diff mbox series

[v10,04/26] virt: gunyah: Add hypercalls to identify Gunyah

Message ID 20230214211229.3239350-5-quic_eberman@quicinc.com (mailing list archive)
State Not Applicable
Headers show
Series None | expand

Commit Message

Elliot Berman Feb. 14, 2023, 9:12 p.m. UTC 
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.

Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 arch/arm64/Kbuild                    |  1 +
 arch/arm64/gunyah/Makefile           |  3 ++
 arch/arm64/gunyah/gunyah_hypercall.c | 61 ++++++++++++++++++++++++++++
 drivers/virt/Kconfig                 |  2 +
 drivers/virt/gunyah/Kconfig          | 13 ++++++
 include/linux/gunyah.h               | 33 +++++++++++++++
 6 files changed, 113 insertions(+)
 create mode 100644 arch/arm64/gunyah/Makefile
 create mode 100644 arch/arm64/gunyah/gunyah_hypercall.c
 create mode 100644 drivers/virt/gunyah/Kconfig

Comments

Srinivas Kandagatla Feb. 20, 2023, 1:59 p.m. UTC | #1 
minor nits below,

On 14/02/2023 21:12, 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.
> 
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
>   arch/arm64/Kbuild                    |  1 +
>   arch/arm64/gunyah/Makefile           |  3 ++
>   arch/arm64/gunyah/gunyah_hypercall.c | 61 ++++++++++++++++++++++++++++
>   drivers/virt/Kconfig                 |  2 +
>   drivers/virt/gunyah/Kconfig          | 13 ++++++
>   include/linux/gunyah.h               | 33 +++++++++++++++
>   6 files changed, 113 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..f30d06ee80cf
> --- /dev/null
> +++ b/arch/arm64/gunyah/gunyah_hypercall.c
> @@ -0,0 +1,61 @@
> +// 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>
> +
> +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) */
> +};
> +
> +bool arch_is_gunyah_guest(void)
> +{
> +	struct arm_smccc_res res;
> +	u32 uid[4];
> +	int i;
> +
> +	arm_smccc_1_1_hvc(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res);
> +
> +	uid[0] = lower_32_bits(res.a0);
> +	uid[1] = lower_32_bits(res.a1);
> +	uid[2] = lower_32_bits(res.a2);
> +	uid[3] = lower_32_bits(res.a3);
> +
> +	for (i = 0; i < ARRAY_SIZE(gunyah_known_uuids); i++)
> +		if (!memcmp(uid, gunyah_known_uuids[i], sizeof(uid)))
> +			break;
> +
> +	return i != ARRAY_SIZE(gunyah_known_uuids);

you could probably make this more readable by:


for (i = 0; i < ARRAY_SIZE(gunyah_known_uuids); i++)
	if (!memcmp(uid, gunyah_known_uuids[i], sizeof(uid)))
		return true;

return false;

