| Message ID | 20221219225850.2397345-6-quic_eberman@quicinc.com |
|---|---|
| State | New |
| Headers | show |
| Series | Drivers for gunyah hypervisor | expand |
On 1/9/2023 1:34 PM, Alex Elder wrote: > On 12/19/22 4:58 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. > > The first is a "service", while the second is a "hypercall". > Can you explain the distinction? The sentence at the top > refers to both as "hypercalls". > I learned more details about this to answer your question. "get_uid()" is a standardized call that is ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID defined in include/arm-smccc.h. I'll use that. >> >> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com> >> --- >> MAINTAINERS | 2 + >> arch/arm64/Kbuild | 1 + >> arch/arm64/gunyah/Makefile | 1 + >> arch/arm64/gunyah/gunyah_hypercall.c | 69 ++++++++++++++++++++++++++++ >> drivers/virt/Kconfig | 1 + >> drivers/virt/gunyah/Kconfig | 12 +++++ >> include/linux/gunyah.h | 25 ++++++++++ >> 7 files changed, 111 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/MAINTAINERS b/MAINTAINERS >> index 74e76e0ab14d..36698df6b0e5 100644 >> --- a/MAINTAINERS >> +++ b/MAINTAINERS >> @@ -8941,6 +8941,8 @@ L: linux-arm-msm@vger.kernel.org >> S: Supported >> F: Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml >> F: Documentation/virt/gunyah/ >> +F: arch/arm64/gunyah/ >> +F: drivers/virt/gunyah/ >> F: include/linux/gunyah.h >> HABANALABS PCI DRIVER >> 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..9fbc720b6fb6 >> --- /dev/null >> +++ b/arch/arm64/gunyah/Makefile >> @@ -0,0 +1 @@ >> +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..0beb3123d650 >> --- /dev/null >> +++ b/arch/arm64/gunyah/gunyah_hypercall.c >> @@ -0,0 +1,69 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/* >> + * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights >> reserved. >> + */ >> + >> +#include <linux/arm-smccc.h> >> +#include <linux/module.h> >> +#include <linux/gunyah.h> >> + >> +#define GH_CALL_TYPE_PLATFORM_CALL 0 >> +#define GH_CALL_TYPE_HYPERCALL 2 >> +#define GH_CALL_TYPE_SERVICE 3 >> +#define GH_CALL_TYPE_SHIFT 14 >> +#define GH_CALL_FUNCTION_NUM_MASK 0x3fff > > A FN_ID is a 32-bit value. Are all 18 high-order bits considered > part of the call type? It might be good to specify that explicitly > by defining a mask for it. > With above in mind, I decided to simplify the macros and drop the TYPE field. >> + >> +#define GH_FN_ID(type, num) ((type) << GH_CALL_TYPE_SHIFT | ((num) >> & GH_CALL_FUNCTION_NUM_MASK)) >> + > > Is there any need for the endianness of these values to be specified? > Does Gunyah operate with a well-defined endianness? Is there any > chance a VM can run with an endianness different from Gunyah? I > see that the arm_smcc_* structures are defined without endianness. > (Sorry if these are dumb questions.) > All of the data transfers for hypercalls happen via registers, so endianness doesn't have impact here (there is no "low address" in a register). >> +#define GH_SERVICE(fn) ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, >> ARM_SMCCC_SMC_32, \ >> + ARM_SMCCC_OWNER_VENDOR_HYP, \ >> + GH_FN_ID(GH_CALL_TYPE_SERVICE, fn)) >> + >> +#define GH_HYPERCALL_CALL_UID GH_SERVICE(0x3f01) > > Perhaps 0x3f01 could be defined symbolically. > > However if this is the only place it's ever used, doing so > doesn't add much value (meaning, just do it the way you did). > >> + >> +#define GH_HYPERCALL(fn) ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, >> ARM_SMCCC_SMC_64, \ >> + ARM_SMCCC_OWNER_VENDOR_HYP, \ >> + GH_FN_ID(GH_CALL_TYPE_HYPERCALL, fn)) >> + >> +#define GH_HYPERCALL_HYP_IDENTIFY GH_HYPERCALL(0x0000) > > Will there be a growing set of well-known hypervisor call functions? > Perhaps 0x0000 should be defined symbolically. (Or not if it's only > used here.) > Yes, we would add growing set of well-known hypercalls. 