1 files changed, 103 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/lib/ucall_common.c b/tools/testing/selftests/kvm/lib/ucall_common.c
new file mode 100644
index 000000000000..0cc0971ce60e
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/ucall_common.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include "kvm_util.h"
+#include "linux/types.h"
+#include "linux/bitmap.h"
+#include "linux/atomic.h"
+
+struct ucall_header {
+	DECLARE_BITMAP(in_use, KVM_MAX_VCPUS);
+	struct ucall ucalls[KVM_MAX_VCPUS];
+};
+
+/*
+ * ucall_pool holds per-VM values (global data is duplicated by each VM), it
+ * must not be accessed from host code.
+ */
+static struct ucall_header *ucall_pool;
+
+void ucall_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa)
+{
+	struct ucall_header *hdr;
+	struct ucall *uc;
+	vm_vaddr_t vaddr;
+	int i;
+
+	vaddr = __vm_vaddr_alloc(vm, sizeof(*hdr), KVM_UTIL_MIN_VADDR, MEM_REGION_DATA);
+	hdr = (struct ucall_header *)addr_gva2hva(vm, vaddr);
+	memset(hdr, 0, sizeof(*hdr));
+
+	for (i = 0; i < KVM_MAX_VCPUS; ++i) {
+		uc = &hdr->ucalls[i];
+		uc->hva = uc;
+	}
+
+	write_guest_global(vm, ucall_pool, (struct ucall_header *)vaddr);
+
+	ucall_arch_init(vm, mmio_gpa);
+}
+
+static struct ucall *ucall_alloc(void)
+{
+	struct ucall *uc;
+	int i;
+
+	GUEST_ASSERT(ucall_pool);
+
+	for (i = 0; i < KVM_MAX_VCPUS; ++i) {
+		if (!test_and_set_bit(i, ucall_pool->in_use)) {
+			uc = &ucall_pool->ucalls[i];
+			memset(uc->args, 0, sizeof(uc->args));
+			return uc;
+		}
+	}
+
+	GUEST_ASSERT(0);
+	return NULL;
+}
+
+static void ucall_free(struct ucall *uc)
+{
+	/* Beware, here be pointer arithmetic.  */
+	clear_bit(uc - ucall_pool->ucalls, ucall_pool->in_use);
+}
+
+void ucall(uint64_t cmd, int nargs, ...)
+{
+	struct ucall *uc;
+	va_list va;
+	int i;
+
+	uc = ucall_alloc();
+
+	WRITE_ONCE(uc->cmd, cmd);
+
+	nargs = min(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);
+
+	ucall_arch_do_ucall((vm_vaddr_t)uc->hva);
+
+	ucall_free(uc);
+}
+
+uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
+{
+	struct ucall ucall;
+	void *addr;
+
+	if (!uc)
+		uc = &ucall;
+
+	addr = ucall_arch_get_ucall(vcpu);
+	if (addr) {
+		memcpy(uc, addr, sizeof(*uc));
+		vcpu_run_complete_io(vcpu);
+	} else {
+		memset(uc, 0, sizeof(*uc));
+	}
+
+	return uc->cmd;
+}