct domain *d) { d->arch.vgic.dbase = GUEST_GICV3_GICD_BASE; - /* XXX: Only one Re-distributor region mapped for the guest */ + /* A single Re-distributor region is mapped for the guest. */ BUILD_BUG_ON(GUEST_GICV3_RDIST_REGIONS != 1); d->arch.vgic.rdist_stride = GUEST_GICV3_RDIST_STRIDE;