0x0000 would only be used here. >> + >> +/** >> + * gh_hypercall_get_uid() - Returns a UID when running under a Gunyah >> hypervisor >> + * @uid: An array of 4 u32's (u32 uid[4];) >> + * >> + * Caller should compare the resulting UID to a list of known Gunyah >> UIDs to >> + * confirm that Linux is running as a guest of Gunyah. > > I presume that, if the returned UID isn't well-known, then no other > Gunyah-related calls are meaningful. Is that correct? > That's correct. >> + */ >> +void gh_hypercall_get_uid(u32 uid[4]) >> +{ >> + struct arm_smccc_res res; >> + >> + arm_smccc_1_1_hvc(GH_HYPERCALL_CALL_UID, &res); >> + >> + uid[0] = res.a0; >> + uid[1] = res.a1; >> + uid[2] = res.a2; >> + uid[3] = res.a3; > > I see in the definition of struct arm_smccc_res that the four > fields are unsigned long values. That differs from the u32 > array passed as argument. Are the resource IDs guaranteed to > be four 32-bit values? I personally prefer being explicit > about the upper 32-bits being discarded (though some don't > agree with that convention). > Done. >> +} >> +EXPORT_SYMBOL_GPL(gh_hypercall_get_uid); >> + >> +/** >> + * 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 87ef258cec64..259dc2be6cad 100644 >> --- a/drivers/virt/Kconfig >> +++ b/drivers/virt/Kconfig >> @@ -52,4 +52,5 @@ source "drivers/virt/coco/efi_secret/Kconfig" >> source "drivers/virt/coco/sev-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..127156a678a6 >> --- /dev/null >> +++ b/drivers/virt/gunyah/Kconfig >> @@ -0,0 +1,12 @@ >> +# SPDX-License-Identifier: GPL-2.0-only >> + >> +config GUNYAH > > Maybe config QCOM_GUNYAH? Will this ever run on hardware > other than Qualcomm's? > Yes, Gunyah can run on other hardware. We have support for QEMU and other hardware support is anticipated. >> + tristate "Gunyah Virtualization drivers" >> + depends on ARM64 >> + help >> + The Gunyah drivers are the helper interfaces that runs in a >> guest VM > > s/runs/run/ > >> + such as basic inter-VM IPC and signalingmechanisms, 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 824e20a11d27..2765d2b40198 100644 >> --- a/include/linux/gunyah.h >> +++ b/include/linux/gunyah.h >> @@ -6,6 +6,7 @@ >> #ifndef _GUNYAH_H >> #define _GUNYAH_H >> +#include <linux/bitfield.h> >> #include <linux/types.h> >> #include <linux/errno.h> >> @@ -71,4 +72,28 @@ static inline int gh_remap_error(int gh_error) >> } >> } >> +#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) >> + > > How are the GH_IDENTIFY bits below used? Are they encoded > in the three 64-bit flags fields in the response structure? > Does that mean only the first of those three is (currently) > used? > That's correct. >> +#define GH_IDENTIFY_PARTITION_CSPACE BIT_ULL(0) >> +#define GH_IDENTIFY_DOORBELL BIT_ULL(1) >> +#define GH_IDENTIFY_MSGQUEUE BIT_ULL(2) >> +#define GH_IDENTIFY_VIC BIT_ULL(3) >> +#define GH_IDENTIFY_VPM BIT_ULL(4) >> +#define GH_IDENTIFY_VCPU BIT_ULL(5) >> +#define GH_IDENTIFY_MEMEXTENT BIT_ULL(6) >> +#define GH_IDENTIFY_TRACE_CTRL BIT_ULL(7) >> + >> +struct gh_hypercall_hyp_identify_resp { >> + u64 api_info; >> + u64 flags[3]; >> +}; > > Again I'll ask about endianness. This is a response coming *from* > Gunyah. Is it guaranteed to use the same byte order convention as > the running operating system (Linux) guest? > Yes, that guarantee is there. Thanks, Elliot
