[PATCH v5 06/13] virt: gunyah: Identify hypervisor version

[Elliot Berman <quic_eberman@xxxxxxxxxxx>]

Export the version of Gunyah which is reported via the hyp_identify
hypercall. Increments of the major API version indicate possibly
backwards incompatible changes. Export the hypervisor identity so that
Gunyah drivers can act according to the major API version.

Signed-off-by: Elliot Berman <quic_eberman@xxxxxxxxxxx>
---
 MAINTAINERS                  |  1 +
 drivers/virt/Makefile        |  1 +
 drivers/virt/gunyah/Makefile |  2 ++
 drivers/virt/gunyah/gunyah.c | 41 ++++++++++++++++++++++++++++++++++++
 include/asm-generic/gunyah.h |  3 +++
 5 files changed, 48 insertions(+)
 create mode 100644 drivers/virt/gunyah/Makefile
 create mode 100644 drivers/virt/gunyah/gunyah.c

diff --git a/MAINTAINERS b/MAINTAINERS
index ed2bc98c3818..c5458aeec023 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8884,6 +8884,7 @@ M:	Elliot Berman <quic_eberman@xxxxxxxxxxx>
 M:	Murali Nalajala <quic_mnalajal@xxxxxxxxxxx>
 L:	linux-arm-msm@xxxxxxxxxxxxxxx
 S:	Supported
+F:	Documentation/ABI/testing/sysfs-hypervisor-gunyah
 F:	Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
 F:	Documentation/virt/gunyah/
 F:	arch/arm64/gunyah/
diff --git a/drivers/virt/Makefile b/drivers/virt/Makefile
index 093674e05c40..10b87f934730 100644
--- a/drivers/virt/Makefile
+++ b/drivers/virt/Makefile
@@ -11,3 +11,4 @@ obj-$(CONFIG_NITRO_ENCLAVES)	+= nitro_enclaves/
 obj-$(CONFIG_ACRN_HSM)		+= acrn/
 obj-$(CONFIG_EFI_SECRET)	+= coco/efi_secret/
 obj-$(CONFIG_SEV_GUEST)		+= coco/sev-guest/
+obj-$(CONFIG_GUNYAH)		+= gunyah/
diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
new file mode 100644
index 000000000000..dc081e2dc02b
--- /dev/null
+++ b/drivers/virt/gunyah/Makefile
@@ -0,0 +1,2 @@
+gunyah-y += gunyah.o
+obj-$(CONFIG_GUNYAH) += gunyah.o
diff --git a/drivers/virt/gunyah/gunyah.c b/drivers/virt/gunyah/gunyah.c
new file mode 100644
index 000000000000..2893a56f3dfc
--- /dev/null
+++ b/drivers/virt/gunyah/gunyah.c
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#define pr_fmt(fmt) "gunyah: " fmt
+
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/init.h>
+#include <asm-generic/gunyah.h>
+
+struct gh_hypercall_hyp_identify_resp gunyah_api;
+EXPORT_SYMBOL(gunyah_api);
+
+static int __init gunyah_init(void)
+{
+	u32 uid[4];
+
+	gh_hypercall_get_uid(uid);
+
+	if (!(gh_uid_matches(GUNYAH, uid) || gh_uid_matches(QC_HYP, uid)))
+		return 0;
+
+	gh_hypercall_hyp_identify(&gunyah_api);
+
+	pr_info("Running under Gunyah hypervisor %llx/v%lld\n",
+		  GH_API_INFO_VARIANT(gunyah_api.api_info),
+		  GH_API_INFO_API_VERSION(gunyah_api.api_info));
+
+	return 0;
+}
+arch_initcall(gunyah_init);
+
+static void __exit gunyah_exit(void)
+{
+}
+module_exit(gunyah_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Gunyah Hypervisor Driver");
diff --git a/include/asm-generic/gunyah.h b/include/asm-generic/gunyah.h
index 86eb59e203ef..8f9d4c649ba8 100644
--- a/include/asm-generic/gunyah.h
+++ b/include/asm-generic/gunyah.h
@@ -85,6 +85,8 @@ static inline int gh_remap_error(int gh_error)
 	((uid)[0] == prefix ## _UID0 && (uid)[1] == prefix ## _UID1 && \
 	 (uid)[2] == prefix ## _UID2 && (uid)[3] == prefix ## _UID3)
 
+#define GUNYAH_API_V1			1
+
 #define GH_API_INFO_API_VERSION(x)	(((x) >> 0) & 0x3fff)
 #define GH_API_INFO_BIG_ENDIAN(x)	(((x) >> 14) & 1)
 #define GH_API_INFO_IS_64BIT(x)		(((x) >> 15) & 1)
@@ -103,6 +105,7 @@ struct gh_hypercall_hyp_identify_resp {
 	u64 api_info;
 	u64 flags[3];
 };
+extern struct gh_hypercall_hyp_identify_resp gunyah_api;
 
 void gh_hypercall_get_uid(u32 *uid);
 void gh_hypercall_hyp_identify(struct gh_hypercall_hyp_identify_resp *hyp_identity);
-- 
2.25.1