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Merge branch 'for-next/pkvm-guest' into for-next/core
* for-next/pkvm-guest: arm64: smccc: Reserve block of KVM "vendor" services for pKVM hypercalls drivers/virt: pkvm: Intercept ioremap using pKVM MMIO_GUARD hypercall arm64: mm: Add confidential computing hook to ioremap_prot() drivers/virt: pkvm: Hook up mem_encrypt API using pKVM hypercalls arm64: mm: Add top-level dispatcher for internal mem_encrypt API drivers/virt: pkvm: Add initial support for running as a protected guest firmware/smccc: Call arch-specific hook on discovering KVM services
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‎Documentation/virt/kvm/arm/hypercalls.rst‎

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@@ -44,3 +44,101 @@ Provides a discovery mechanism for other KVM/arm64 hypercalls.
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----------------------------------------
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See ptp_kvm.rst
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``ARM_SMCCC_KVM_FUNC_HYP_MEMINFO``
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----------------------------------
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Query the memory protection parameters for a pKVM protected virtual machine.
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+---------------------+-------------------------------------------------------------+
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| Presence: | Optional; pKVM protected guests only. |
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+---------------------+-------------------------------------------------------------+
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| Calling convention: | HVC64 |
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+---------------------+----------+--------------------------------------------------+
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| Function ID: | (uint32) | 0xC6000002 |
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+---------------------+----------+----+---------------------------------------------+
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| Arguments: | (uint64) | R1 | Reserved / Must be zero |
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| +----------+----+---------------------------------------------+
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| | (uint64) | R2 | Reserved / Must be zero |
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| +----------+----+---------------------------------------------+
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| | (uint64) | R3 | Reserved / Must be zero |
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+---------------------+----------+----+---------------------------------------------+
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| Return Values: | (int64) | R0 | ``INVALID_PARAMETER (-3)`` on error, else |
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| | | | memory protection granule in bytes |
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+---------------------+----------+----+---------------------------------------------+
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``ARM_SMCCC_KVM_FUNC_MEM_SHARE``
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--------------------------------
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Share a region of memory with the KVM host, granting it read, write and execute
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permissions. The size of the region is equal to the memory protection granule
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advertised by ``ARM_SMCCC_KVM_FUNC_HYP_MEMINFO``.
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+---------------------+-------------------------------------------------------------+
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| Presence: | Optional; pKVM protected guests only. |
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+---------------------+-------------------------------------------------------------+
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| Calling convention: | HVC64 |
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+---------------------+----------+--------------------------------------------------+
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| Function ID: | (uint32) | 0xC6000003 |
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+---------------------+----------+----+---------------------------------------------+
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| Arguments: | (uint64) | R1 | Base IPA of memory region to share |
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| +----------+----+---------------------------------------------+
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| | (uint64) | R2 | Reserved / Must be zero |
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| +----------+----+---------------------------------------------+
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| | (uint64) | R3 | Reserved / Must be zero |
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+---------------------+----------+----+---------------------------------------------+
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| Return Values: | (int64) | R0 | ``SUCCESS (0)`` |
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| | | +---------------------------------------------+
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| | | | ``INVALID_PARAMETER (-3)`` |
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+---------------------+----------+----+---------------------------------------------+
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``ARM_SMCCC_KVM_FUNC_MEM_UNSHARE``
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----------------------------------
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Revoke access permission from the KVM host to a memory region previously shared
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with ``ARM_SMCCC_KVM_FUNC_MEM_SHARE``. The size of the region is equal to the
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memory protection granule advertised by ``ARM_SMCCC_KVM_FUNC_HYP_MEMINFO``.
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+---------------------+-------------------------------------------------------------+
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| Presence: | Optional; pKVM protected guests only. |
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+---------------------+-------------------------------------------------------------+
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| Calling convention: | HVC64 |
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+---------------------+----------+--------------------------------------------------+
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| Function ID: | (uint32) | 0xC6000004 |
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+---------------------+----------+----+---------------------------------------------+
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| Arguments: | (uint64) | R1 | Base IPA of memory region to unshare |
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| +----------+----+---------------------------------------------+
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| | (uint64) | R2 | Reserved / Must be zero |
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| +----------+----+---------------------------------------------+
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| | (uint64) | R3 | Reserved / Must be zero |
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+---------------------+----------+----+---------------------------------------------+
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| Return Values: | (int64) | R0 | ``SUCCESS (0)`` |
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| | | +---------------------------------------------+
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| | | | ``INVALID_PARAMETER (-3)`` |
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+---------------------+----------+----+---------------------------------------------+
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``ARM_SMCCC_KVM_FUNC_MMIO_GUARD``
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----------------------------------
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Request that a given memory region is handled as MMIO by the hypervisor,
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allowing accesses to this region to be emulated by the KVM host. The size of the
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region is equal to the memory protection granule advertised by
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``ARM_SMCCC_KVM_FUNC_HYP_MEMINFO``.
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+---------------------+-------------------------------------------------------------+
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| Presence: | Optional; pKVM protected guests only. |
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+---------------------+-------------------------------------------------------------+
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| Calling convention: | HVC64 |
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+---------------------+----------+--------------------------------------------------+
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| Function ID: | (uint32) | 0xC6000007 |
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+---------------------+----------+----+---------------------------------------------+
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| Arguments: | (uint64) | R1 | Base IPA of MMIO memory region |
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| +----------+----+---------------------------------------------+
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| | (uint64) | R2 | Reserved / Must be zero |
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| +----------+----+---------------------------------------------+
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| | (uint64) | R3 | Reserved / Must be zero |
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+---------------------+----------+----+---------------------------------------------+
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| Return Values: | (int64) | R0 | ``SUCCESS (0)`` |
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| | | +---------------------------------------------+
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| | | | ``INVALID_PARAMETER (-3)`` |
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+---------------------+----------+----+---------------------------------------------+

