KVM: selftests: Enable ucall and dirty_log_test on s390x

The way we exit from a guest to userspace is very specific to the
architecture: On x86, we use PIO, on aarch64 we are using MMIO and on s390x we're going to use an instruction instead. The possibility to select a type via the ucall_type_t enum is currently also completely unused, so the code in ucall.c currently looks more complex than required. Let's split this up into architecture specific ucall.c files instead, so we can get rid of the #ifdefs and the unnecessary ucall_type_t handling.

Signed-off-by Thomas Huth <[email protected]>

---
 tools/testing/selftests/kvm/Makefile          |   6 +-
 tools/testing/selftests/kvm/dirty_log_test.c  |   2 +-
 .../testing/selftests/kvm/include/kvm_util.h  |   8 +-
 .../testing/selftests/kvm/lib/aarch64/ucall.c | 112 +++++++++++++
 tools/testing/selftests/kvm/lib/ucall.c       | 157 ------------------
 .../testing/selftests/kvm/lib/x86_64/ucall.c  |  56 +++++++
 6 files changed, 173 insertions(+), 168 deletions(-)
 create mode 100644 tools/testing/selftests/kvm/lib/aarch64/ucall.c
 delete mode 100644 tools/testing/selftests/kvm/lib/ucall.c
 create mode 100644 tools/testing/selftests/kvm/lib/x86_64/ucall.c

tools/testing/selftests/kvm/Makefile +3 -3

index ba7849751989..a51e3b83df40 100644
@@ -7,9 +7,9 @@ top_srcdir = ../../../..
 KSFT_KHDR_INSTALL := 1
 UNAME_M := $(shell uname -m)
 
-LIBKVM = lib/assert.c lib/elf.c lib/io.c lib/kvm_util.c lib/ucall.c lib/sparsebit.c
-LIBKVM_x86_64 = lib/x86_64/processor.c lib/x86_64/vmx.c
-LIBKVM_aarch64 = lib/aarch64/processor.c
+LIBKVM = lib/assert.c lib/elf.c lib/io.c lib/kvm_util.c lib/sparsebit.c
+LIBKVM_x86_64 = lib/x86_64/processor.c lib/x86_64/vmx.c lib/x86_64/ucall.c
+LIBKVM_aarch64 = lib/aarch64/processor.c lib/aarch64/ucall.c
 LIBKVM_s390x = lib/s390x/processor.c
 
 TEST_GEN_PROGS_x86_64 = x86_64/cr4_cpuid_sync_test

tools/testing/selftests/kvm/dirty_log_test.c +1 -1

index ceb52b952637..5d5ae1be4984 100644
@@ -337,7 +337,7 @@ static void run_test(enum vm_guest_mode mode, unsigned long iterations,
 	vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
 #endif
 #ifdef __aarch64__
-	ucall_init(vm, UCALL_MMIO, NULL);
+	ucall_init(vm, NULL);
 #endif
 
 	/* Export the shared variables to the guest */

tools/testing/selftests/kvm/include/kvm_util.h +1 -7

index e0e66b115ef2..5463b7896a0a 100644
@@ -165,12 +165,6 @@ int vm_create_device(struct kvm_vm *vm, struct kvm_create_device *cd);
 	memcpy(&(g), _p, sizeof(g));				\
 })
 
-/* ucall implementation types */
-typedef enum {
-	UCALL_PIO,
-	UCALL_MMIO,
-} ucall_type_t;
-
 /* Common ucalls */
 enum {
 	UCALL_NONE,

@@ -186,7 +180,7 @@ struct ucall {
 	uint64_t args[UCALL_MAX_ARGS];
 };
 
-void ucall_init(struct kvm_vm *vm, ucall_type_t type, void *arg);
+void ucall_init(struct kvm_vm *vm, void *arg);
 void ucall_uninit(struct kvm_vm *vm);
 void ucall(uint64_t cmd, int nargs, ...);
 uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc);

