103 lines
2.3 KiB
C
103 lines
2.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
|
|
/*
|
|
* Implementation of the memory encryption/decryption API.
|
|
*
|
|
* Amusingly, no crypto is actually performed. Rather, we call into the
|
|
* hypervisor component of KVM to expose pages selectively to the host
|
|
* for virtio "DMA" operations. In other words, "encrypted" pages are
|
|
* not accessible to the host, whereas "decrypted" pages are.
|
|
*
|
|
* Author: Will Deacon <will@kernel.org>
|
|
*/
|
|
#include <linux/arm-smccc.h>
|
|
#include <linux/mem_encrypt.h>
|
|
#include <linux/memory.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/set_memory.h>
|
|
#include <linux/types.h>
|
|
|
|
#include <asm/hypervisor.h>
|
|
|
|
static unsigned long memshare_granule_sz;
|
|
|
|
bool mem_encrypt_active(void)
|
|
{
|
|
return memshare_granule_sz;
|
|
}
|
|
EXPORT_SYMBOL(mem_encrypt_active);
|
|
|
|
void kvm_init_memshare_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) {
|
|
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;
|
|
|
|
memshare_granule_sz = res.a0;
|
|
}
|
|
|
|
static int arm_smccc_share_unshare_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 += memshare_granule_sz;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int set_memory_xcrypted(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_share_unshare_page(func_id, virt_to_phys(addr));
|
|
if (err)
|
|
return err;
|
|
|
|
addr += PAGE_SIZE;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int set_memory_encrypted(unsigned long addr, int numpages)
|
|
{
|
|
if (!memshare_granule_sz || WARN_ON(!PAGE_ALIGNED(addr)))
|
|
return 0;
|
|
|
|
return set_memory_xcrypted(ARM_SMCCC_VENDOR_HYP_KVM_MEM_UNSHARE_FUNC_ID,
|
|
addr, numpages);
|
|
}
|
|
|
|
int set_memory_decrypted(unsigned long addr, int numpages)
|
|
{
|
|
if (!memshare_granule_sz || WARN_ON(!PAGE_ALIGNED(addr)))
|
|
return 0;
|
|
|
|
return set_memory_xcrypted(ARM_SMCCC_VENDOR_HYP_KVM_MEM_SHARE_FUNC_ID,
|
|
addr, numpages);
|
|
}
|