[PATCH v9 16/27] gunyah: rsc_mgr: Add platform ops on mem_lend/mem_reclaim

[Elliot Berman]

On Qualcomm platforms, there is a firmware entity which controls access
to physical pages. In order to share memory with another VM, this entity
needs to be informed that the guest VM should have access to the memory.

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/Kconfig                 |  4 ++
 drivers/virt/gunyah/Makefile                |  1 +
 drivers/virt/gunyah/gunyah_platform_hooks.c | 63 +++++++++++++++++++++
 drivers/virt/gunyah/rsc_mgr.h               |  3 +
 drivers/virt/gunyah/rsc_mgr_rpc.c           |  9 ++-
 include/linux/gunyah_rsc_mgr.h              | 14 +++++
 6 files changed, 91 insertions(+), 3 deletions(-)
 create mode 100644 drivers/virt/gunyah/gunyah_platform_hooks.c

diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig
index 1a737694c333..de815189dab6 100644
--- a/drivers/virt/gunyah/Kconfig
+++ b/drivers/virt/gunyah/Kconfig
@@ -4,6 +4,7 @@ config GUNYAH
 	tristate "Gunyah Virtualization drivers"
 	depends on ARM64
 	depends on MAILBOX
+	select GUNYAH_PLATFORM_HOOKS
 	help
 	  The Gunyah drivers are the helper interfaces that run in a guest VM
 	  such as basic inter-VM IPC and signaling mechanisms, and higher level
@@ -11,3 +12,6 @@ config GUNYAH
 
 	  Say Y/M here to enable the drivers needed to interact in a Gunyah
 	  virtual environment.
+
+config GUNYAH_PLATFORM_HOOKS
+	tristate
diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
index ff8bc4925392..6b8f84dbfe0d 100644
--- a/drivers/virt/gunyah/Makefile
+++ b/drivers/virt/gunyah/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_GUNYAH) += gunyah.o
+obj-$(CONFIG_GUNYAH_PLATFORM_HOOKS) += gunyah_platform_hooks.o
 
 gunyah_rsc_mgr-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o vm_mgr_mm.o
 obj-$(CONFIG_GUNYAH) += gunyah_rsc_mgr.o
diff --git a/drivers/virt/gunyah/gunyah_platform_hooks.c b/drivers/virt/gunyah/gunyah_platform_hooks.c
new file mode 100644
index 000000000000..73ea229438ca
--- /dev/null
+++ b/drivers/virt/gunyah/gunyah_platform_hooks.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/module.h>
+#include <linux/rwsem.h>
+#include <linux/gunyah_rsc_mgr.h>
+
+#include "rsc_mgr.h"
+
+static struct gunyah_rm_platform_ops *rm_platform_ops;
+static DECLARE_RWSEM(rm_platform_ops_lock);
+
+int gh_rm_platform_pre_mem_share(struct gh_rm *rm, struct gh_rm_mem_parcel *mem_parcel)
+{
+	int ret = 0;
+
+	down_read(&rm_platform_ops_lock);
+	if (rm_platform_ops && rm_platform_ops->pre_mem_share)
+		ret = rm_platform_ops->pre_mem_share(rm, mem_parcel);
+	up_read(&rm_platform_ops_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gh_rm_platform_pre_mem_share);
+
+int gh_rm_platform_post_mem_reclaim(struct gh_rm *rm, struct gh_rm_mem_parcel *mem_parcel)
+{
+	int ret = 0;
+
+	down_read(&rm_platform_ops_lock);
+	if (rm_platform_ops && rm_platform_ops->post_mem_reclaim)
+		ret = rm_platform_ops->post_mem_reclaim(rm, mem_parcel);
+	up_read(&rm_platform_ops_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gh_rm_platform_post_mem_reclaim);
+
+int gh_rm_register_platform_ops(struct gunyah_rm_platform_ops *platform_ops)
+{
+	int ret = 0;
+
+	down_write(&rm_platform_ops_lock);
+	if (!rm_platform_ops)
+		rm_platform_ops = platform_ops;
+	else
+		ret = -EEXIST;
+	up_write(&rm_platform_ops_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gh_rm_register_platform_ops);
+
+void gh_rm_unregister_platform_ops(struct gunyah_rm_platform_ops *platform_ops)
+{
+	down_write(&rm_platform_ops_lock);
+	if (rm_platform_ops == platform_ops)
+		rm_platform_ops = NULL;
+	up_write(&rm_platform_ops_lock);
+}
+EXPORT_SYMBOL_GPL(gh_rm_unregister_platform_ops);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Gunyah Platform Hooks");
diff --git a/drivers/virt/gunyah/rsc_mgr.h b/drivers/virt/gunyah/rsc_mgr.h
index 17047afefb28..8486f6b7bd50 100644
--- a/drivers/virt/gunyah/rsc_mgr.h
+++ b/drivers/virt/gunyah/rsc_mgr.h
@@ -68,6 +68,9 @@ struct gh_rm;
 int gh_rm_call(struct gh_rm *rsc_mgr, u32 message_id, void *req_buff, size_t req_buff_size,
 		void **resp_buf, size_t *resp_buff_size);
 
