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KVM: arm/arm64: vgic: Fix GICC_PMR uaccess on GICv3 and clarify ABI

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As an oversight, for GICv2, we accidentally export the GICC_PMR register
in the format of the GICH_VMCR.VMPriMask field in the lower 5 bits of a
word, meaning that userspace must always use the lower 5 bits to
communicate with the KVM device and must shift the value left by 3
places to obtain the actual priority mask level.

Since GICv3 supports the full 8 bits of priority masking in the ICH_VMCR,
we have to fix the value we export when emulating a GICv2 on top of a
hardware GICv3 and exporting the emulated GICv2 state to userspace.

Take the chance to clarify this aspect of the ABI.

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
This commit is contained in:
Christoffer Dall
2017-03-21 22:05:22 +01:00
parent 5b0d2cc280
commit 6d56111c92
5 changed files with 39 additions and 7 deletions
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3
include/linux/irqchip/arm-gic.h
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@@ -96,6 +96,9 @@
#define GICH_MISR_EOI (1 << 0)
#define GICH_MISR_U (1 << 1)
#define GICV_PMR_PRIORITY_SHIFT 3
#define GICV_PMR_PRIORITY_MASK (0x1f << GICV_PMR_PRIORITY_SHIFT)
#ifndef __ASSEMBLY__
#include <linux/irqdomain.h>