> +}
> +EXPORT_SYMBOL_GPL(arch_is_gunyah_guest);
> +
> +#define GH_HYPERCALL(fn)	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_64, \
> +						   ARM_SMCCC_OWNER_VENDOR_HYP, \
> +						   fn)
> +
> +#define GH_HYPERCALL_HYP_IDENTIFY		GH_HYPERCALL(0x8000)
> +
> +/**
> + * gh_hypercall_hyp_identify() - Returns build information and feature flags
> + *                               supported by Gunyah.
> + * @hyp_identity: filled by the hypercall with the API info and feature flags.
> + */
> +void gh_hypercall_hyp_identify(struct gh_hypercall_hyp_identify_resp *hyp_identity)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_hvc(GH_HYPERCALL_HYP_IDENTIFY, &res);
> +
> +	hyp_identity->api_info = res.a0;
> +	hyp_identity->flags[0] = res.a1;
> +	hyp_identity->flags[1] = res.a2;
> +	hyp_identity->flags[2] = res.a3;
> +}
> +EXPORT_SYMBOL_GPL(gh_hypercall_hyp_identify);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Gunyah Hypervisor Hypercalls");
> diff --git a/drivers/virt/Kconfig b/drivers/virt/Kconfig
> index f79ab13a5c28..85bd6626ffc9 100644
> --- a/drivers/virt/Kconfig
> +++ b/drivers/virt/Kconfig
> @@ -54,4 +54,6 @@ source "drivers/virt/coco/sev-guest/Kconfig"
>   
>   source "drivers/virt/coco/tdx-guest/Kconfig"
>   
> +source "drivers/virt/gunyah/Kconfig"
> +
>   endif
> diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig
> new file mode 100644
> index 000000000000..1a737694c333
> --- /dev/null
> +++ b/drivers/virt/gunyah/Kconfig
> @@ -0,0 +1,13 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +
> +config GUNYAH
> +	tristate "Gunyah Virtualization drivers"
> +	depends on ARM64
> +	depends on MAILBOX
> +	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
> +	  services such as memory/device sharing, IRQ sharing, and so on.
> +
> +	  Say Y/M here to enable the drivers needed to interact in a Gunyah
> +	  virtual environment.
> diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
> index 59ef4c735ae8..3fef2854c5e1 100644
> --- a/include/linux/gunyah.h
> +++ b/include/linux/gunyah.h
> @@ -6,8 +6,10 @@
>   #ifndef _LINUX_GUNYAH_H
>   #define _LINUX_GUNYAH_H
>   
> +#include <linux/bitfield.h>
>   #include <linux/errno.h>
>   #include <linux/limits.h>
> +#include <linux/types.h>
>   
>   /******************************************************************************/
>   /* Common arch-independent definitions for Gunyah hypercalls                  */
> @@ -79,4 +81,35 @@ static inline int gh_remap_error(enum gh_error gh_error)
>   	}
>   }
>   
> +enum gh_api_feature {
> +	GH_API_FEATURE_DOORBELL,
> +	GH_API_FEATURE_MSGQUEUE,
> +	GH_API_FEATURE_VCPU,
> +	GH_API_FEATURE_MEMEXTENT,
> +};
> +
> +bool arch_is_gunyah_guest(void);
> +
> +u16 gh_api_version(void);
> +bool gh_api_has_feature(enum gh_api_feature feature);
gh_api_has_feature or arch_is_gunyah_guest is in this patch, this should 
probably moved to the respecitive patch that implements these functions.

--srini
> +
> +#define GUNYAH_API_V1			1
> +
> +#define GH_API_INFO_API_VERSION_MASK	GENMASK_ULL(13, 0)
> +#define GH_API_INFO_BIG_ENDIAN		BIT_ULL(14)
> +#define GH_API_INFO_IS_64BIT		BIT_ULL(15)
> +#define GH_API_INFO_VARIANT_MASK	GENMASK_ULL(63, 56)
> +
> +#define GH_IDENTIFY_DOORBELL			BIT_ULL(1)
> +#define GH_IDENTIFY_MSGQUEUE			BIT_ULL(2)
> +#define GH_IDENTIFY_VCPU			BIT_ULL(5)
> +#define GH_IDENTIFY_MEMEXTENT			BIT_ULL(6)
> +
> +struct gh_hypercall_hyp_identify_resp {
> +	u64 api_info;
> +	u64 flags[3];
> +};
> +
> +void gh_hypercall_hyp_identify(struct gh_hypercall_hyp_identify_resp *hyp_identity);
> +
>   #endif
Alex Elder Feb. 24, 2023, 12:09 a.m. UTC | #2 
On 2/14/23 3:12 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.
> 
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
>   arch/arm64/Kbuild                    |  1 +
>   arch/arm64/gunyah/Makefile           |  3 ++
>   arch/arm64/gunyah/gunyah_hypercall.c | 61 ++++++++++++++++++++++++++++
>   drivers/virt/Kconfig                 |  2 +
>   drivers/virt/gunyah/Kconfig          | 13 ++++++
>   include/linux/gunyah.h               | 33 +++++++++++++++
>   6 files changed, 113 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..f30d06ee80cf
> --- /dev/null
> +++ b/arch/arm64/gunyah/gunyah_hypercall.c
> @@ -0,0 +1,61 @@
> +// 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>
> +
> +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) */
> +};

Are these really UUIDs? Standard ones?  Define them using
the standard Linux way of doing it.  See <linux/uuid.h>.

