This patch adds a new attribute to GICV3 KVM device
KVM_DEV_ARM_VGIC_GRP_CTRL group. This allows userspace to
flush all GICR pending tables into guest RAM.

Signed-off-by: Eric Auger <[email protected]>
Reviewed-by: Christoffer Dall <[email protected]>

---
v6 -> v7:
- remove GICR_PENDBASER_ADDRESS
- added Christoffer's R-b

v5 -> v6:
- fix stored
- GICR_PEND/PROPBASER_ADDRESS were already introduced

v4 -> v5:
- move pending table save code/ctrl into VGICv3 instead of ITS
- remove useless gpa_t cast
- use the same optimization as in its_sync_lpi_pending_table

v3 -> v4:
- remove the wrong comment about locking
- pass kvm struct instead of its handle
- add comment about restore method
- remove GITR_PENDABASER.PTZ check
- continue if target_vcpu == NULL
- new locking strategy

v1 -> v2:
- do not care about the 1st KB which should be zeroed according to
  the spec.
---
 arch/arm/include/uapi/asm/kvm.h     |  1 +
 arch/arm64/include/uapi/asm/kvm.h   |  1 +
 virt/kvm/arm/vgic/vgic-kvm-device.c | 20 +++++++++++++++
 virt/kvm/arm/vgic/vgic-v3.c         | 51 +++++++++++++++++++++++++++++++++++++
 virt/kvm/arm/vgic/vgic.h            |  1 +
 5 files changed, 74 insertions(+)

diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
index 8e6563c..78fe803 100644
--- a/arch/arm/include/uapi/asm/kvm.h
+++ b/arch/arm/include/uapi/asm/kvm.h
@@ -202,6 +202,7 @@ struct kvm_arch_memory_slot {
 #define   KVM_DEV_ARM_VGIC_CTRL_INIT           0
 #define   KVM_DEV_ARM_ITS_SAVE_TABLES          1
 #define   KVM_DEV_ARM_ITS_RESTORE_TABLES       2
+#define   KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES 3
 
 /* KVM_IRQ_LINE irq field index values */
 #define KVM_ARM_IRQ_TYPE_SHIFT         24
diff --git a/arch/arm64/include/uapi/asm/kvm.h 
b/arch/arm64/include/uapi/asm/kvm.h
index 1e35115..8a3758a 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -222,6 +222,7 @@ struct kvm_arch_memory_slot {
 #define   KVM_DEV_ARM_VGIC_CTRL_INIT           0
 #define   KVM_DEV_ARM_ITS_SAVE_TABLES           1
 #define   KVM_DEV_ARM_ITS_RESTORE_TABLES        2
+#define   KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES 3
 
 /* Device Control API on vcpu fd */
 #define KVM_ARM_VCPU_PMU_V3_CTRL       0
diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c 
b/virt/kvm/arm/vgic/vgic-kvm-device.c
index 859bfa8..d48743c 100644
--- a/virt/kvm/arm/vgic/vgic-kvm-device.c
+++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
@@ -580,6 +580,24 @@ static int vgic_v3_set_attr(struct kvm_device *dev,
                reg = tmp32;
                return vgic_v3_attr_regs_access(dev, attr, &reg, true);
        }
+       case KVM_DEV_ARM_VGIC_GRP_CTRL: {
+               int ret;
+
+               switch (attr->attr) {
+               case KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES:
+                       mutex_lock(&dev->kvm->lock);
+
+                       if (!lock_all_vcpus(dev->kvm)) {
+                               mutex_unlock(&dev->kvm->lock);
+                               return -EBUSY;
+                       }
+                       ret = vgic_v3_save_pending_tables(dev->kvm);
+                       unlock_all_vcpus(dev->kvm);
+                       mutex_unlock(&dev->kvm->lock);
+                       return ret;
+               }
+               break;
+       }
        }
        return -ENXIO;
 }
@@ -658,6 +676,8 @@ static int vgic_v3_has_attr(struct kvm_device *dev,
                switch (attr->attr) {
                case KVM_DEV_ARM_VGIC_CTRL_INIT:
                        return 0;
+               case KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES:
+                       return 0;
                }
        }
        return -ENXIO;
diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
index 0d753ae..6ff6510 100644
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -296,6 +296,57 @@ int vgic_v3_lpi_sync_pending_status(struct kvm *kvm, 
struct vgic_irq *irq)
        return 0;
 }
 
+/**
+ * vgic_its_save_pending_tables - Save the pending tables into guest RAM
+ * kvm lock and all vcpu lock must be held
+ */
+int vgic_v3_save_pending_tables(struct kvm *kvm)
+{
+       struct vgic_dist *dist = &kvm->arch.vgic;
+       int last_byte_offset = -1;
+       struct vgic_irq *irq;
+       int ret;
+
+       list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
+               int byte_offset, bit_nr;
+               struct kvm_vcpu *vcpu;
+               gpa_t pendbase, ptr;
+               bool stored;
+               u8 val;
+
+               vcpu = irq->target_vcpu;
+               if (!vcpu)
+                       continue;
+
+               pendbase = 
GICR_PENDBASER_ADDRESS(vcpu->arch.vgic_cpu.pendbaser);
+
+               byte_offset = irq->intid / BITS_PER_BYTE;
+               bit_nr = irq->intid % BITS_PER_BYTE;
+               ptr = pendbase + byte_offset;
+
+               if (byte_offset != last_byte_offset) {
+                       ret = kvm_read_guest(kvm, ptr, &val, 1);
+                       if (ret)
+                               return ret;
+                       last_byte_offset = byte_offset;
+               }
+
+               stored = val & (1U << bit_nr);
+               if (stored == irq->pending_latch)
+                       continue;
+
+               if (irq->pending_latch)
+                       val |= 1 << bit_nr;
+               else
+                       val &= ~(1 << bit_nr);
+
+               ret = kvm_write_guest(kvm, ptr, &val, 1);
+               if (ret)
+                       return ret;
+       }
+       return 0;
+}
+
 /* check for overlapping regions and for regions crossing the end of memory */
 static bool vgic_v3_check_base(struct kvm *kvm)
 {
diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index 92a8ca0..8de59a4 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -181,6 +181,7 @@ void vgic_v3_enable(struct kvm_vcpu *vcpu);
 int vgic_v3_probe(const struct gic_kvm_info *info);
 int vgic_v3_map_resources(struct kvm *kvm);
 int vgic_v3_lpi_sync_pending_status(struct kvm *kvm, struct vgic_irq *irq);
+int vgic_v3_save_pending_tables(struct kvm *kvm);
 int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t dist_base_address);
 
 int vgic_register_its_iodevs(struct kvm *kvm);
-- 
2.5.5

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