From: Nina Schoetterl-Glausch <nsg@xxxxxxxxxxxxx> It is useful to be able to force an exit to the host from the snippet, as well as do so while returning a value. Add this functionality, also add helper functions for the host to check for an exit and get or check the value. Use diag 0x44 and 0x9c for this. Add a guest specific snippet header file and rename snippet.h to reflect that it is host specific. Signed-off-by: Nina Schoetterl-Glausch <nsg@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20241016180320.686132-5-nsg@xxxxxxxxxxxxx [ nrb: fix out-of-tree builds ] Signed-off-by: Nico Boehr <nrb@xxxxxxxxxxxxx> --- s390x/Makefile | 7 +++-- lib/s390x/asm/arch_def.h | 16 +++++++++++ lib/s390x/snippet-exit.h | 45 +++++++++++++++++++++++++++++++ s390x/snippets/lib/snippet-exit.h | 28 +++++++++++++++++++ 4 files changed, 94 insertions(+), 2 deletions(-) create mode 100644 lib/s390x/snippet-exit.h create mode 100644 s390x/snippets/lib/snippet-exit.h diff --git a/s390x/Makefile b/s390x/Makefile index 907b3a04..9eeff198 100644 --- a/s390x/Makefile +++ b/s390x/Makefile @@ -71,7 +71,8 @@ test_cases: $(tests) test_cases_binary: $(tests_binary) test_cases_pv: $(tests_pv_binary) -INCLUDE_PATHS = $(SRCDIR)/lib $(SRCDIR)/lib/s390x $(SRCDIR)/s390x +SNIPPET_INCLUDE := +INCLUDE_PATHS = $(SNIPPET_INCLUDE) $(SRCDIR)/lib $(SRCDIR)/lib/s390x $(SRCDIR)/s390x # Include generated header files (e.g. in case of out-of-source builds) INCLUDE_PATHS += lib CPPFLAGS = $(addprefix -I,$(INCLUDE_PATHS)) @@ -122,6 +123,7 @@ asmlib = $(TEST_DIR)/cstart64.o $(TEST_DIR)/cpu.o FLATLIBS = $(libcflat) SNIPPET_DIR = $(TEST_DIR)/snippets +SNIPPET_SRC_DIR = $(SRCDIR)/s390x/snippets snippet_asmlib = $(SNIPPET_DIR)/c/cstart.o snippet_lib = $(snippet_asmlib) lib/auxinfo.o @@ -149,9 +151,10 @@ snippet-hdr-obj = endif # the asm/c snippets %.o have additional generated files as dependencies -$(SNIPPET_DIR)/asm/%.o: $(SNIPPET_DIR)/asm/%.S $(asm-offsets) +$(SNIPPET_DIR)/asm/%.o: $(SNIPPET_SRC_DIR)/asm/%.S $(asm-offsets) $(CC) $(CFLAGS) -c -nostdlib -o $@ $< +$(SNIPPET_DIR)/c/%.o: SNIPPET_INCLUDE := $(SNIPPET_SRC_DIR)/lib $(SNIPPET_DIR)/c/%.o: $(SNIPPET_DIR)/c/%.c $(asm-offsets) $(CC) $(CFLAGS) -c -nostdlib -o $@ $< diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h index 5574a451..03adcd3c 100644 --- a/lib/s390x/asm/arch_def.h +++ b/lib/s390x/asm/arch_def.h @@ -505,4 +505,20 @@ static inline uint32_t get_prefix(void) return current_prefix; } +static inline void diag44(void) +{ + asm volatile("diag 0,0,0x44\n"); +} + +static inline void diag500(uint64_t val) +{ + asm volatile( + "lgr 2,%[val]\n" + "diag 0,0,0x500\n" + : + : [val] "d"(val) + : "r2" + ); +} + #endif diff --git a/lib/s390x/snippet-exit.h b/lib/s390x/snippet-exit.h new file mode 100644 index 00000000..3ed4c22c --- /dev/null +++ b/lib/s390x/snippet-exit.h @@ -0,0 +1,45 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Functionality handling snippet exits + * + * Copyright IBM Corp. 2024 + */ + +#ifndef _S390X_SNIPPET_EXIT_H_ +#define _S390X_SNIPPET_EXIT_H_ + +#include <libcflat.h> +#include <sie.h> +#include <sie-icpt.h> + +static inline bool snippet_is_force_exit(struct vm *vm) +{ + return sie_is_diag_icpt(vm, 0x44); +} + +static inline bool snippet_is_force_exit_value(struct vm *vm) +{ + return sie_is_diag_icpt(vm, 0x500); +} + +static inline uint64_t snippet_get_force_exit_value(struct vm *vm) +{ + assert(snippet_is_force_exit_value(vm)); + + return vm->save_area.guest.grs[2]; +} + +static inline void snippet_check_force_exit_value(struct vm *vm, uint64_t value_exp) +{ + uint64_t value; + + if (snippet_is_force_exit_value(vm)) { + value = snippet_get_force_exit_value(vm); + report(value == value_exp, "guest forced exit with value (0x%lx == 0x%lx)", + value, value_exp); + } else { + report_fail("guest forced exit with value"); + } +} + +#endif /* _S390X_SNIPPET_EXIT_H_ */ diff --git a/s390x/snippets/lib/snippet-exit.h b/s390x/snippets/lib/snippet-exit.h new file mode 100644 index 00000000..ac00de3f --- /dev/null +++ b/s390x/snippets/lib/snippet-exit.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Functionality for exiting the snippet. + * + * Copyright IBM Corp. 2023 + */ + +#ifndef _S390X_SNIPPET_LIB_EXIT_H_ +#define _S390X_SNIPPET_LIB_EXIT_H_ + +#include <asm/arch_def.h> +#include <asm/barrier.h> + +static inline void force_exit(void) +{ + mb(); /* host may read any memory written by the guest before */ + diag44(); + mb(); /* allow host to modify guest memory */ +} + +static inline void force_exit_value(uint64_t val) +{ + mb(); /* host may read any memory written by the guest before */ + diag500(val); + mb(); /* allow host to modify guest memory */ +} + +#endif /* _S390X_SNIPPET_LIB_EXIT_H_ */ -- 2.47.1