Add framework for VM functions to handle stage-2 write faults from Gunyah
guest virtual machines. IO handlers have a range of addresses which they
apply to. Optionally, they may apply to only when the value written
matches the IO handler's value.
Reviewed-by: Alex Elder <elder@xxxxxxxxxx>
Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@xxxxxxxxxxx>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@xxxxxxxxxxx>
Signed-off-by: Elliot Berman <quic_eberman@xxxxxxxxxxx>
---
drivers/virt/gunyah/gunyah_vcpu.c | 4 ++
drivers/virt/gunyah/vm_mgr.c | 115 ++++++++++++++++++++++++++++++++++++++
drivers/virt/gunyah/vm_mgr.h | 8 +++
include/linux/gunyah.h | 29 ++++++++++
4 files changed, 156 insertions(+)
diff --git a/drivers/virt/gunyah/gunyah_vcpu.c b/drivers/virt/gunyah/gunyah_vcpu.c
index f8306620b1dd6..ef78503fe586d 100644
--- a/drivers/virt/gunyah/gunyah_vcpu.c
+++ b/drivers/virt/gunyah/gunyah_vcpu.c
@@ -133,6 +133,10 @@ gunyah_handle_mmio(struct gunyah_vcpu *vcpu, unsigned long resume_data[3],
vcpu->state = GUNYAH_VCPU_RUN_STATE_MMIO_READ;
vcpu->mmio_read_len = len;
} else { /* GUNYAH_VCPU_ADDRSPACE_VMMIO_WRITE */
+ if (!gunyah_vm_mmio_write(vcpu->ghvm, addr, len, data)) {
+ resume_data[0] = GUNYAH_ADDRSPACE_VMMIO_ACTION_EMULATE;
+ return true;
+ }
vcpu->vcpu_run->mmio.is_write = 1;
memcpy(vcpu->vcpu_run->mmio.data, &data, len);
vcpu->state = GUNYAH_VCPU_RUN_STATE_MMIO_WRITE;
diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
index a61a3f3ae92f1..2434be5dffe08 100644
--- a/drivers/virt/gunyah/vm_mgr.c
+++ b/drivers/virt/gunyah/vm_mgr.c
@@ -302,6 +302,118 @@ static void gunyah_vm_clean_resources(struct gunyah_vm *ghvm)
mutex_unlock(&ghvm->resources_lock);
}
+static int _gunyah_vm_io_handler_compare(const struct rb_node *node,
+ const struct rb_node *parent)
+{
+ struct gunyah_vm_io_handler *n =
+ container_of(node, struct gunyah_vm_io_handler, node);
+ struct gunyah_vm_io_handler *p =
+ container_of(parent, struct gunyah_vm_io_handler, node);
+
+ if (n->addr < p->addr)
+ return -1;
+ if (n->addr > p->addr)
+ return 1;
+ if ((n->len && !p->len) || (!n->len && p->len))
+ return 0;
+ if (n->len < p->len)
+ return -1;
+ if (n->len > p->len)
+ return 1;
+ /* one of the io handlers doesn't have datamatch and the other does.
+ * For purposes of comparison, that makes them identical since the
+ * one that doesn't have datamatch will cover the same handler that
+ * does.
+ */
+ if (n->datamatch != p->datamatch)
+ return 0;
+ if (n->data < p->data)
+ return -1;
+ if (n->data > p->data)
+ return 1;
+ return 0;
+}
+
+static int gunyah_vm_io_handler_compare(struct rb_node *node,
+ const struct rb_node *parent)
+{
+ return _gunyah_vm_io_handler_compare(node, parent);
+}
+
+static int gunyah_vm_io_handler_find(const void *key,
+ const struct rb_node *node)
+{
+ const struct gunyah_vm_io_handler *k = key;
+
+ return _gunyah_vm_io_handler_compare(&k->node, node);
+}
+
+static struct gunyah_vm_io_handler *
+gunyah_vm_mgr_find_io_hdlr(struct gunyah_vm *ghvm, u64 addr, u64 len, u64 data)
+{
+ struct gunyah_vm_io_handler key = {
+ .addr = addr,
+ .len = len,
+ .datamatch = true,
+ .data = data,
+ };
+ struct rb_node *node;
+
+ node = rb_find(&key, &ghvm->mmio_handler_root,
+ gunyah_vm_io_handler_find);
+ if (!node)
+ return NULL;
+
+ return container_of(node, struct gunyah_vm_io_handler, node);
+}
+
+int gunyah_vm_mmio_write(struct gunyah_vm *ghvm, u64 addr, u32 len, u64 data)
+{
+ struct gunyah_vm_io_handler *io_hdlr = NULL;
+ int ret;
+
+ down_read(&ghvm->mmio_handler_lock);
+ io_hdlr = gunyah_vm_mgr_find_io_hdlr(ghvm, addr, len, data);
+ if (!io_hdlr || !io_hdlr->ops || !io_hdlr->ops->write) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ ret = io_hdlr->ops->write(io_hdlr, addr, len, data);
+
+out:
+ up_read(&ghvm->mmio_handler_lock);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(gunyah_vm_mmio_write);
+
