[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen master] xen/arm: clear UIE on hypervisor entry
commit 31180f87e4f7f63e3bca029b4a60978f57eb0331 Author: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> AuthorDate: Fri Nov 21 14:31:30 2014 +0000 Commit: Ian Campbell <ian.campbell@xxxxxxxxxx> CommitDate: Tue Nov 25 14:08:01 2014 +0000 xen/arm: clear UIE on hypervisor entry UIE being set can cause maintenance interrupts to occur when Xen writes to one or more LR registers. The effect is a busy loop around the interrupt handler in Xen (http://marc.info/?l=xen-devel&m=141597517132682): everything gets stuck. Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx> Reported-and-Tested-by: Andrii Tseglytskyi <andrii.tseglytskyi@xxxxxxxxxxxxxxx> Tested-by: Julien Grall <julien.grall@xxxxxxxxxx> Release-acked-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> --- xen/arch/arm/gic.c | 9 +++++++-- 1 files changed, 7 insertions(+), 2 deletions(-) diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c index 70d10d6..e7a1af5 100644 --- a/xen/arch/arm/gic.c +++ b/xen/arch/arm/gic.c @@ -403,6 +403,8 @@ void gic_clear_lrs(struct vcpu *v) if ( is_idle_vcpu(v) ) return; + gic_hw_ops->update_hcr_status(GICH_HCR_UIE, 0); + spin_lock_irqsave(&v->arch.vgic.lock, flags); while ((i = find_next_bit((const unsigned long *) &this_cpu(lr_mask), @@ -527,8 +529,6 @@ void gic_inject(void) if ( !list_empty(¤t->arch.vgic.lr_pending) && lr_all_full() ) gic_hw_ops->update_hcr_status(GICH_HCR_UIE, 1); - else - gic_hw_ops->update_hcr_status(GICH_HCR_UIE, 0); } static void do_sgi(struct cpu_user_regs *regs, enum gic_sgi sgi) @@ -598,6 +598,11 @@ static void maintenance_interrupt(int irq, void *dev_id, struct cpu_user_regs *r * Receiving the interrupt is going to cause gic_inject to be called * on return to guest that is going to clear the old LRs and inject * new interrupts. + * + * Do not add code here: maintenance interrupts caused by setting + * GICH_HCR_UIE, might read as spurious interrupts (1023) because + * GICH_HCR_UIE is cleared before reading GICC_IAR. As a consequence + * this handler is not called. */ } -- generated by git-patchbot for /home/xen/git/xen.git#master _______________________________________________ Xen-changelog mailing list Xen-changelog@xxxxxxxxxxxxx http://lists.xensource.com/xen-changelog
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