From a06c3fad49a50d5d5eb078f93e70f4d3eca5d5a5 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 30 Aug 2024 14:01:45 +0100 Subject: [PATCH] drivers/virt: pkvm: Add initial support for running as a protected guest Implement a pKVM protected guest driver to probe the presence of pKVM and determine the memory protection granule using the HYP_MEMINFO hypercall. Acked-by: Marc Zyngier Link: https://lore.kernel.org/r/20240830130150.8568-3-will@kernel.org Signed-off-by: Will Deacon --- Documentation/virt/kvm/arm/hypercalls.rst | 22 +++++++++++ arch/arm64/include/asm/hypervisor.h | 7 ++++ drivers/virt/coco/Kconfig | 2 + drivers/virt/coco/Makefile | 1 + drivers/virt/coco/pkvm-guest/Kconfig | 10 +++++ drivers/virt/coco/pkvm-guest/Makefile | 2 + drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c | 37 +++++++++++++++++++ include/linux/arm-smccc.h | 7 ++++ 8 files changed, 88 insertions(+) create mode 100644 drivers/virt/coco/pkvm-guest/Kconfig create mode 100644 drivers/virt/coco/pkvm-guest/Makefile create mode 100644 drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c diff --git a/Documentation/virt/kvm/arm/hypercalls.rst b/Documentation/virt/kvm/arm/hypercalls.rst index 17be111f493f..16515eb42149 100644 --- a/Documentation/virt/kvm/arm/hypercalls.rst +++ b/Documentation/virt/kvm/arm/hypercalls.rst @@ -44,3 +44,25 @@ Provides a discovery mechanism for other KVM/arm64 hypercalls. ---------------------------------------- See ptp_kvm.rst + +``ARM_SMCCC_KVM_FUNC_HYP_MEMINFO`` +---------------------------------- + +Query the memory protection parameters for a pKVM protected virtual machine. + ++---------------------+-------------------------------------------------------------+ +| Presence: | Optional; pKVM protected guests only. | ++---------------------+-------------------------------------------------------------+ +| Calling convention: | HVC64 | ++---------------------+----------+--------------------------------------------------+ +| Function ID: | (uint32) | 0xC6000002 | ++---------------------+----------+----+---------------------------------------------+ +| Arguments: | (uint64) | R1 | Reserved / Must be zero | +| +----------+----+---------------------------------------------+ +| | (uint64) | R2 | Reserved / Must be zero | +| +----------+----+---------------------------------------------+ +| | (uint64) | R3 | Reserved / Must be zero | ++---------------------+----------+----+---------------------------------------------+ +| Return Values: | (int64) | R0 | ``INVALID_PARAMETER (-3)`` on error, else | +| | | | memory protection granule in bytes | ++---------------------+----------+----+---------------------------------------------+ diff --git a/arch/arm64/include/asm/hypervisor.h b/arch/arm64/include/asm/hypervisor.h index 8cab2ab535b7..409e239834d1 100644 --- a/arch/arm64/include/asm/hypervisor.h +++ b/arch/arm64/include/asm/hypervisor.h @@ -7,8 +7,15 @@ void kvm_init_hyp_services(void); bool kvm_arm_hyp_service_available(u32 func_id); +#ifdef CONFIG_ARM_PKVM_GUEST +void pkvm_init_hyp_services(void); +#else +static inline void pkvm_init_hyp_services(void) { }; +#endif + static inline void kvm_arch_init_hyp_services(void) { + pkvm_init_hyp_services(); }; #endif diff --git a/drivers/virt/coco/Kconfig b/drivers/virt/coco/Kconfig index 