> +
> +bool arch_is_gunyah_guest(void)
> +{
> +	struct arm_smccc_res res;
> +	u32 uid[4];
> +	int i;
> +
> +	arm_smccc_1_1_hvc(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res);
> +
> +	uid[0] = lower_32_bits(res.a0);
> +	uid[1] = lower_32_bits(res.a1);
> +	uid[2] = lower_32_bits(res.a2);
> +	uid[3] = lower_32_bits(res.a3);
> +
> +	for (i = 0; i < ARRAY_SIZE(gunyah_known_uuids); i++)
> +		if (!memcmp(uid, gunyah_known_uuids[i], sizeof(uid)))
> +			break;
> +
> +	return i != ARRAY_SIZE(gunyah_known_uuids);
> +}
> +EXPORT_SYMBOL_GPL(arch_is_gunyah_guest);
> +
> +#define GH_HYPERCALL(fn)	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_64, \
> +						   ARM_SMCCC_OWNER_VENDOR_HYP, \
> +						   fn)
> +
> +#define GH_HYPERCALL_HYP_IDENTIFY		GH_HYPERCALL(0x8000)
> +
> +/**
> + * gh_hypercall_hyp_identify() - Returns build information and feature flags
> + *                               supported by Gunyah.
> + * @hyp_identity: filled by the hypercall with the API info and feature flags.
> + */
> +void gh_hypercall_hyp_identify(struct gh_hypercall_hyp_identify_resp *hyp_identity)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_hvc(GH_HYPERCALL_HYP_IDENTIFY, &res);
> +
> +	hyp_identity->api_info = res.a0;
> +	hyp_identity->flags[0] = res.a1;
> +	hyp_identity->flags[1] = res.a2;
> +	hyp_identity->flags[2] = res.a3;
> +}
> +EXPORT_SYMBOL_GPL(gh_hypercall_hyp_identify);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Gunyah Hypervisor Hypercalls");
> diff --git a/drivers/virt/Kconfig b/drivers/virt/Kconfig
> index f79ab13a5c28..85bd6626ffc9 100644
> --- a/drivers/virt/Kconfig
> +++ b/drivers/virt/Kconfig
> @@ -54,4 +54,6 @@ source "drivers/virt/coco/sev-guest/Kconfig"
>   
>   source "drivers/virt/coco/tdx-guest/Kconfig"
>   
> +source "drivers/virt/gunyah/Kconfig"
> +
>   endif
> diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig
> new file mode 100644
> index 000000000000..1a737694c333
> --- /dev/null
> +++ b/drivers/virt/gunyah/Kconfig
> @@ -0,0 +1,13 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +
> +config GUNYAH
> +	tristate "Gunyah Virtualization drivers"
> +	depends on ARM64
> +	depends on MAILBOX
> +	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
> +	  services such as memory/device sharing, IRQ sharing, and so on.
> +
> +	  Say Y/M here to enable the drivers needed to interact in a Gunyah
> +	  virtual environment.
> diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
> index 59ef4c735ae8..3fef2854c5e1 100644
> --- a/include/linux/gunyah.h
> +++ b/include/linux/gunyah.h
> @@ -6,8 +6,10 @@
>   #ifndef _LINUX_GUNYAH_H
>   #define _LINUX_GUNYAH_H
>   
> +#include <linux/bitfield.h>
>   #include <linux/errno.h>
>   #include <linux/limits.h>
> +#include <linux/types.h>
>   
>   /******************************************************************************/
>   /* Common arch-independent definitions for Gunyah hypercalls                  */
> @@ -79,4 +81,35 @@ static inline int gh_remap_error(enum gh_error gh_error)
>   	}
>   }
>   
> +enum gh_api_feature {
> +	GH_API_FEATURE_DOORBELL,
> +	GH_API_FEATURE_MSGQUEUE,
> +	GH_API_FEATURE_VCPU,
> +	GH_API_FEATURE_MEMEXTENT,
> +};

Can't you reuse these symbols, so that the same set
represents the feature and the identify response?