tools/testing/selftests/kvm/lib/aarch64/ucall.c new file +0 -0

new file mode 100644
index 000000000000..f69f951a48c0

tools/testing/selftests/kvm/lib/aarch64/ucall.c new file +104 -0

+
+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;
+}

tools/testing/selftests/kvm/lib/ucall.c deleted +0 -157

deleted file mode 100644
index dd9a66700f96..000000000000
@@ -1,157 +0,0 @@
-// 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"
-
-#define UCALL_PIO_PORT ((uint16_t)0x1000)
-
-static ucall_type_t ucall_type;
-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, ucall_type_t type, void *arg)
-{
-	ucall_type = type;
-	sync_global_to_guest(vm, ucall_type);
-
-	if (type == UCALL_PIO)
-		return;
-
-	if (type == UCALL_MMIO) {
-		vm_paddr_t gpa, start, end, step, offset;
-		unsigned 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_type = 0;
-	sync_global_to_guest(vm, ucall_type);
-	ucall_exit_mmio_addr = 0;
-	sync_global_to_guest(vm, ucall_exit_mmio_addr);
-}
-
-static void ucall_pio_exit(struct ucall *uc)
-{
-#ifdef __x86_64__
-	asm volatile("in %[port], %%al"
-		: : [port] "d" (UCALL_PIO_PORT), "D" (uc) : "rax");
-#endif
-}
-
-static void ucall_mmio_exit(struct ucall *uc)
-{
-	*ucall_exit_mmio_addr = (vm_vaddr_t)uc;
-}
-
-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);
-
-	switch (ucall_type) {
-	case UCALL_PIO:
-		ucall_pio_exit(&uc);
-		break;
-	case UCALL_MMIO:
-		ucall_mmio_exit(&uc);
-		break;
-	};
-}
-
-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 = {};
-	bool got_ucall = false;
-
-#ifdef __x86_64__
-	if (ucall_type == UCALL_PIO && run->exit_reason == KVM_EXIT_IO &&
-	    run->io.port == UCALL_PIO_PORT) {
-		struct kvm_regs regs;
-		vcpu_regs_get(vm, vcpu_id, &regs);
-		memcpy(&ucall, addr_gva2hva(vm, (vm_vaddr_t)regs.rdi), sizeof(ucall));
-		got_ucall = true;
-	}
-#endif
-	if (ucall_type == UCALL_MMIO && 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));
-		got_ucall = true;
-	}
-
-	if (got_ucall) {
-		vcpu_run_complete_io(vm, vcpu_id);
-		if (uc)
-			memcpy(uc, &ucall, sizeof(ucall));
-	}
-
-	return ucall.cmd;
-}

tools/testing/selftests/kvm/lib/x86_64/ucall.c new file +56 -0

new file mode 100644
index 000000000000..4bfc9a90b1de
@@ -0,0 +1,56 @@
+// 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"
+
+#define UCALL_PIO_PORT ((uint16_t)0x1000)
+
+void ucall_init(struct kvm_vm *vm, void *arg)
+{
+}
+
+void ucall_uninit(struct kvm_vm *vm)
+{
+}
+
+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);
+
+	asm volatile("in %[port], %%al"
+		: : [port] "d" (UCALL_PIO_PORT), "D" (&uc) : "rax");
+}
+
+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_IO && run->io.port == UCALL_PIO_PORT) {
+		struct kvm_regs regs;
+
+		vcpu_regs_get(vm, vcpu_id, &regs);
+		memcpy(&ucall, addr_gva2hva(vm, (vm_vaddr_t)regs.rdi),
+		       sizeof(ucall));
+
+		vcpu_run_complete_io(vm, vcpu_id);
+		if (uc)
+			memcpy(uc, &ucall, sizeof(ucall));
+	}
+
+	return ucall.cmd;
+}

Signature · 1 line

2.21.0

Implement the ucall() interface on s390x to be able to use the dirty_log_test KVM selftest on s390x, too.

v2:
- Split up ucall.c into architecture specific files
- Removed some #ifdef __s390x__ in the dirty_log patch

Thomas Huth (3):
KVM: selftests: Split ucall.c into architecture specific files

Implement the ucall() interface on s390x to be able to use the dirty_log_test KVM selftest on s390x, too.

v2:
- Split up ucall.c into architecture specific files
- Removed some #ifdef __s390x__ in the dirty_log patch

Thomas Huth (3):
KVM: selftests: Split ucall.c into architecture specific files
KVM: selftests: Implement ucall() for s390x
KVM: selftests: Enable dirty_log_test on s390x

 tools/testing/selftests/kvm/Makefile          |   9 +-
 tools/testing/selftests/kvm/dirty_log_test.c  |  61 ++++++-
 .../testing/selftests/kvm/include/kvm_util.h  |   8 +-
 .../testing/selftests/kvm/lib/aarch64/ucall.c | 112 +++++++++++++
 tools/testing/selftests/kvm/lib/s390x/ucall.c |  56 +++++++
 tools/testing/selftests/kvm/lib/ucall.c       | 157 ------------------
 .../testing/selftests/kvm/lib/x86_64/ucall.c  |  56 +++++++
 .../selftests/kvm/s390x/sync_regs_test.c      |   6 +-
 8 files changed, 287 insertions(+), 178 deletions(-)
 create mode 100644 tools/testing/selftests/kvm/lib/aarch64/ucall.c
 create mode 100644 tools/testing/selftests/kvm/lib/s390x/ucall.c
 delete mode 100644 tools/testing/selftests/kvm/lib/ucall.c
 create mode 100644 tools/testing/selftests/kvm/lib/x86_64/ucall.c

Signature · 1 line

2.21.0