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authorChristoffer Dall <christoffer.dall@linaro.org>2017-01-23 16:07:18 +0300
committerChristoffer Dall <christoffer.dall@linaro.org>2017-01-25 15:26:13 +0300
commit8694e4da66a636665f51b94a6a7a40c9fc0dc5ec (patch)
tree6b0996de643155a1038800787afe7b700e88de45 /virt/kvm/arm/vgic/vgic-v2.c
parent7a308bb3016f57e5be11a677d15b821536419d36 (diff)
downloadlinux-8694e4da66a636665f51b94a6a7a40c9fc0dc5ec.tar.xz
KVM: arm/arm64: Remove struct vgic_irq pending field
One of the goals behind the VGIC redesign was to get rid of cached or intermediate state in the data structures, but we decided to allow ourselves to precompute the pending value of an IRQ based on the line level and pending latch state. However, this has now become difficult to base proper GICv3 save/restore on, because there is a potential to modify the pending state without knowing if an interrupt is edge or level configured. See the following post and related message for more background: https://lists.cs.columbia.edu/pipermail/kvmarm/2017-January/023195.html This commit gets rid of the precomputed pending field in favor of a function that calculates the value when needed, irq_is_pending(). The soft_pending field is renamed to pending_latch to represent that this latch is the equivalent hardware latch which gets manipulated by the input signal for edge-triggered interrupts and when writing to the SPENDR/CPENDR registers. After this commit save/restore code should be able to simply restore the pending_latch state, line_level state, and config state in any order and get the desired result. Reviewed-by: Andre Przywara <andre.przywara@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Tested-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'virt/kvm/arm/vgic/vgic-v2.c')
-rw-r--r--virt/kvm/arm/vgic/vgic-v2.c12
1 files changed, 5 insertions, 7 deletions
diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c
index 834137e7b83f..b834ecdf3225 100644
--- a/virt/kvm/arm/vgic/vgic-v2.c
+++ b/virt/kvm/arm/vgic/vgic-v2.c
@@ -104,7 +104,7 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu)
/* Edge is the only case where we preserve the pending bit */
if (irq->config == VGIC_CONFIG_EDGE &&
(val & GICH_LR_PENDING_BIT)) {
- irq->pending = true;
+ irq->pending_latch = true;
if (vgic_irq_is_sgi(intid)) {
u32 cpuid = val & GICH_LR_PHYSID_CPUID;
@@ -120,9 +120,7 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu)
*/
if (irq->config == VGIC_CONFIG_LEVEL) {
if (!(val & GICH_LR_PENDING_BIT))
- irq->soft_pending = false;
-
- irq->pending = irq->line_level || irq->soft_pending;
+ irq->pending_latch = false;
}
spin_unlock(&irq->irq_lock);
@@ -145,11 +143,11 @@ void vgic_v2_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr)
{
u32 val = irq->intid;
- if (irq->pending) {
+ if (irq_is_pending(irq)) {
val |= GICH_LR_PENDING_BIT;
if (irq->config == VGIC_CONFIG_EDGE)
- irq->pending = false;
+ irq->pending_latch = false;
if (vgic_irq_is_sgi(irq->intid)) {
u32 src = ffs(irq->source);
@@ -158,7 +156,7 @@ void vgic_v2_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr)
val |= (src - 1) << GICH_LR_PHYSID_CPUID_SHIFT;
irq->source &= ~(1 << (src - 1));
if (irq->source)
- irq->pending = true;
+ irq->pending_latch = true;
}
}