+int gunyah_vm_add_io_handler(struct gunyah_vm *ghvm,
+ struct gunyah_vm_io_handler *io_hdlr)
+{
+ struct rb_node *found;
+
+ if (io_hdlr->datamatch &&
+ (!io_hdlr->len || io_hdlr->len > sizeof(io_hdlr->data)))
+ return -EINVAL;
+
+ down_write(&ghvm->mmio_handler_lock);
+ found = rb_find_add(&io_hdlr->node, &ghvm->mmio_handler_root,
+ gunyah_vm_io_handler_compare);
+ up_write(&ghvm->mmio_handler_lock);
+
+ return found ? -EEXIST : 0;
+}
+EXPORT_SYMBOL_GPL(gunyah_vm_add_io_handler);
+
+void gunyah_vm_remove_io_handler(struct gunyah_vm *ghvm,
+ struct gunyah_vm_io_handler *io_hdlr)
+{
+ down_write(&ghvm->mmio_handler_lock);
+ rb_erase(&io_hdlr->node, &ghvm->mmio_handler_root);
+ up_write(&ghvm->mmio_handler_lock);
+}
+EXPORT_SYMBOL_GPL(gunyah_vm_remove_io_handler);
+
static int gunyah_vm_rm_notification_status(struct gunyah_vm *ghvm, void *data)
{
struct gunyah_rm_vm_status_payload *payload = data;
@@ -404,6 +516,9 @@ static __must_check struct gunyah_vm *gunyah_vm_alloc(struct gunyah_rm *rm)
INIT_LIST_HEAD(&ghvm->resource_tickets);
xa_init(&ghvm->boot_context);
+ init_rwsem(&ghvm->mmio_handler_lock);
+ ghvm->mmio_handler_root = RB_ROOT;
+
mt_init(&ghvm->mm);
mt_init(&ghvm->bindings);
init_rwsem(&ghvm->bindings_lock);
diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
index 8cee93e551700..daddb1d0cb70b 100644
--- a/drivers/virt/gunyah/vm_mgr.h
+++ b/drivers/virt/gunyah/vm_mgr.h
@@ -11,6 +11,7 @@
#include <linux/maple_tree.h>
#include <linux/mutex.h>
#include <linux/pagemap.h>
+#include <linux/rbtree.h>
#include <linux/rwsem.h>
#include <linux/set_memory.h>
#include <linux/wait.h>
@@ -58,6 +59,9 @@ long gunyah_dev_vm_mgr_ioctl(struct gunyah_rm *rm, unsigned int cmd,
* @guest_shared_extent_ticket: Resource ticket to the capability for
* the memory extent that represents
* memory shared with the guest.
+ * @mmio_handler_root: RB tree of MMIO handlers.
+ * Entries are &struct gunyah_vm_io_handler
+ * @mmio_handler_lock: Serialization of traversing @mmio_handler_root
* @rm: Pointer to the resource manager struct to make RM calls
* @parent: For logging
* @nb: Notifier block for RM notifications
@@ -93,6 +97,8 @@ struct gunyah_vm {
struct gunyah_vm_resource_ticket addrspace_ticket,
host_private_extent_ticket, host_shared_extent_ticket,
guest_private_extent_ticket, guest_shared_extent_ticket;
+ struct rb_root mmio_handler_root;
+ struct rw_semaphore mmio_handler_lock;
struct gunyah_rm *rm;
@@ -119,6 +125,8 @@ struct gunyah_vm {
struct xarray boot_context;
};
+int gunyah_vm_mmio_write(struct gunyah_vm *ghvm, u64 addr, u32 len, u64 data);
+
/**
* folio_mmapped() - Returns true if the folio is mapped into any vma
* @folio: Folio to test
diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
index a9d58150de696..dbd5b0251b491 100644
--- a/include/linux/gunyah.h
+++ b/include/linux/gunyah.h
@@ -155,6 +155,35 @@ int gunyah_vm_add_resource_ticket(struct gunyah_vm *ghvm,
void gunyah_vm_remove_resource_ticket(struct gunyah_vm *ghvm,
struct gunyah_vm_resource_ticket *ticket);
+/*
+ * gunyah_vm_io_handler contains the info about an io device and its associated
+ * addr and the ops associated with the io device.
+ */
+struct gunyah_vm_io_handler {
+ struct rb_node node;
+ u64 addr;
+
+ bool datamatch;
+ u8 len;
+ u64 data;
+ struct gunyah_vm_io_handler_ops *ops;
+};
+
+/*
+ * gunyah_vm_io_handler_ops contains function pointers associated with an iodevice.
+ */
+struct gunyah_vm_io_handler_ops {
+ int (*read)(struct gunyah_vm_io_handler *io_dev, u64 addr, u32 len,
+ u64 data);
+ int (*write)(struct gunyah_vm_io_handler *io_dev, u64 addr, u32 len,
+ u64 data);
+};
+
+int gunyah_vm_add_io_handler(struct gunyah_vm *ghvm,
+ struct gunyah_vm_io_handler *io_dev);
+void gunyah_vm_remove_io_handler(struct gunyah_vm *ghvm,
+ struct gunyah_vm_io_handler *io_dev);
+
#define GUNYAH_RM_ACL_X BIT(0)
#define GUNYAH_RM_ACL_W BIT(1)
#define GUNYAH_RM_ACL_R BIT(2)
--
2.34.1