I'm not sure what a good naming scheme would be, but
you could easily do:
enum gh_api_feature {
	GH_FEATURE_DOORBELL	= 1,
	GH_FEATURE_MSGQUEUE	= 2,
	GH_FEATURE_VCPU		= 5,
	GH_FEATURE_MEMEXTENT	= 6,
};

And then you could do:

bool gh_api_has_feature(enum gh_api_feature feature)
{
         switch (feature) {
         case GH_FEATURE_DOORBELL:
	case GH_FEATURES_MSGQUEUE:
	case GH_FEATURE_VCPU:
	case GH_FEATURE_MEMEXTENT:
		return !!(gunyah_api.flags[0] & BIT_ULL(feature));

	default:
		return false;
	}
}

> +
> +bool arch_is_gunyah_guest(void);
> +
> +u16 gh_api_version(void);
> +bool gh_api_has_feature(enum gh_api_feature feature);
> +
> +#define GUNYAH_API_V1			1
> +

Rather than _INFO_ here, maybe _IDENTIFY_?

Why is "API_" needed in these symbol names?

> +#define GH_API_INFO_API_VERSION_MASK	GENMASK_ULL(13, 0)
> +#define GH_API_INFO_BIG_ENDIAN		BIT_ULL(14)
> +#define GH_API_INFO_IS_64BIT		BIT_ULL(15)
> +#define GH_API_INFO_VARIANT_MASK	GENMASK_ULL(63, 56)
> +
> +#define GH_IDENTIFY_DOORBELL			BIT_ULL(1)
> +#define GH_IDENTIFY_MSGQUEUE			BIT_ULL(2)
> +#define GH_IDENTIFY_VCPU			BIT_ULL(5)
> +#define GH_IDENTIFY_MEMEXTENT			BIT_ULL(6)
> +
> +struct gh_hypercall_hyp_identify_resp {
> +	u64 api_info;
> +	u64 flags[3];
> +};
> +
> +void gh_hypercall_hyp_identify(struct gh_hypercall_hyp_identify_resp *hyp_identity);

Since this is a user space API, you *could* consider having
this function return an int.  Just in case there's a future
reason that a failure could occur, or that you want to
supply some other information.  If this truly doesn't make
sense, it's fine as-is...

> +
>   #endif
Elliot Berman March 2, 2023, 1:21 a.m. UTC | #3 
On 2/23/2023 4:09 PM, Alex Elder wrote:
> On 2/14/23 3:12 PM, Elliot Berman wrote:
>> +
>> +void gh_hypercall_hyp_identify(struct gh_hypercall_hyp_identify_resp 
>> *hyp_identity);
> 
> Since this is a user space API, you *could* consider having
> this function return an int.  Just in case there's a future
> reason that a failure could occur, or that you want to
> supply some other information.  If this truly doesn't make
> sense, it's fine as-is...
> 

I'm not sure what was meant by user space API. However, hypervisor API 
doesn't provision a return value. r0 is usually the return value for 
most other Gunyah hypercalls except for this one -- instead, it's the 
api_info field.

The other kind of error we could get is at hypercall "transport" layer, 
but the hvc instruction doesn't fail and if we ever change the hypercall 
transport, I'm sure there will be a lot of other changes to consider as 
well.

