On 5/9/23 3:47 PM, Elliot Berman wrote:
Add hypercalls to identify when Linux is running a virtual machine under
Gunyah.
There are two calls to help identify Gunyah:
1. gh_hypercall_get_uid() returns a UID when running under a Gunyah
hypervisor.
2. gh_hypercall_hyp_identify() returns build information and a set of
feature flags that are supported by Gunyah.
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
Signed-off-by: Elliot Berman <quic_eberman@xxxxxxxxxxx>
I have a suggestion below. But whether or not you choose to
incorporate it:
Reviewed-by: Alex Elder <elder@xxxxxxxxxx>
---
arch/arm64/Kbuild | 1 +
arch/arm64/gunyah/Makefile | 3 ++
arch/arm64/gunyah/gunyah_hypercall.c | 56 ++++++++++++++++++++++++++++
drivers/virt/Kconfig | 2 +
drivers/virt/gunyah/Kconfig | 13 +++++++
include/linux/gunyah.h | 31 +++++++++++++++
6 files changed, 106 insertions(+)
create mode 100644 arch/arm64/gunyah/Makefile
create mode 100644 arch/arm64/gunyah/gunyah_hypercall.c
create mode 100644 drivers/virt/gunyah/Kconfig
diff --git a/arch/arm64/Kbuild b/arch/arm64/Kbuild
index 5bfbf7d79c99..e4847ba0e3c9 100644
--- a/arch/arm64/Kbuild
+++ b/arch/arm64/Kbuild
@@ -3,6 +3,7 @@ obj-y += kernel/ mm/ net/
obj-$(CONFIG_KVM) += kvm/
obj-$(CONFIG_XEN) += xen/
obj-$(subst m,y,$(CONFIG_HYPERV)) += hyperv/
+obj-$(CONFIG_GUNYAH) += gunyah/
obj-$(CONFIG_CRYPTO) += crypto/
# for cleaning
diff --git a/arch/arm64/gunyah/Makefile b/arch/arm64/gunyah/Makefile
new file mode 100644
index 000000000000..84f1e38cafb1
--- /dev/null
+++ b/arch/arm64/gunyah/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_GUNYAH) += gunyah_hypercall.o
diff --git a/arch/arm64/gunyah/gunyah_hypercall.c b/arch/arm64/gunyah/gunyah_hypercall.c
new file mode 100644
index 000000000000..2166d5dab869
--- /dev/null
+++ b/arch/arm64/gunyah/gunyah_hypercall.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/module.h>
+#include <linux/gunyah.h>
+#include <linux/uuid.h>
+
+/* {c1d58fcd-a453-5fdb-9265-ce36673d5f14} */
+static const uuid_t GUNYAH_UUID =
+ UUID_INIT(0xc1d58fcd, 0xa453, 0x5fdb, 0x92, 0x65, 0xce, 0x36, 0x67, 0x3d, 0x5f, 0x14);
+
+bool arch_is_gh_guest(void)
+{
+ struct arm_smccc_res res;
+ uuid_t uuid;
+
+ arm_smccc_1_1_hvc(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res);
+
+ ((u32 *)&uuid.b[0])[0] = lower_32_bits(res.a0);
+ ((u32 *)&uuid.b[0])[1] = lower_32_bits(res.a1);
+ ((u32 *)&uuid.b[0])[2] = lower_32_bits(res.a2);
+ ((u32 *)&uuid.b[0])[3] = lower_32_bits(res.a3);
I think I'd rather see this more like:
u32 *up = (u32 *)&uuid.b;
/* The lower bytes of the four result fields encode the UUID */
*up++ = lower_32_bits(res.a0);
*up++ = lower_32_bits(res.a1);
*up++ = lower_32_bits(res.a2);
*up = lower_32_bits(res.a3);
Basically I think casting the assigned-to value makes things
harder to read. So doing that cast just once seems simpler.
But it's not a big deal.
+
+ return uuid_equal(&uuid, &GUNYAH_UUID);
+}
+EXPORT_SYMBOL_GPL(arch_is_gh_guest);
. . .
