KVM: arm/arm64: vgic-its: Implement KVM_DEV_ARM_ITS_CTRL_RESET

On reset we clear the valid bits of GITS_CBASER and GITS_BASER<n>.
We also clear command queue registers and free the cache (device,
collection, and lpi lists).

As we need to take the same locks as save/restore functions, we
create a vgic_its_ctrl() wrapper that handles KVM_DEV_ARM_VGIC_GRP_CTRL
group functions.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

3 files changed, 58 insertions, 49 deletions

diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
index 665c454e50d0..b56895593c84 100644
--- a/arch/arm/include/uapi/asm/kvm.h
+++ b/arch/arm/include/uapi/asm/kvm.h
@@ -221,6 +221,7 @@ struct kvm_arch_memory_slot {
 #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
+#define   KVM_DEV_ARM_ITS_CTRL_RESET            4
 
 /* 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 0004feef7cc2..37ca7394549c 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -233,6 +233,7 @@ struct kvm_arch_memory_slot {
 #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
+#define   KVM_DEV_ARM_ITS_CTRL_RESET            4
 
 /* Device Control API on vcpu fd */
 #define KVM_ARM_VCPU_PMU_V3_CTRL        0
diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 1732e08a4375..40791c121710 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -2273,29 +2273,13 @@ static int vgic_its_restore_collection_table(struct vgic_its *its)
  */
 static int vgic_its_save_tables_v0(struct vgic_its *its)
 {
-        struct kvm *kvm = its->dev->kvm;
         int ret;
 
-        mutex_lock(&kvm->lock);
-        mutex_lock(&its->its_lock);
-
-        if (!lock_all_vcpus(kvm)) {
-                mutex_unlock(&its->its_lock);
-                mutex_unlock(&kvm->lock);
-                return -EBUSY;
-        }
-
         ret = vgic_its_save_device_tables(its);
         if (ret)
-                goto out;
-
-        ret = vgic_its_save_collection_table(its);
+                return ret;
 
-out:
-        unlock_all_vcpus(kvm);
-        mutex_unlock(&its->its_lock);
-        mutex_unlock(&kvm->lock);
-        return ret;
+        return vgic_its_save_collection_table(its);
 }
 
 /**
@@ -2305,29 +2289,13 @@ out:
  */
 static int vgic_its_restore_tables_v0(struct vgic_its *its)
 {
-        struct kvm *kvm = its->dev->kvm;
         int ret;
 
-        mutex_lock(&kvm->lock);
-        mutex_lock(&its->its_lock);
-
-        if (!lock_all_vcpus(kvm)) {
-                mutex_unlock(&its->its_lock);
-                mutex_unlock(&kvm->lock);
-                return -EBUSY;
-        }
-
         ret = vgic_its_restore_collection_table(its);
         if (ret)
-                goto out;
-
-        ret = vgic_its_restore_device_tables(its);
-out:
-        unlock_all_vcpus(kvm);
-        mutex_unlock(&its->its_lock);
-        mutex_unlock(&kvm->lock);
+                return ret;
 
-        return ret;
+        return vgic_its_restore_device_tables(its);
 }
 
 static int vgic_its_commit_v0(struct vgic_its *its)
@@ -2346,6 +2314,19 @@ static int vgic_its_commit_v0(struct vgic_its *its)
         return 0;
 }
 
+static void vgic_its_reset(struct kvm *kvm, struct vgic_its *its)
+{
+        /* We need to keep the ABI specific field values */
+        its->baser_coll_table &= ~GITS_BASER_VALID;
+        its->baser_device_table &= ~GITS_BASER_VALID;
+        its->cbaser = 0;
+        its->creadr = 0;
+        its->cwriter = 0;
+        its->enabled = 0;
+        vgic_its_free_device_list(kvm, its);
+        vgic_its_free_collection_list(kvm, its);
+}
+
 static int vgic_its_has_attr(struct kvm_device *dev,
                              struct kvm_device_attr *attr)
 {
@@ -2360,6 +2341,8 @@ static int vgic_its_has_attr(struct kvm_device *dev,
                 switch (attr->attr) {
                 case KVM_DEV_ARM_VGIC_CTRL_INIT:
                         return 0;
+                case KVM_DEV_ARM_ITS_CTRL_RESET:
+                        return 0;
                 case KVM_DEV_ARM_ITS_SAVE_TABLES:
                         return 0;
                 case KVM_DEV_ARM_ITS_RESTORE_TABLES:
@@ -2372,6 +2355,41 @@ static int vgic_its_has_attr(struct kvm_device *dev,
         return -ENXIO;
 }
 
+static int vgic_its_ctrl(struct kvm *kvm, struct vgic_its *its, u64 attr)
+{
+        const struct vgic_its_abi *abi = vgic_its_get_abi(its);
+        int ret = 0;
+
+        if (attr == KVM_DEV_ARM_VGIC_CTRL_INIT) /* Nothing to do */
+                return 0;
+
+        mutex_lock(&kvm->lock);
+        mutex_lock(&its->its_lock);
+
+        if (!lock_all_vcpus(kvm)) {
+                mutex_unlock(&its->its_lock);
+                mutex_unlock(&kvm->lock);
+                return -EBUSY;
+        }
+
+        switch (attr) {
+        case KVM_DEV_ARM_ITS_CTRL_RESET:
+                vgic_its_reset(kvm, its);
+                break;
+        case KVM_DEV_ARM_ITS_SAVE_TABLES:
+                ret = abi->save_tables(its);
+                break;
+        case KVM_DEV_ARM_ITS_RESTORE_TABLES:
+                ret = abi->restore_tables(its);
+                break;
+        }
+
+        unlock_all_vcpus(kvm);
+        mutex_unlock(&its->its_lock);
+        mutex_unlock(&kvm->lock);
+        return ret;
+}
+
 static int vgic_its_set_attr(struct kvm_device *dev,
                              struct kvm_device_attr *attr)
 {
@@ -2397,19 +2415,8 @@ static int vgic_its_set_attr(struct kvm_device *dev,
 
                 return vgic_register_its_iodev(dev->kvm, its, addr);
         }
-        case KVM_DEV_ARM_VGIC_GRP_CTRL: {
-                const struct vgic_its_abi *abi = vgic_its_get_abi(its);
-
-                switch (attr->attr) {
-                case KVM_DEV_ARM_VGIC_CTRL_INIT:
-                        /* Nothing to do */
-                        return 0;
-                case KVM_DEV_ARM_ITS_SAVE_TABLES:
-                        return abi->save_tables(its);
-                case KVM_DEV_ARM_ITS_RESTORE_TABLES:
-                        return abi->restore_tables(its);
-                }
-        }
+        case KVM_DEV_ARM_VGIC_GRP_CTRL:
+                return vgic_its_ctrl(dev->kvm, its, attr->attr);
         case KVM_DEV_ARM_VGIC_GRP_ITS_REGS: {
                 u64 __user *uaddr = (u64 __user *)(long)attr->addr;
                 u64 reg;