[PATCH v4 3/4] KVM: arm64: Allow no running vcpu on restoring VGICv3 LPI pending status

Gavin Shan
2023-01-27T23:53:50Z

We don't have a running VCPU context to restore VGICv3 LPI pending status
due to command KVM_DEV_ARM_{VGIC_GRP_CTRL, ITS_RESTORE_TABLES} on KVM
device "kvm-arm-vgic-its".

Use vgic_write_guest_lock() to restore VGICv3 LPI pending status.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
---
Documentation/virt/kvm/api.rst | 8 +++++---
arch/arm64/kvm/vgic/vgic-v3.c | 2 +-
2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 9807b05a1b57..5dc3598afbe2 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -8070,9 +8070,11 @@ considering the state as complete. VMM needs to ensure that the dirty
state is final and avoid missing dirty pages from another ioctl ordered
after the bitmap collection.

-NOTE: One example of using the backup bitmap is saving arm64 vgic/its
-tables through KVM_DEV_ARM_{VGIC_GRP_CTRL, ITS_SAVE_TABLES} command on
-KVM device "kvm-arm-vgic-its" when dirty ring is enabled.
+NOTE: Multiple examples of using the backup bitmap: (1) save vgic/its
+tables through command KVM_DEV_ARM_{VGIC_GRP_CTRL, ITS_SAVE_TABLES} on
+KVM device "kvm-arm-vgic-its". (2) restore vgic/its tables through
+command KVM_DEV_ARM_{VGIC_GRP_CTRL, ITS_RESTORE_TABLES} on KVM device
+"kvm-arm-vgic-its". VGICv3 LPI pending status is restored.

8.30 KVM_CAP_XEN_HVM
--------------------
diff --git a/arch/arm64/kvm/vgic/vgic-v3.c b/arch/arm64/kvm/vgic/vgic-v3.c
index 5dfbd03e5e1a..c94e4d7520fc 100644
--- a/arch/arm64/kvm/vgic/vgic-v3.c
+++ b/arch/arm64/kvm/vgic/vgic-v3.c
@@ -338,7 +338,7 @@ int vgic_v3_lpi_sync_pending_status(struct kvm *kvm, struct vgic_irq *irq)
if (status) {
/* clear consumed data */
val &= ~(1 << bit_nr);
- ret = kvm_write_guest_lock(kvm, ptr, &val, 1);
+ ret = vgic_write_guest_lock(kvm, ptr, &val, 1);
if (ret)
return ret;
}
--
2.23.0