87d142c1f932..d9ff676bf48d 100644 --- a/drivers/virt/coco/Kconfig +++ b/drivers/virt/coco/Kconfig @@ -9,6 +9,8 @@ config TSM_REPORTS source "drivers/virt/coco/efi_secret/Kconfig" +source "drivers/virt/coco/pkvm-guest/Kconfig" + source "drivers/virt/coco/sev-guest/Kconfig" source "drivers/virt/coco/tdx-guest/Kconfig" diff --git a/drivers/virt/coco/Makefile b/drivers/virt/coco/Makefile index 18c1aba5edb7..b69c30c1c720 100644 --- a/drivers/virt/coco/Makefile +++ b/drivers/virt/coco/Makefile @@ -4,5 +4,6 @@ # obj-$(CONFIG_TSM_REPORTS) += tsm.o obj-$(CONFIG_EFI_SECRET) += efi_secret/ +obj-$(CONFIG_ARM_PKVM_GUEST) += pkvm-guest/ obj-$(CONFIG_SEV_GUEST) += sev-guest/ obj-$(CONFIG_INTEL_TDX_GUEST) += tdx-guest/ diff --git a/drivers/virt/coco/pkvm-guest/Kconfig b/drivers/virt/coco/pkvm-guest/Kconfig new file mode 100644 index 000000000000..d2f344f1f98f --- /dev/null +++ b/drivers/virt/coco/pkvm-guest/Kconfig @@ -0,0 +1,10 @@ +config ARM_PKVM_GUEST + bool "Arm pKVM protected guest driver" + depends on ARM64 + help + Protected guests running under the pKVM hypervisor on arm64 + are isolated from the host and must issue hypercalls to enable + interaction with virtual devices. This driver implements + support for probing and issuing these hypercalls. + + If unsure, say 'N'. diff --git a/drivers/virt/coco/pkvm-guest/Makefile b/drivers/virt/coco/pkvm-guest/Makefile new file mode 100644 index 000000000000..4bee24579423 --- /dev/null +++ b/drivers/virt/coco/pkvm-guest/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-$(CONFIG_ARM_PKVM_GUEST) += arm-pkvm-guest.o diff --git a/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c b/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c new file mode 100644 index 000000000000..a5148701d2f1 --- /dev/null +++ b/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c @@ -0,0 +1,37 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Support for the hypercall interface exposed to protected guests by + * pKVM. + * + * Author: Will Deacon + * Copyright (C) 2024 Google LLC + */ + +#include +#include +#include + +#include + +static size_t pkvm_granule; + +void pkvm_init_hyp_services(void) +{ + int i; + struct arm_smccc_res res; + const u32 funcs[] = { + ARM_SMCCC_KVM_FUNC_HYP_MEMINFO, + }; + + for (i = 0; i < ARRAY_SIZE(funcs); ++i) { + if (!kvm_arm_hyp_service_available(funcs[i])) + return; + } + + arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_HYP_MEMINFO_FUNC_ID, + 0, 0, 0, &res); + if (res.a0 > PAGE_SIZE) /* Includes error codes */ + return; + + pkvm_granule = res.a0; +} diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h index 083f85653716..16b6dcc54e02 100644 --- a/include/linux/arm-smccc.h +++ b/include/linux/arm-smccc.h @@ -115,6 +115,7 @@ /* KVM "vendor specific" services */ #define ARM_SMCCC_KVM_FUNC_FEATURES 0 #define ARM_SMCCC_KVM_FUNC_PTP 1 +#define ARM_SMCCC_KVM_FUNC_HYP_MEMINFO 2 #define ARM_SMCCC_KVM_FUNC_FEATURES_2 127 #define ARM_SMCCC_KVM_NUM_FUNCS 128 @@ -137,6 +138,12 @@ ARM_SMCCC_OWNER_VENDOR_HYP, \ ARM_SMCCC_KVM_FUNC_PTP) +#define ARM_SMCCC_VENDOR_HYP_KVM_HYP_MEMINFO_FUNC_ID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_64, \ + ARM_SMCCC_OWNER_VENDOR_HYP, \ + ARM_SMCCC_KVM_FUNC_HYP_MEMINFO) + /* ptp_kvm counter type ID */ #define KVM_PTP_VIRT_COUNTER 0 #define KVM_PTP_PHYS_COUNTER 1