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Diffstat (limited to 'tools/testing/selftests/kvm/lib/aarch64/ucall.c')
-rw-r--r--tools/testing/selftests/kvm/lib/aarch64/ucall.c112
1 files changed, 112 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 000000000000..6cd91970fbad
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/aarch64/ucall.c
@@ -0,0 +1,112 @@
+// 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_ASSERT(false, "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 = {
+ .cmd = cmd,
+ };
+ va_list va;
+ int i;
+
+ nargs = nargs <= UCALL_MAX_ARGS ? nargs : UCALL_MAX_ARGS;
+
+ va_start(va, nargs);
+ for (i = 0; i < nargs; ++i)
+ uc.args[i] = va_arg(va, uint64_t);
+ va_end(va);
+
+ *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 (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;
+}