+int gh_rm_platform_pre_mem_share(struct gh_rm *rm, struct gh_rm_mem_parcel *mem_parcel);
+int gh_rm_platform_post_mem_reclaim(struct gh_rm *rm, struct gh_rm_mem_parcel *mem_parcel);
+
 /* Message IDs: Memory Management */
 #define GH_RM_RPC_MEM_LEND			0x51000012
 #define GH_RM_RPC_MEM_SHARE			0x51000013
diff --git a/drivers/virt/gunyah/rsc_mgr_rpc.c b/drivers/virt/gunyah/rsc_mgr_rpc.c
index a3633df98a38..ea4b8be1504b 100644
--- a/drivers/virt/gunyah/rsc_mgr_rpc.c
+++ b/drivers/virt/gunyah/rsc_mgr_rpc.c
@@ -168,8 +168,11 @@ static int gh_rm_mem_lend_common(struct gh_rm *rm, u32 message_id, struct gh_rm_
 		goto out;
 	}
 
-	if (resp_size != sizeof(__le32)) {
-		ret = -EIO;
+	if (resp_size != sizeof(*resp)) {
+		pr_warn("%s: unexpected payload size: %ld Expected: %ld", __func__,
+			resp_size, sizeof(*resp));
+		ret = -EBADMSG;
+		gh_rm_platform_post_mem_reclaim(rm, p);
 		goto out;
 	}
 
@@ -243,7 +246,7 @@ int gh_rm_mem_reclaim(struct gh_rm *rm, struct gh_rm_mem_parcel *parcel)
 		return -EBADMSG;
 	}
 
-	return ret;
+	return gh_rm_platform_post_mem_reclaim(rm, parcel);
 }
 EXPORT_SYMBOL_GPL(gh_rm_mem_reclaim);
 
diff --git a/include/linux/gunyah_rsc_mgr.h b/include/linux/gunyah_rsc_mgr.h
index 264f054540b8..dd94bb3f378b 100644
--- a/include/linux/gunyah_rsc_mgr.h
+++ b/include/linux/gunyah_rsc_mgr.h
@@ -120,4 +120,18 @@ int gh_rm_get_hyp_resources(struct gh_rm *rm, u16 vmid,
 				struct gh_rm_hyp_resources **resources);
 int gh_rm_get_vmid(struct gh_rm *rm, u16 *vmid);
 
+struct gunyah_rm_platform_ops {
+	int (*pre_mem_share)(struct gh_rm *rm, struct gh_rm_mem_parcel *mem_parcel);
+	int (*post_mem_reclaim)(struct gh_rm *rm, struct gh_rm_mem_parcel *mem_parcel);
+};
+
+#if IS_ENABLED(CONFIG_GUNYAH_PLATFORM_HOOKS)
+int gh_rm_register_platform_ops(struct gunyah_rm_platform_ops *platform_ops);
+void gh_rm_unregister_platform_ops(struct gunyah_rm_platform_ops *platform_ops);
+#else
+static inline int gh_rm_register_platform_ops(struct gunyah_rm_platform_ops *platform_ops)
+	{ return 0; }
+static inline void gh_rm_unregister_platform_ops(struct gunyah_rm_platform_ops *platform_ops) { }
+#endif
+
 #endif
-- 
2.39.0