[PATCH v7 06/20] 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>
---
 drivers/virt/Makefile        |  1 +
 drivers/virt/gunyah/Makefile |  1 +
 drivers/virt/gunyah/gunyah.c | 46 ++++++++++++++++++++++++++++++++++++
 include/linux/gunyah.h       |  6 +++++
 4 files changed, 54 insertions(+)
 create mode 100644 drivers/virt/gunyah/Makefile
 create mode 100644 drivers/virt/gunyah/gunyah.c

diff --git a/drivers/virt/Makefile b/drivers/virt/Makefile
index 093674e05c40..92b7e5311548 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-y				+= gunyah/
diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
new file mode 100644
index 000000000000..2ac4ee64b89d
--- /dev/null
+++ b/drivers/virt/gunyah/Makefile
@@ -0,0 +1 @@
+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..c34c9046fc08
--- /dev/null
+++ b/drivers/virt/gunyah/gunyah.c
@@ -0,0 +1,46 @@
+// 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/gunyah.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+
+struct gh_hypercall_hyp_identify_resp gunyah_api;
+EXPORT_SYMBOL_GPL(gunyah_api);
+
+static const uint32_t gunyah_known_uuids[][4] = {
+	{0x19bd54bd, 0x0b37571b, 0x946f609b, 0x54539de6}, /* QC_HYP (Qualcomm's build) */
+	{0x673d5f14, 0x9265ce36, 0xa4535fdb, 0xc1d58fcd}, /* GUNYAH (open source build) */
+};
+
+static int __init gunyah_init(void)
+{
+	u32 uid[4];
+	int i;
+
+	gh_hypercall_get_uid(uid);
+
+	for (i = 0; i < ARRAY_SIZE(gunyah_known_uuids); i++)
+		if (!memcmp(uid, gunyah_known_uuids[i], sizeof(uid)))
+			break;
+
+	if (i == ARRAY_SIZE(gunyah_known_uuids))
+		return -ENODEV;
+
+	gh_hypercall_hyp_identify(&gunyah_api);
+
+	pr_info("Running under Gunyah hypervisor %llx/v%u\n",
+		FIELD_GET(GH_API_INFO_VARIANT_MASK, gunyah_api.api_info),
+		gh_api_version());
+
+	return 0;
+}
+arch_initcall(gunyah_init);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Gunyah Hypervisor Driver");
diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
index 2765d2b40198..166156f69df9 100644
--- a/include/linux/gunyah.h
+++ b/include/linux/gunyah.h
@@ -92,6 +92,12 @@ struct gh_hypercall_hyp_identify_resp {
 	u64 api_info;
 	u64 flags[3];
 };
+extern struct gh_hypercall_hyp_identify_resp gunyah_api;
+
+static inline u16 gh_api_version(void)
+{
+	return FIELD_GET(GH_API_INFO_API_VERSION_MASK, gunyah_api.api_info);
+}
 
 void gh_hypercall_get_uid(u32 uid[4]);
 void gh_hypercall_hyp_identify(struct gh_hypercall_hyp_identify_resp *hyp_identity);
-- 
2.25.1