‎arch/arm/include/asm/hypervisor.h‎

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void kvm_init_hyp_services(void);
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bool kvm_arm_hyp_service_available(u32 func_id);
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static inline void kvm_arch_init_hyp_services(void) { };
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#endif

‎arch/arm64/Kconfig‎

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select ARCH_HAS_KERNEL_FPU_SUPPORT if KERNEL_MODE_NEON
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select ARCH_HAS_KEEPINITRD
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select ARCH_HAS_MEMBARRIER_SYNC_CORE
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select ARCH_HAS_MEM_ENCRYPT
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select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
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select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
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select ARCH_HAS_PTE_DEVMAP

‎arch/arm64/include/asm/hypervisor.h‎

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void kvm_init_hyp_services(void);
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bool kvm_arm_hyp_service_available(u32 func_id);
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#ifdef CONFIG_ARM_PKVM_GUEST
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void pkvm_init_hyp_services(void);
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#else
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static inline void pkvm_init_hyp_services(void) { };
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#endif
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static inline void kvm_arch_init_hyp_services(void)
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{
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pkvm_init_hyp_services();
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};
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#endif

‎arch/arm64/include/asm/io.h‎

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@@ -271,6 +271,10 @@ __iowrite64_copy(void __iomem *to, const void *from, size_t count)
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* I/O memory mapping functions.
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*/
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typedef int (*ioremap_prot_hook_t)(phys_addr_t phys_addr, size_t size,
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pgprot_t *prot);
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int arm64_ioremap_prot_hook_register(const ioremap_prot_hook_t hook);
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#define ioremap_prot ioremap_prot
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#define _PAGE_IOREMAP PROT_DEVICE_nGnRE

‎arch/arm64/include/asm/mem_encrypt.h‎

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/* SPDX-License-Identifier: GPL-2.0-only */
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#ifndef __ASM_MEM_ENCRYPT_H
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#define __ASM_MEM_ENCRYPT_H
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struct arm64_mem_crypt_ops {
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int (*encrypt)(unsigned long addr, int numpages);
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int (*decrypt)(unsigned long addr, int numpages);
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};
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int arm64_mem_crypt_ops_register(const struct arm64_mem_crypt_ops *ops);
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int set_memory_encrypted(unsigned long addr, int numpages);
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int set_memory_decrypted(unsigned long addr, int numpages);
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#endif /* __ASM_MEM_ENCRYPT_H */

