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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /tools/testing/selftests/kvm/lib/aarch64/ucall.c | |
parent | Initial commit. (diff) | |
download | linux-430c2fc249ea5c0536abd21c23382884005c9093.tar.xz linux-430c2fc249ea5c0536abd21c23382884005c9093.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tools/testing/selftests/kvm/lib/aarch64/ucall.c')
-rw-r--r-- | tools/testing/selftests/kvm/lib/aarch64/ucall.c | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/lib/aarch64/ucall.c b/tools/testing/selftests/kvm/lib/aarch64/ucall.c new file mode 100644 index 000000000..f600311fd --- /dev/null +++ b/tools/testing/selftests/kvm/lib/aarch64/ucall.c @@ -0,0 +1,114 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * ucall support. A ucall is a "hypercall to userspace". + * + * Copyright (C) 2018, Red Hat, Inc. + */ +#include "kvm_util.h" +#include "../kvm_util_internal.h" + +static vm_vaddr_t *ucall_exit_mmio_addr; + +static bool ucall_mmio_init(struct kvm_vm *vm, vm_paddr_t gpa) +{ + if (kvm_userspace_memory_region_find(vm, gpa, gpa + 1)) + return false; + + virt_pg_map(vm, gpa, gpa, 0); + + ucall_exit_mmio_addr = (vm_vaddr_t *)gpa; + sync_global_to_guest(vm, ucall_exit_mmio_addr); + + return true; +} + +void ucall_init(struct kvm_vm *vm, void *arg) +{ + vm_paddr_t gpa, start, end, step, offset; + unsigned int bits; + bool ret; + + if (arg) { + gpa = (vm_paddr_t)arg; + ret = ucall_mmio_init(vm, gpa); + TEST_ASSERT(ret, "Can't set ucall mmio address to %lx", gpa); + return; + } + + /* + * Find an address within the allowed physical and virtual address + * spaces, that does _not_ have a KVM memory region associated with + * it. Identity mapping an address like this allows the guest to + * access it, but as KVM doesn't know what to do with it, it + * will assume it's something userspace handles and exit with + * KVM_EXIT_MMIO. Well, at least that's how it works for AArch64. + * Here we start with a guess that the addresses around 5/8th + * of the allowed space are unmapped and then work both down and + * up from there in 1/16th allowed space sized steps. + * + * Note, we need to use VA-bits - 1 when calculating the allowed + * virtual address space for an identity mapping because the upper + * half of the virtual address space is the two's complement of the + * lower and won't match physical addresses. + */ + bits = vm->va_bits - 1; + bits = vm->pa_bits < bits ? vm->pa_bits : bits; + end = 1ul << bits; + start = end * 5 / 8; + step = end / 16; + for (offset = 0; offset < end - start; offset += step) { + if (ucall_mmio_init(vm, start - offset)) + return; + if (ucall_mmio_init(vm, start + offset)) + return; + } + TEST_FAIL("Can't find a ucall mmio address"); +} + +void ucall_uninit(struct kvm_vm *vm) +{ + ucall_exit_mmio_addr = 0; + sync_global_to_guest(vm, ucall_exit_mmio_addr); +} + +void ucall(uint64_t cmd, int nargs, ...) +{ + struct ucall uc = {}; + va_list va; + int i; + + WRITE_ONCE(uc.cmd, cmd); + nargs = nargs <= UCALL_MAX_ARGS ? nargs : UCALL_MAX_ARGS; + + va_start(va, nargs); + for (i = 0; i < nargs; ++i) + WRITE_ONCE(uc.args[i], va_arg(va, uint64_t)); + va_end(va); + + WRITE_ONCE(*ucall_exit_mmio_addr, (vm_vaddr_t)&uc); +} + +uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc) +{ + struct kvm_run *run = vcpu_state(vm, vcpu_id); + struct ucall ucall = {}; + + if (uc) + memset(uc, 0, sizeof(*uc)); + + if (run->exit_reason == KVM_EXIT_MMIO && + run->mmio.phys_addr == (uint64_t)ucall_exit_mmio_addr) { + vm_vaddr_t gva; + + TEST_ASSERT(run->mmio.is_write && run->mmio.len == 8, + "Unexpected ucall exit mmio address access"); + memcpy(&gva, run->mmio.data, sizeof(gva)); + memcpy(&ucall, addr_gva2hva(vm, gva), sizeof(ucall)); + + vcpu_run_complete_io(vm, vcpu_id); + if (uc) + memcpy(uc, &ucall, sizeof(ucall)); + } + + return ucall.cmd; +} |