From 0ba5b4ba61781f1eca843d9e5d499da329a8a275 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 30 Aug 2024 14:01:44 +0100 Subject: [PATCH 1/7] firmware/smccc: Call arch-specific hook on discovering KVM services arm64 will soon require its own callback to initialise services that are only available on this architecture. Introduce a hook that can be overloaded by the architecture. Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20240830130150.8568-2-will@kernel.org Signed-off-by: Will Deacon --- arch/arm/include/asm/hypervisor.h | 2 ++ arch/arm64/include/asm/hypervisor.h | 4 ++++ drivers/firmware/smccc/kvm_guest.c | 2 ++ 3 files changed, 8 insertions(+) diff --git a/arch/arm/include/asm/hypervisor.h b/arch/arm/include/asm/hypervisor.h index bd61502b9715..8a648e506540 100644 --- a/arch/arm/include/asm/hypervisor.h +++ b/arch/arm/include/asm/hypervisor.h @@ -7,4 +7,6 @@ void kvm_init_hyp_services(void); bool kvm_arm_hyp_service_available(u32 func_id); +static inline void kvm_arch_init_hyp_services(void) { }; + #endif diff --git a/arch/arm64/include/asm/hypervisor.h b/arch/arm64/include/asm/hypervisor.h index 0ae427f352c8..8cab2ab535b7 100644 --- a/arch/arm64/include/asm/hypervisor.h +++ b/arch/arm64/include/asm/hypervisor.h @@ -7,4 +7,8 @@ void kvm_init_hyp_services(void); bool kvm_arm_hyp_service_available(u32 func_id); +static inline void kvm_arch_init_hyp_services(void) +{ +}; + #endif diff --git a/drivers/firmware/smccc/kvm_guest.c b/drivers/firmware/smccc/kvm_guest.c index 89a68e7eeaa6..f3319be20b36 100644 --- a/drivers/firmware/smccc/kvm_guest.c +++ b/drivers/firmware/smccc/kvm_guest.c @@ -39,6 +39,8 @@ void __init kvm_init_hyp_services(void) pr_info("hypervisor services detected (0x%08lx 0x%08lx 0x%08lx 0x%08lx)\n", res.a3, res.a2, res.a1, res.a0); + + kvm_arch_init_hyp_services(); } bool kvm_arm_hyp_service_available(u32 func_id) From a06c3fad49a50d5d5eb078f93e70f4d3eca5d5a5 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 30 Aug 2024 14:01:45 +0100 Subject: [PATCH 2/7] 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 From e7bafbf7177750e6643941473b343ed72fc5a100 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 30 Aug 2024 14:01:46 +0100 Subject: [PATCH 3/7] arm64: mm: Add top-level dispatcher for internal mem_encrypt API Implementing the internal mem_encrypt API for arm64 depends entirely on the Confidential Computing environment in which the kernel is running. Introduce a simple dispatcher so that backend hooks can be registered depending upon the environment in which the kernel finds itself. Reviewed-by: Catalin Marinas Reviewed-by: Steven Price Acked-by: Marc Zyngier Link: https://lore.kernel.org/r/20240830130150.8568-4-will@kernel.org Signed-off-by: Will Deacon --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/mem_encrypt.h | 15 +++++++++ arch/arm64/include/asm/set_memory.h | 1 + arch/arm64/mm/Makefile | 2 +- arch/arm64/mm/mem_encrypt.c | 50 ++++++++++++++++++++++++++++ 5 files changed, 68 insertions(+), 1 deletion(-) create mode 100644 arch/arm64/include/asm/mem_encrypt.h create mode 100644 arch/arm64/mm/mem_encrypt.c diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index a2f8ff354ca6..164858120191 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -34,6 +34,7 @@ config ARM64 select ARCH_HAS_KERNEL_FPU_SUPPORT if KERNEL_MODE_NEON select ARCH_HAS_KEEPINITRD select ARCH_HAS_MEMBARRIER_SYNC_CORE + select ARCH_HAS_MEM_ENCRYPT select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE select ARCH_HAS_PTE_DEVMAP diff --git a/arch/arm64/include/asm/mem_encrypt.h b/arch/arm64/include/asm/mem_encrypt.h new file mode 100644 index 000000000000..b0c9a86b13a4 --- /dev/null +++ b/arch/arm64/include/asm/mem_encrypt.h @@ -0,0 +1,15 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef __ASM_MEM_ENCRYPT_H +#define __ASM_MEM_ENCRYPT_H + +struct arm64_mem_crypt_ops { + int (*encrypt)(unsigned long addr, int numpages); + int (*decrypt)(unsigned long addr, int numpages); +}; + +int arm64_mem_crypt_ops_register(const struct arm64_mem_crypt_ops *ops); + +int set_memory_encrypted(unsigned long addr, int numpages); +int set_memory_decrypted(unsigned long addr, int numpages); + +#endif /* __ASM_MEM_ENCRYPT_H */ diff --git a/arch/arm64/include/asm/set_memory.h