‎arch/arm64/include/asm/set_memory.h‎

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#ifndef _ASM_ARM64_SET_MEMORY_H
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#define _ASM_ARM64_SET_MEMORY_H
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#include <asm/mem_encrypt.h>
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#include <asm-generic/set_memory.h>
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bool can_set_direct_map(void);

‎arch/arm64/mm/Makefile‎

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# SPDX-License-Identifier: GPL-2.0
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obj-y := dma-mapping.o extable.o fault.o init.o \
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cache.o copypage.o flush.o \
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ioremap.o mmap.o pgd.o mmu.o \
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ioremap.o mmap.o pgd.o mem_encrypt.o mmu.o \
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context.o proc.o pageattr.o fixmap.o
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obj-$(CONFIG_ARM64_CONTPTE) += contpte.o
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obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o

‎arch/arm64/mm/ioremap.c‎

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#include <linux/mm.h>
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#include <linux/io.h>
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static ioremap_prot_hook_t ioremap_prot_hook;
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int arm64_ioremap_prot_hook_register(ioremap_prot_hook_t hook)
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{
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if (WARN_ON(ioremap_prot_hook))
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return -EBUSY;
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ioremap_prot_hook = hook;
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return 0;
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}
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void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
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unsigned long prot)
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{
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unsigned long last_addr = phys_addr + size - 1;
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pgprot_t pgprot = __pgprot(prot);
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/* Don't allow outside PHYS_MASK */
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if (last_addr & ~PHYS_MASK)
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if (WARN_ON(pfn_is_map_memory(__phys_to_pfn(phys_addr))))
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return NULL;
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return generic_ioremap_prot(phys_addr, size, __pgprot(prot));
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/*
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* If a hook is registered (e.g. for confidential computing
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* purposes), call that now and barf if it fails.
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*/
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if (unlikely(ioremap_prot_hook) &&
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WARN_ON(ioremap_prot_hook(phys_addr, size, &pgprot))) {
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return NULL;
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}
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return generic_ioremap_prot(phys_addr, size, pgprot);
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}
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EXPORT_SYMBOL(ioremap_prot);
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‎arch/arm64/mm/mem_encrypt.c‎

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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Implementation of the memory encryption/decryption API.
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*
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* Since the low-level details of the operation depend on the
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* Confidential Computing environment (e.g. pKVM, CCA, ...), this just
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* acts as a top-level dispatcher to whatever hooks may have been
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* registered.
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*
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* Author: Will Deacon <[email protected]>
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* Copyright (C) 2024 Google LLC
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*
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* "Hello, boils and ghouls!"
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*/
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#include <linux/bug.h>
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#include <linux/compiler.h>
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#include <linux/err.h>
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#include <linux/mm.h>
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#include <asm/mem_encrypt.h>
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static const struct arm64_mem_crypt_ops *crypt_ops;
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int arm64_mem_crypt_ops_register(const struct arm64_mem_crypt_ops *ops)
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{
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if (WARN_ON(crypt_ops))
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return -EBUSY;
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crypt_ops = ops;
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return 0;
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}
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int set_memory_encrypted(unsigned long addr, int numpages)
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{
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if (likely(!crypt_ops) || WARN_ON(!PAGE_ALIGNED(addr)))
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return 0;
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return crypt_ops->encrypt(addr, numpages);
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}
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EXPORT_SYMBOL_GPL(set_memory_encrypted);
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int set_memory_decrypted(unsigned long addr, int numpages)
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{
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if (likely(!crypt_ops) || WARN_ON(!PAGE_ALIGNED(addr)))
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return 0;
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return crypt_ops->decrypt(addr, numpages);
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}
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EXPORT_SYMBOL_GPL(set_memory_decrypted);

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