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arm: Make sure not to shift off of the end of a uint32_t in KVM.

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The methods which set or get an attribute from the virtual GIC use a
shift constant which is 32, but they store their result in a 32 bit
variable and, according to clang, are used to shift 32 bit inputs. This
is undefined behavior in terms of the shift, and will truncate off the
value regardless.

Change-Id: Ie9543ab9e6e1d5f86317a9210d220928b23ffaf8
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/23129
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Ciro Santilli <ciro.santilli@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
This commit is contained in:
Gabe Black
2019-11-27 04:55:13 -08:00
parent 2a0140593f
commit ddcc0ab2b4
1 changed files with 4 additions and 4 deletions
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8
src/arch/arm/kvm/gic.cc
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@@ -115,8 +115,8 @@ KvmKernelGicV2::getGicReg(unsigned group, unsigned vcpu, unsigned offset)
uint64_t reg;
assert(vcpu <= KVM_ARM_IRQ_VCPU_MASK);
const uint32_t attr(
(vcpu << KVM_DEV_ARM_VGIC_CPUID_SHIFT) |
const uint64_t attr(
((uint64_t)vcpu << KVM_DEV_ARM_VGIC_CPUID_SHIFT) |
(offset << KVM_DEV_ARM_VGIC_OFFSET_SHIFT));
kdev.getAttrPtr(group, attr, &reg);
@@ -130,8 +130,8 @@ KvmKernelGicV2::setGicReg(unsigned group, unsigned vcpu, unsigned offset,
uint64_t reg = value;
assert(vcpu <= KVM_ARM_IRQ_VCPU_MASK);
const uint32_t attr(
(vcpu << KVM_DEV_ARM_VGIC_CPUID_SHIFT) |
const uint64_t attr(
((uint64_t)vcpu << KVM_DEV_ARM_VGIC_CPUID_SHIFT) |
(offset << KVM_DEV_ARM_VGIC_OFFSET_SHIFT));
kdev.setAttrPtr(group, attr, &reg);