On Wed, 2015-11-25 at 12:15 +0000, Stefano Stabellini wrote: > Hi Shannon, > > On Wed, 25 Nov 2015, Shannon Zhao wrote: > > Upstream Linux kernel applies below patch which will write > > GICD_ICACTIVER. But since Xen doesn't support it, so it will cause Dom0 > > initializes GIC failed. > > > > 0eece2b22849c90b730815c893425a36b9d10fd5 (irqchip/gic: Make sure all > > interrupts are deactivated at boot) > > > > (XEN) d0v0: vGICD: unhandled word write 0xffffffff to ICACTIVER4 > > (XEN) traps.c:2447:d0v0 HSR=0x93860046 pc=0xffffffc0008d63f0 > > gva=0xffffff8000004384 gpa=0x0000002f000384 > > (XEN) DOM0: Unhandled fault: ttbr address size fault (0x96000000) at > > 0xffffff8000004384 > > (XEN) DOM0: Internal error: : 96000000 [#1] PREEMPT SMP > > (XEN) DOM0: Modules linked in: > > (XEN) DOM0: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.0-rc2+ #364 > > (XEN) DOM0: Hardware name: (null) (DT) > > (XEN) DOM0: task: ffffffc000969970 ti: ffffffc00095c000 task.ti: > > ffffffc00095c000 > > (XEN) DOM0: PC is at gic_dist_config+0x78/0xa0 > > (XEN) DOM0: LR is at __gic_init_bases+0x240/0x2bc > > > > Do we have a plan to fix this? > > Thanks for the reporting the issue, I can reproduce the problem. Given > that this is a very serious regression and that we cannot really "fix" > the Linux side because Linux is not doing anything wrong, I think we > have to go with a very simple change, something we can easily backport > to all past Xen releases. > > I suggest we turn the "unhandled word write" into a write_ignore, see > below:
As discussed IRL this might be tolerable as a patch intended for backporting purposes, but I would want to see it in a series along with one or more not-for-backport patches which actually makes the register work as it should. > > --- > > xen/arm: ignore GICD_ICACTIVER writes > > Signed-off-by: Stefano Stabellini <stefano.stabell...@eu.citrix.com> > > diff --git a/xen/arch/arm/vgic-v2.c b/xen/arch/arm/vgic-v2.c > index f7d784b..8585c44 100644 > --- a/xen/arch/arm/vgic-v2.c > +++ b/xen/arch/arm/vgic-v2.c > @@ -332,11 +332,8 @@ static int vgic_v2_distr_mmio_write(struct vcpu *v, > mmio_info_t *info, > return 0; > > case GICD_ICACTIVER ... GICD_ICACTIVERN: > - if ( dabt.size != DABT_WORD ) goto bad_width; > - printk(XENLOG_G_ERR > - "%pv: vGICD: unhandled word write %#"PRIregister" to > ICACTIVER%d\n", > - v, r, gicd_reg - GICD_ICACTIVER); > - return 0; > + /* we should really be implementing this */ > + goto write_ignore_32; > > case GICD_ITARGETSR ... GICD_ITARGETSR + 7: > /* SGI/PPI target is read only */ > diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c > index b5249ff..6d77373 100644 > --- a/xen/arch/arm/vgic-v3.c > +++ b/xen/arch/arm/vgic-v3.c > @@ -421,11 +421,8 @@ static int __vgic_v3_distr_common_mmio_write(const > char *name, struct vcpu *v, > return 0; > > case GICD_ICACTIVER ... GICD_ICACTIVERN: > - if ( dabt.size != DABT_WORD ) goto bad_width; > - printk(XENLOG_G_ERR > - "%pv: %s: unhandled word write %#"PRIregister" to > ICACTIVER%d\n", > - v, name, r, reg - GICD_ICACTIVER); > - return 0; > + /* we should really be implementing this */ > + goto write_ignore_32; > > case GICD_IPRIORITYR ... GICD_IPRIORITYRN: > if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto > bad_width; _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