b/arch/arm64/include/asm/set_memory.h index 0f740b781187..917761feeffd 100644 --- a/arch/arm64/include/asm/set_memory.h +++ b/arch/arm64/include/asm/set_memory.h @@ -3,6 +3,7 @@ #ifndef _ASM_ARM64_SET_MEMORY_H #define _ASM_ARM64_SET_MEMORY_H +#include #include bool can_set_direct_map(void); diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile index 60454256945b..2fc8c6dd0407 100644 --- a/arch/arm64/mm/Makefile +++ b/arch/arm64/mm/Makefile @@ -1,7 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 obj-y := dma-mapping.o extable.o fault.o init.o \ cache.o copypage.o flush.o \ - ioremap.o mmap.o pgd.o mmu.o \ + ioremap.o mmap.o pgd.o mem_encrypt.o mmu.o \ context.o proc.o pageattr.o fixmap.o obj-$(CONFIG_ARM64_CONTPTE) += contpte.o obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o diff --git a/arch/arm64/mm/mem_encrypt.c b/arch/arm64/mm/mem_encrypt.c new file mode 100644 index 000000000000..ee3c0ab04384 --- /dev/null +++ b/arch/arm64/mm/mem_encrypt.c @@ -0,0 +1,50 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Implementation of the memory encryption/decryption API. + * + * Since the low-level details of the operation depend on the + * Confidential Computing environment (e.g. pKVM, CCA, ...), this just + * acts as a top-level dispatcher to whatever hooks may have been + * registered. + * + * Author: Will Deacon + * Copyright (C) 2024 Google LLC + * + * "Hello, boils and ghouls!" + */ + +#include +#include +#include +#include + +#include + +static const struct arm64_mem_crypt_ops *crypt_ops; + +int arm64_mem_crypt_ops_register(const struct arm64_mem_crypt_ops *ops) +{ + if (WARN_ON(crypt_ops)) + return -EBUSY; + + crypt_ops = ops; + return 0; +} + +int set_memory_encrypted(unsigned long addr, int numpages) +{ + if (likely(!crypt_ops) || WARN_ON(!PAGE_ALIGNED(addr))) + return 0; + + return crypt_ops->encrypt(addr, numpages); +} +EXPORT_SYMBOL_GPL(set_memory_encrypted); + +int set_memory_decrypted(unsigned long addr, int numpages) +{ + if (likely(!crypt_ops) || WARN_ON(!PAGE_ALIGNED(addr))) + return 0; + + return crypt_ops->decrypt(addr, numpages); +} +EXPORT_SYMBOL_GPL(set_memory_decrypted); From ebc59b120c588156feb7ce194a9636584ced18ba Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 30 Aug 2024 14:01:47 +0100 Subject: [PATCH 4/7] drivers/virt: pkvm: Hook up mem_encrypt API using pKVM hypercalls If we detect the presence of pKVM's SHARE and UNSHARE hypercalls, then register a backend implementation of the mem_encrypt API so that things like DMA buffers can be shared appropriately with the host. Acked-by: Marc Zyngier Link: https://lore.kernel.org/r/20240830130150.8568-5-will@kernel.org Signed-off-by: Will Deacon --- Documentation/virt/kvm/arm/hypercalls.rst | 50 +++++++++++++++++ drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c | 55 +++++++++++++++++++ include/linux/arm-smccc.h | 14 +++++ 3 files changed, 119 insertions(+) diff --git a/Documentation/virt/kvm/arm/hypercalls.rst b/Documentation/virt/kvm/arm/hypercalls.rst index 16515eb42149..c42580e71bf8 100644 --- a/Documentation/virt/kvm/arm/hypercalls.rst +++ b/Documentation/virt/kvm/arm/hypercalls.rst @@ -66,3 +66,53 @@ Query the memory protection parameters for a pKVM protected virtual machine. | Return Values: | (int64) | R0 | ``INVALID_PARAMETER (-3)`` on error, else | | | | | memory protection granule in bytes | +---------------------+----------+----+---------------------------------------------+ + +``ARM_SMCCC_KVM_FUNC_MEM_SHARE`` +-------------------------------- + +Share a region of memory with the KVM host, granting it read, write and execute +permissions. The size of the region is equal to the memory protection granule +advertised by ``ARM_SMCCC_KVM_FUNC_HYP_MEMINFO``. + ++---------------------+-------------------------------------------------------------+ +| Presence: | Optional; pKVM protected guests only. | ++---------------------+-------------------------------------------------------------+ +| Calling convention: | HVC64 | ++---------------------+----------+--------------------------------------------------+ +| Function ID: | (uint32) | 0xC6000003 | ++---------------------+----------+----+---------------------------------------------+ +| Arguments: | (uint64) | R1 | Base