Hi Julien,
On 2019/12/28 16:09, Julien Grall wrote:
Hi,
On 28/12/2019 03:08, Wei Xu wrote:
This patch fixes the typo about the active status range of an IRQ
via GICD. Otherwise it will be failed to handle the mmio access and
inject a data abort.
I have seen a patch similar from NXP a month ago and I disagreed on
the approach.
If you look at the context you modifed, it says that reading ACTIVER
is not supported. While I agree the behavior is not consistent accross
ACTIVER, injecting a data abort is a perfectly fine behavior to me
(though not spec compliant) as we don't implement the registers
correctly.
I guess you are sending this patch, because you tried Linux 5.4 (or
later) on Xen, right? Linux has recently began to read ACTIVER to
check whether an IRQ is active at the HW level during the
synchronizing of the IRQS. From my understanding, this is used because
there is a window where the interrupt is active at the HW level but
the Linux IRQ subsystem is not aware of it.
While the patch below will allow Linux 5.4 to not crash, it is not
going to make it fly very far because of the above. So I am rather not
happy with persuing with returning 0.
Yes, I am using Linux 5.5-rc2 :)
Got it and thanks for the explanation.
I am not insistent on this and OK to wait for the update.
Thanks and have a very happy new year!
Best Regards,
Wei
@Stefano, you mention you will look at implementing ACTIVER. What's
the state?
>
Fixes: a2b83f95bfad ("xen/arm: vgic: Properly emulate the full
register")
Signed-off-by: Wei Xu <xuw...@hisilicon.com>
---
xen/arch/arm/vgic-v3.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c
index 422b94f..e802f20 100644
--- a/xen/arch/arm/vgic-v3.c
+++ b/xen/arch/arm/vgic-v3.c
@@ -706,7 +706,7 @@ static int __vgic_v3_distr_common_mmio_read(const
char *name, struct vcpu *v,
goto read_as_zero;
/* Read the active status of an IRQ via GICD/GICR is not
supported */
- case VRANGE32(GICD_ISACTIVER, GICD_ISACTIVER):
+ case VRANGE32(GICD_ISACTIVER, GICD_ISACTIVERN):
case VRANGE32(GICD_ICACTIVER, GICD_ICACTIVERN):
goto read_as_zero;
Cheers,
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