On 5/9/23 3:47 PM, Elliot Berman wrote:
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.
You might be able to avoid the lock by using rcu_assign_pointer() and
rcu_dereference(), but I'm not recommending it (because I'm not sure).
I have one more suggestion below.
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/Kconfig | 4 ++
drivers/virt/gunyah/Makefile | 2 +
drivers/virt/gunyah/gunyah_platform_hooks.c | 80 +++++++++++++++++++++
drivers/virt/gunyah/rsc_mgr.h | 3 +
drivers/virt/gunyah/rsc_mgr_rpc.c | 18 ++++-
include/linux/gunyah_rsc_mgr.h | 17 +++++
6 files changed, 122 insertions(+), 2 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 bacf78b8fa33..4fbeee521d60 100644
--- a/drivers/virt/gunyah/Makefile
+++ b/drivers/virt/gunyah/Makefile
@@ -1,4 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_GUNYAH_PLATFORM_HOOKS) += gunyah_platform_hooks.o
+
gunyah-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o vm_mgr_mm.o
obj-$(CONFIG_GUNYAH) += gunyah.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..60da0e154e98
--- /dev/null
+++ b/drivers/virt/gunyah/gunyah_platform_hooks.c
@@ -0,0 +1,80 @@
+// 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 gh_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 gh_rm_platform_ops *platform_ops)
Can (should) platform_ops be declared as const? (I think it can,
that would be better as long as you don't expect operation function
pointers to be added after registration.) If you do that, all such
arguments will probably need to be updated to pointer-to-const.
+{
+ 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);
. . .