IPA of memory region to share | +| +----------+----+---------------------------------------------+ +| | (uint64) | R2 | Reserved / Must be zero | +| +----------+----+---------------------------------------------+ +| | (uint64) | R3 | Reserved / Must be zero | ++---------------------+----------+----+---------------------------------------------+ +| Return Values: | (int64) | R0 | ``SUCCESS (0)`` | +| | | +---------------------------------------------+ +| | | | ``INVALID_PARAMETER (-3)`` | ++---------------------+----------+----+---------------------------------------------+ + +``ARM_SMCCC_KVM_FUNC_MEM_UNSHARE`` +---------------------------------- + +Revoke access permission from the KVM host to a memory region previously shared +with ``ARM_SMCCC_KVM_FUNC_MEM_SHARE``. The size of the region is equal to the +memory protection granule advertised by ``ARM_SMCCC_KVM_FUNC_HYP_MEMINFO``. + ++---------------------+-------------------------------------------------------------+ +| Presence: | Optional; pKVM protected guests only. | ++---------------------+-------------------------------------------------------------+ +| Calling convention: | HVC64 | ++---------------------+----------+--------------------------------------------------+ +| Function ID: | (uint32) | 0xC6000004 | ++---------------------+----------+----+---------------------------------------------+ +| Arguments: | (uint64) | R1 | Base IPA of memory region to unshare | +| +----------+----+---------------------------------------------+ +| | (uint64) | R2 | Reserved / Must be zero | +| +----------+----+---------------------------------------------+ +| | (uint64) | R3 | Reserved / Must be zero | ++---------------------+----------+----+---------------------------------------------+ +| Return Values: | (int64) | R0 | ``SUCCESS (0)`` | +| | | +---------------------------------------------+ +| | | | ``INVALID_PARAMETER (-3)`` | ++---------------------+----------+----+---------------------------------------------+ diff --git a/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c b/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c index a5148701d2f1..8256cf68fd76 100644 --- a/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c +++ b/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c @@ -9,18 +9,72 @@ #include #include +#include #include #include static size_t pkvm_granule; +static int arm_smccc_do_one_page(u32 func_id, phys_addr_t phys) +{ + phys_addr_t end = phys + PAGE_SIZE; + + while (phys < end) { + struct arm_smccc_res res; + + arm_smccc_1_1_invoke(func_id, phys, 0, 0, &res); + if (res.a0 != SMCCC_RET_SUCCESS) + return -EPERM; + + phys += pkvm_granule; + } + + return 0; +} + +static int __set_memory_range(u32 func_id, unsigned long start, int numpages) +{ + void *addr = (void *)start, *end = addr + numpages * PAGE_SIZE; + + while (addr < end) { + int err; + + err = arm_smccc_do_one_page(func_id, virt_to_phys(addr)); + if (err) + return err; + + addr += PAGE_SIZE; + } + + return 0; +} + +static int pkvm_set_memory_encrypted(unsigned long addr, int numpages) +{ + return __set_memory_range(ARM_SMCCC_VENDOR_HYP_KVM_MEM_UNSHARE_FUNC_ID, + addr, numpages); +} + +static int pkvm_set_memory_decrypted(unsigned long addr, int numpages) +{ + return __set_memory_range(ARM_SMCCC_VENDOR_HYP_KVM_MEM_SHARE_FUNC_ID, + addr, numpages); +} + +static const struct arm64_mem_crypt_ops pkvm_crypt_ops = { + .encrypt = pkvm_set_memory_encrypted, + .decrypt = pkvm_set_memory_decrypted, +}; + void pkvm_init_hyp_services(void) { int i; struct arm_smccc_res res; const u32 funcs[] = { ARM_SMCCC_KVM_FUNC_HYP_MEMINFO, + ARM_SMCCC_KVM_FUNC_MEM_SHARE, + ARM_SMCCC_KVM_FUNC_MEM_UNSHARE, }; for (i = 0; i < ARRAY_SIZE(funcs); ++i) { @@ -34,4 +88,5 @@ void pkvm_init_hyp_services(void) return; pkvm_granule = res.a0; + arm64_mem_crypt_ops_register(&pkvm_crypt_ops); } diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h index 16b6dcc54e02..9cb7c95920b0 100644 --- a/include/linux/arm-smccc.h +++ b/include/linux/arm-smccc.h @@ -116,6 +116,8 @@ #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_MEM_SHARE 3 +#define ARM_SMCCC_KVM_FUNC_MEM_UNSHARE 4 #define ARM_SMCCC_KVM_FUNC_FEATURES_2 127 #define ARM_SMCCC_KVM_NUM_FUNCS 128 @@ -144,6 +146,18 @@ ARM_SMCCC_OWNER_VENDOR_HYP, \ ARM_SMCCC_KVM_FUNC_HYP_MEMINFO) +#define ARM_SMCCC_VENDOR_HYP_KVM_MEM_SHARE_FUNC_ID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_64, \ + ARM_SMCCC_OWNER_VENDOR_HYP, \ + ARM_SMCCC_KVM_FUNC_MEM_SHARE) + +#define ARM_SMCCC_VENDOR_HYP_KVM_MEM_UNSHARE_FUNC_ID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_64, \ + ARM_SMCCC_OWNER_VENDOR_HYP, \ + ARM_SMCCC_KVM_FUNC_MEM_UNSHARE) + /* ptp_kvm counter type ID */ #define KVM_PTP_VIRT_COUNTER 0 #define KVM_PTP_PHYS_COUNTER 1 From c86fa3470c1026e9f63a93e8885ea51ef99fae35 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 30 Aug 2024 14:01:48 +0100 Subject: [PATCH 5/7] arm64: mm: Add confidential computing hook to ioremap_prot() Confidential Computing environments such as pKVM and Arm's CCA distinguish between shared (i.e. emulated) and private (i.e. assigned) MMIO regions. Introduce a hook into our implementation of ioremap_prot() so that MMIO regions can be shared if necessary. Reviewed-by: Catalin Marinas Reviewed-by: Steven Price Acked-by: Marc Zyngier Link: https://lore.kernel.org/r/20240830130150.8568-6-will@kernel.org Signed-off-by: Will Deacon --- arch/arm64/include/asm/io.h | 4 ++++ arch/arm64/mm/ioremap.c | 23 ++++++++++++++++++++++- 2 files changed, 26 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h index 41fd90895dfc..1ada23a6ec19 100644 --- a/arch/arm64/include/asm/io.h +++ b/arch/arm64/include/asm/io.h @@ -271,6 +271,10 @@ __iowrite64_copy(void __iomem *to, const void *from, size_t count) * I/O memory mapping functions. */ +typedef int (*ioremap_prot_hook_t)(phys_addr_t phys_addr, size_t size, + pgprot_t *prot); +int arm64_ioremap_prot_hook_register(const ioremap_prot_hook_t hook); + #define ioremap_prot ioremap_prot #define _PAGE_IOREMAP PROT_DEVICE_nGnRE diff --git a/arch/arm64/mm/ioremap.c b/arch/arm64/mm/ioremap.c index 269f2f63ab7d..6cc0b7e7eb03 100644 --- a/arch/arm64/mm/ioremap.c +++ b/arch/arm64/mm/ioremap.c @@ -3,10 +3,22 @@ #include #include +static ioremap_prot_hook_t ioremap_prot_hook; + +int arm64_ioremap_prot_hook_register(ioremap_prot_hook_t hook) +{ + if (WARN_ON(ioremap_prot_hook)) + return -EBUSY; + + ioremap_prot_hook = hook; + return 0; +} + void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size, unsigned long prot) { unsigned long last_addr = phys_addr + size - 1; + pgprot_t pgprot = __pgprot(prot); /* Don't allow outside PHYS_MASK */ if (last_addr & ~PHYS_MASK) @@ -16,7 +28,16 @@ void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size, if (WARN_ON(pfn_is_map_memory(__phys_to_pfn(phys_addr)))) return NULL; - return generic_ioremap_prot(phys_addr, size, __pgprot(prot)); + /* + * If a hook is registered (e.g. for confidential computing + * purposes), call that now and barf if it fails. + */ + if (unlikely(ioremap_prot_hook) && + WARN_ON(ioremap_prot_hook(phys_addr, size, &pgprot))) { + return NULL; + } + + return generic_ioremap_prot(phys_addr, size, pgprot); } EXPORT_SYMBOL(ioremap_prot); From 0f12694958001c96bda811473fdb23f333c6d3ca Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 30 Aug 2024 14:01:49 +0100 Subject: [PATCH 6/7] drivers/virt: pkvm: Intercept ioremap using pKVM MMIO_GUARD hypercall Hook up pKVM's MMIO_GUARD hypercall so that ioremap() and friends will register the target physical address as MMIO with the hypervisor, allowing guest exits to that page to be emulated by the host with full syndrome information. Acked-by: Marc Zyngier Link: https://lore.kernel.org/r/20240830130150.8568-7-will@kernel.org Signed-off-by: Will Deacon --- Documentation/virt/kvm/arm/hypercalls.rst | 26 ++++++++++++++ drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c | 35 +++++++++++++++++++ include/linux/arm-smccc.h | 7 ++++ 3 files changed, 68 insertions(+) diff --git a/Documentation/virt/kvm/arm/hypercalls.rst b/Documentation/virt/kvm/arm/hypercalls.rst index c42580e71bf8..af7bc2c2e0cb 100644 --- a/Documentation/virt/kvm/arm/hypercalls.rst +++ b/Documentation/virt/kvm/arm/hypercalls.rst @@ -116,3 +116,29 @@ memory protection granule advertised by ``ARM_SMCCC_KVM_FUNC_HYP_MEMINFO``. | | | +---------------------------------------------+ | | | | ``INVALID_PARAMETER (-3)`` | +---------------------+----------+----+---------------------------------------------+ + +``ARM_SMCCC_KVM_FUNC_MMIO_GUARD`` +---------------------------------- + +Request that a given memory region is handled as MMIO by the hypervisor, +allowing accesses to this region to be emulated by the KVM host. The size of the +region is equal to the memory protection granule advertised by +``ARM_SMCCC_KVM_FUNC_HYP_MEMINFO``. + ++---------------------+-------------------------------------------------------------+ +| Presence: | Optional; pKVM protected guests only. | ++---------------------+-------------------------------------------------------------+ +| Calling convention: | HVC64 | ++---------------------+----------+--------------------------------------------------+ +| Function ID: | (uint32) | 0xC6000007 | ++---------------------+----------+----+---------------------------------------------+ +| Arguments: | (uint64) | R1 | Base IPA of MMIO memory region | +| +----------+----+---------------------------------------------+ +| | (uint64) | R2 | Reserved / Must be zero | +| +----------+----+---------------------------------------------+ +| | (uint64) | R3 | Reserved / Must be zero | ++---------------------+----------+----+---------------------------------------------+ +| Return Values: | (int64) | R0 | ``SUCCESS (0)`` | +| | | +---------------------------------------------+ +| | | | ``INVALID_PARAMETER (-3)`` | ++---------------------+----------+----+---------------------------------------------+ diff --git a/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c b/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c index 8256cf68fd76..56a3859dda8a 100644 --- a/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c +++ b/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c @@ -9,8 +9,10 @@ #include #include +#include #include #include +#include #include @@ -67,6 +69,36 @@ static const struct arm64_mem_crypt_ops pkvm_crypt_ops = { .decrypt = pkvm_set_memory_decrypted, }; +static int mmio_guard_ioremap_hook(phys_addr_t phys, size_t size, + pgprot_t *prot) +{ + phys_addr_t end; + pteval_t protval = pgprot_val(*prot); + + /* + * We only expect MMIO emulation for regions mapped with device + * attributes. + */ + if (protval != PROT_DEVICE_nGnRE && protval != PROT_DEVICE_nGnRnE) + return 0; + + phys = PAGE_ALIGN_DOWN(phys); + end = phys + PAGE_ALIGN(size); + + while (phys < end) { + const int func_id = ARM_SMCCC_VENDOR_HYP_KVM_MMIO_GUARD_FUNC_ID; + int err; + + err = arm_smccc_do_one_page(func_id, phys); + if (err) + return err; + + phys += PAGE_SIZE; + } + + return 0; +} + void pkvm_init_hyp_services(void) { int i; @@ -89,4 +121,7 @@ void pkvm_init_hyp_services(void) pkvm_granule = res.a0; arm64_mem_crypt_ops_register(&pkvm_crypt_ops); + + if (kvm_arm_hyp_service_available(ARM_SMCCC_KVM_FUNC_MMIO_GUARD)) + arm64_ioremap_prot_hook_register(&mmio_guard_ioremap_hook); } diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h index 9cb7c95920b0..e93c1f7cea70 100644 --- a/include/linux/arm-smccc.h +++ b/include/linux/arm-smccc.h @@ -118,6 +118,7 @@ #define ARM_SMCCC_KVM_FUNC_HYP_MEMINFO 2 #define ARM_SMCCC_KVM_FUNC_MEM_SHARE 3 #define ARM_SMCCC_KVM_FUNC_MEM_UNSHARE 4 +#define ARM_SMCCC_KVM_FUNC_MMIO_GUARD 7 #define ARM_SMCCC_KVM_FUNC_FEATURES_2 127 #define ARM_SMCCC_KVM_NUM_FUNCS 128 @@ -158,6 +159,12 @@ ARM_SMCCC_OWNER_VENDOR_HYP, \ ARM_SMCCC_KVM_FUNC_MEM_UNSHARE) +#define ARM_SMCCC_VENDOR_HYP_KVM_MMIO_GUARD_FUNC_ID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_64, \ + ARM_SMCCC_OWNER_VENDOR_HYP, \ + ARM_SMCCC_KVM_FUNC_MMIO_GUARD) + /* ptp_kvm counter type ID */ #define KVM_PTP_VIRT_COUNTER 0 #define KVM_PTP_PHYS_COUNTER 1 From 21be9f7110d4c044c2b49bafbd7246335f236221 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 30 Aug 2024 14:01:50 +0100 Subject: [PATCH 7/7] arm64: smccc: Reserve block of KVM "vendor" services for pKVM hypercalls pKVM relies on hypercalls to expose services such as memory sharing to protected guests. Tentatively allocate a block of 58 hypercalls (i.e. fill the remaining space in the first 64 function IDs) for pKVM usage, as future extensions such as pvIOMMU support, range-based memory sharing and validation of assigned devices will require additional services. Suggested-by: Marc Zyngier Link: https://lore.kernel.org/r/86a5h5yg5y.wl-maz@kernel.org