On 1/10/23 11:56 AM, Elliot Berman wrote: >> Is there any need for the endianness of these values to be specified? >> Does Gunyah operate with a well-defined endianness? Is there any >> chance a VM can run with an endianness different from Gunyah? I >> see that the arm_smcc_* structures are defined without endianness. >> (Sorry if these are dumb questions.) >> > > All of the data transfers for hypercalls happen via registers, so > endianness doesn't have impact here (there is no "low address" in a > register). I don't believe that is technically true. Practically speaking, it's probably almost *always* little-endian. But for example, here: https://developer.arm.com/documentation/102376/0100/Alignment-and-endianness it says: Endianness In Armv8-A, instruction fetches are always treated as little-endian. For data accesses, it is IMPLEMENTATION DEFINED whether both little-endian and big-endian are supported. And if only one is supported, it is IMPLEMENTATION DEFINED which one is supported. For processors that support both big-endian and little-endian, endianness is configured per Exception level. Perhaps that last sentence doesn't apply to HVC exceptions but to me it *sounds* like it's at least possible for a VM to be running with an endianness that differs from the hypervisor (perhaps not other VMs though.) This is not an area of expertise of mine, so I would love for someone who knows more to correct me if I'm wrong. It's likely to be fine as-is, but (other than the work to do it and get it right) it doesn't hurt to specify it and do the conversions as data is passes to/from the hypervisor. -Alex
On 1/10/23 11:56 AM, Elliot Berman wrote: >>> 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. >> >> The first is a "service", while the second is a "hypercall". >> Can you explain the distinction? The sentence at the top >> refers to both as "hypercalls". >> > > I learned more details about this to answer your question. "get_uid()" > is a standardized call that is ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID > defined in include/arm-smccc.h. I'll use that. You didn't really explain the distinction between hypercall and service in Gunyah. Both are encoded as "vendor specific hypervisor service calls" according to the SVCCC specification. I haven't found where ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID gets handled, but I accept your answer that it's basically a standard call. The "get UID" is the only one that's defined as a Gunyah "service"; the rest are hypercalls. It's not a big deal, I just noticed the difference and was curious about it. -Alex
On 1/17/2023 11:20 AM, Alex Elder wrote: > On 1/10/23 11:56 AM, Elliot Berman wrote: >>>> 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. >>> >>> The first is a "service", while the second is a "hypercall". >>> Can you explain the distinction? The sentence at the top >>> refers to both as "hypercalls". >>> >> >> I learned more details about this to answer your question. "get_uid()" >> is a standardized call that is ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID >> defined in include/arm-smccc.h. I'll use that. > > You didn't really explain the distinction between hypercall > and service in Gunyah. Both are encoded as "vendor specific > hypervisor service calls" according to the SVCCC specification. > I haven't found where ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID > gets handled, but I accept your answer that it's basically > a standard call. The "get UID" is the only one that's defined > as a Gunyah "service"; the rest are hypercalls. > This came from a Gunyah implementation detail that separates standard (service) calls from the non-standard calls. I was following the distinction from Gunyah code not realizing that it's actually a standardized call that Linux would already have support for. Thanks, Elliot > It's not a big deal, I just noticed the difference and was > curious about it. > > -Alex