Thanks,
Elliot
diff mbox series

Patch

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..f30d06ee80cf
--- /dev/null
+++ b/arch/arm64/gunyah/gunyah_hypercall.c
@@ -0,0 +1,61 @@ 
+// 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>
+
+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) */
+};
+
+bool arch_is_gunyah_guest(void)
+{
+	struct arm_smccc_res res;
+	u32 uid[4];
+	int i;
+
+	arm_smccc_1_1_hvc(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res);
+
+	uid[0] = lower_32_bits(res.a0);
+	uid[1] = lower_32_bits(res.a1);
+	uid[2] = lower_32_bits(res.a2);
+	uid[3] = lower_32_bits(res.a3);
+
+	for (i = 0; i < ARRAY_SIZE(gunyah_known_uuids); i++)
+		if (!memcmp(uid, gunyah_known_uuids[i], sizeof(uid)))
+			break;
+
+	return i != ARRAY_SIZE(gunyah_known_uuids);
+}
+EXPORT_SYMBOL_GPL(arch_is_gunyah_guest);
+
+#define GH_HYPERCALL(fn)	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_64, \
+						   ARM_SMCCC_OWNER_VENDOR_HYP, \
+						   fn)
+
+#define GH_HYPERCALL_HYP_IDENTIFY		GH_HYPERCALL(0x8000)
+
+/**
+ * gh_hypercall_hyp_identify() - Returns build information and feature flags
+ *                               supported by Gunyah.
+ * @hyp_identity: filled by the hypercall with the API info and feature flags.
+ */
+void gh_hypercall_hyp_identify(struct gh_hypercall_hyp_identify_resp *hyp_identity)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_hvc(GH_HYPERCALL_HYP_IDENTIFY, &res);
+
+	hyp_identity->api_info = res.a0;
+	hyp_identity->flags[0] = res.a1;
+	hyp_identity->flags[1] = res.a2;
+	hyp_identity->flags[2] = res.a3;
+}
+EXPORT_SYMBOL_GPL(gh_hypercall_hyp_identify);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Gunyah Hypervisor Hypercalls");
diff --git a/drivers/virt/Kconfig b/drivers/virt/Kconfig
index f79ab13a5c28..85bd6626ffc9 100644
--- a/drivers/virt/Kconfig
+++ b/drivers/virt/Kconfig
@@ -54,4 +54,6 @@  source "drivers/virt/coco/sev-guest/Kconfig"
 
 source "drivers/virt/coco/tdx-guest/Kconfig"
 
+source "drivers/virt/gunyah/Kconfig"
+
 endif
diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig
new file mode 100644
index 000000000000..1a737694c333
--- /dev/null
+++ b/drivers/virt/gunyah/Kconfig
@@ -0,0 +1,13 @@ 
+# SPDX-License-Identifier: GPL-2.0-only
+
+config GUNYAH
+	tristate "Gunyah Virtualization drivers"
+	depends on ARM64
+	depends on MAILBOX
+	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
+	  services such as memory/device sharing, IRQ sharing, and so on.
+
+	  Say Y/M here to enable the drivers needed to interact in a Gunyah
+	  virtual environment.
diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
index 59ef4c735ae8..3fef2854c5e1 100644
--- a/include/linux/gunyah.h
+++ b/include/linux/gunyah.h
@@ -6,8 +6,10 @@ 
 #ifndef _LINUX_GUNYAH_H
 #define _LINUX_GUNYAH_H
 
+#include <linux/bitfield.h>
 #include <linux/errno.h>
 #include <linux/limits.h>
+#include <linux/types.h>
 
 /******************************************************************************/
 /* Common arch-independent definitions for Gunyah hypercalls                  */
@@ -79,4 +81,35 @@  static inline int gh_remap_error(enum gh_error gh_error)
 	}
 }
 
+enum gh_api_feature {
+	GH_API_FEATURE_DOORBELL,
+	GH_API_FEATURE_MSGQUEUE,
+	GH_API_FEATURE_VCPU,
+	GH_API_FEATURE_MEMEXTENT,
+};
+
+bool arch_is_gunyah_guest(void);
+
+u16 gh_api_version(void);
+bool gh_api_has_feature(enum gh_api_feature feature);
+
+#define GUNYAH_API_V1			1
+
+#define GH_API_INFO_API_VERSION_MASK	GENMASK_ULL(13, 0)
+#define GH_API_INFO_BIG_ENDIAN		BIT_ULL(14)
+#define GH_API_INFO_IS_64BIT		BIT_ULL(15)
+#define GH_API_INFO_VARIANT_MASK	GENMASK_ULL(63, 56)
+
+#define GH_IDENTIFY_DOORBELL			BIT_ULL(1)
+#define GH_IDENTIFY_MSGQUEUE			BIT_ULL(2)
+#define GH_IDENTIFY_VCPU			BIT_ULL(5)
+#define GH_IDENTIFY_MEMEXTENT			BIT_ULL(6)
+
+struct gh_hypercall_hyp_identify_resp {
+	u64 api_info;
+	u64 flags[3];
+};
+
+void gh_hypercall_hyp_identify(struct gh_hypercall_hyp_identify_resp *hyp_identity);
+
 #endif