Acked-by: Marc Zyngier Link: https://lore.kernel.org/r/20240830130150.8568-8-will@kernel.org Signed-off-by: Will Deacon --- include/linux/arm-smccc.h | 60 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h index e93c1f7cea70..f59099a213d0 100644 --- a/include/linux/arm-smccc.h +++ b/include/linux/arm-smccc.h @@ -115,10 +115,70 @@ /* KVM "vendor specific" services */ #define ARM_SMCCC_KVM_FUNC_FEATURES 0 #define ARM_SMCCC_KVM_FUNC_PTP 1 +/* Start of pKVM hypercall range */ #define ARM_SMCCC_KVM_FUNC_HYP_MEMINFO 2 #define ARM_SMCCC_KVM_FUNC_MEM_SHARE 3 #define ARM_SMCCC_KVM_FUNC_MEM_UNSHARE 4 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_5 5 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_6 6 #define ARM_SMCCC_KVM_FUNC_MMIO_GUARD 7 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_8 8 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_9 9 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_10 10 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_11 11 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_12 12 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_13 13 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_14 14 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_15 15 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_16 16 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_17 17 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_18 18 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_19 19 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_20 20 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_21 21 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_22 22 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_23 23 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_24 24 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_25 25 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_26 26 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_27 27 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_28 28 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_29 29 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_30 30 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_31 31 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_32 32 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_33 33 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_34 34 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_35 35 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_36 36 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_37 37 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_38 38 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_39 39 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_40 40 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_41 41 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_42 42 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_43 43 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_44 44 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_45 45 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_46 46 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_47 47 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_48 48 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_49 49 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_50 50 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_51 51 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_52 52 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_53 53 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_54 54 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_55 55 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_56 56 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_57 57 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_58 58 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_59 59 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_60 60 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_61 61 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_62 62 +#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_63 63 +/* End of pKVM hypercall range */ #define ARM_SMCCC_KVM_FUNC_FEATURES_2 127 #define ARM_SMCCC_KVM_NUM_FUNCS 128