diff --git a/MAINTAINERS b/MAINTAINERS index 74e76e0ab14d..36698df6b0e5 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -8941,6 +8941,8 @@ L: linux-arm-msm@vger.kernel.org S: Supported F: Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml F: Documentation/virt/gunyah/ +F: arch/arm64/gunyah/ +F: drivers/virt/gunyah/ F: include/linux/gunyah.h HABANALABS PCI DRIVER 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-$(CONFIG_CRYPTO) += crypto/ # for cleaning diff --git a/arch/arm64/gunyah/Makefile b/arch/arm64/gunyah/Makefile new file mode 100644 index 000000000000..9fbc720b6fb6 --- /dev/null +++ b/arch/arm64/gunyah/Makefile @@ -0,0 +1 @@ +obj-$(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..0beb3123d650 --- /dev/null +++ b/arch/arm64/gunyah/gunyah_hypercall.c @@ -0,0 +1,69 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved. + */ + +#include <linux/arm-smccc.h> +#include <linux/module.h> +#include <linux/gunyah.h> + +#define GH_CALL_TYPE_PLATFORM_CALL 0 +#define GH_CALL_TYPE_HYPERCALL 2 +#define GH_CALL_TYPE_SERVICE 3 +#define GH_CALL_TYPE_SHIFT 14 +#define GH_CALL_FUNCTION_NUM_MASK 0x3fff + +#define GH_FN_ID(type, num) ((type) << GH_CALL_TYPE_SHIFT | ((num) & GH_CALL_FUNCTION_NUM_MASK)) + +#define GH_SERVICE(fn) ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_VENDOR_HYP, \ + GH_FN_ID(GH_CALL_TYPE_SERVICE, fn)) + +#define GH_HYPERCALL_CALL_UID GH_SERVICE(0x3f01) + +#define GH_HYPERCALL(fn) ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_64, \ + ARM_SMCCC_OWNER_VENDOR_HYP, \ + GH_FN_ID(GH_CALL_TYPE_HYPERCALL, fn)) + +#define GH_HYPERCALL_HYP_IDENTIFY GH_HYPERCALL(0x0000) + +/** + * gh_hypercall_get_uid() - Returns a UID when running under a Gunyah hypervisor + * @uid: An array of 4 u32's (u32 uid[4];) + * + * Caller should compare the resulting UID to a list of known Gunyah UIDs to + * confirm that Linux is running as a guest of Gunyah. + */ +void gh_hypercall_get_uid(u32 uid[4]) +{ + struct arm_smccc_res res; + + arm_smccc_1_1_hvc(GH_HYPERCALL_CALL_UID, &res); + + uid[0] = res.a0; + uid[1] = res.a1; + uid[2] = res.a2; + uid[3] = res.a3; +} +EXPORT_SYMBOL_GPL(gh_hypercall_get_uid); + +/** + * 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 87ef258cec64..259dc2be6cad 100644 --- a/drivers/virt/Kconfig +++ b/drivers/virt/Kconfig @@ -52,4 +52,5 @@ source "drivers/virt/coco/efi_secret/Kconfig" source "drivers/virt/coco/sev-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..127156a678a6 --- /dev/null +++ b/drivers/virt/gunyah/Kconfig @@ -0,0 +1,12 @@ +# SPDX-License-Identifier: GPL-2.0-only + +config GUNYAH + tristate "Gunyah Virtualization drivers" + depends on ARM64 + help + The Gunyah drivers are the helper interfaces that runs 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 824e20a11d27..2765d2b40198 100644 --- a/include/linux/gunyah.h +++ b/include/linux/gunyah.h @@ -6,6 +6,7 @@ #ifndef _GUNYAH_H #define _GUNYAH_H +#include <linux/bitfield.h> #include <linux/types.h> #include <linux/errno.h> @@ -71,4 +72,28 @@ static inline int gh_remap_error(int gh_error) } } +#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_PARTITION_CSPACE BIT_ULL(0) +#define GH_IDENTIFY_DOORBELL BIT_ULL(1) +#define GH_IDENTIFY_MSGQUEUE BIT_ULL(2) +#define GH_IDENTIFY_VIC BIT_ULL(3) +#define GH_IDENTIFY_VPM BIT_ULL(4) +#define GH_IDENTIFY_VCPU BIT_ULL(5) +#define GH_IDENTIFY_MEMEXTENT BIT_ULL(6) +#define GH_IDENTIFY_TRACE_CTRL BIT_ULL(7) + +struct gh_hypercall_hyp_identify_resp { + u64 api_info; + u64 flags[3]; +}; + +void gh_hypercall_get_uid(u32 uid[4]); +void gh_hypercall_hyp_identify(struct gh_hypercall_hyp_identify_resp *hyp_identity); + #endif
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> --- MAINTAINERS | 2 + arch/arm64/Kbuild | 1 + arch/arm64/gunyah/Makefile | 1 + arch/arm64/gunyah/gunyah_hypercall.c | 69 ++++++++++++++++++++++++++++ drivers/virt/Kconfig | 1 + drivers/virt/gunyah/Kconfig | 12 +++++ include/linux/gunyah.h | 25 ++++++++++ 7 files changed, 111 insertions(+) create mode 100644 arch/arm64/gunyah/Makefile create mode 100644 arch/arm64/gunyah/gunyah_hypercall.c create mode 100644 drivers/virt/gunyah/Kconfig