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Subject[PATCH v6 3/9] KVM: arm/arm64: vgic-its: Check CBASER/BASER validity before enabling the ITS
Date
The spec says it is UNPREDICTABLE to enable the ITS
if any of the following conditions are true:

- GITS_CBASER.Valid == 0.
- GITS_BASER<n>.Valid == 0, for any GITS_BASER<n> register
where the Type field indicates Device.
- GITS_BASER<n>.Valid == 0, for any GITS_BASER<n> register
where the Type field indicates Interrupt Collection and
GITS_TYPER.HCC == 0.

In that case, let's keep the ITS disabled.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reported-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>

---

v5 -> v6:
- added Christoffer's R-b

v4 -> v5:
- check the condition before updating its->enabled and
fix its->cbaser && GITS_CBASER_VALID

v3: creation
---
virt/kvm/arm/vgic/vgic-its.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 8230ffe..c4758e6 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -1466,6 +1466,16 @@ static void vgic_mmio_write_its_ctlr(struct kvm *kvm, struct vgic_its *its,
{
mutex_lock(&its->cmd_lock);

+ /*
+ * It is UNPREDICTABLE to enable the ITS if any of the CBASER or
+ * device/collection BASER are invalid
+ */
+ if (!its->enabled && (val & GITS_CTLR_ENABLE) &&
+ (!(its->baser_device_table & GITS_BASER_VALID) ||
+ !(its->baser_coll_table & GITS_BASER_VALID) ||
+ !(its->cbaser & GITS_CBASER_VALID)))
+ goto out;
+
its->enabled = !!(val & GITS_CTLR_ENABLE);

/*
@@ -1474,6 +1484,7 @@ static void vgic_mmio_write_its_ctlr(struct kvm *kvm, struct vgic_its *its,
*/
vgic_its_process_commands(kvm, its);

+out:
mutex_unlock(&its->cmd_lock);
}

--
2.5.5
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