| Message ID | 20241016180320.686132-5-nsg@linux.ibm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | s390x: STFLE nested interpretation | expand |
On 10/16/24 8:03 PM, Nina Schoetterl-Glausch wrote: > 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@linux.ibm.com> > --- > s390x/Makefile | 4 ++- > lib/s390x/asm/arch_def.h | 13 +++++++++ > lib/s390x/snippet-exit.h | 47 +++++++++++++++++++++++++++++++ > s390x/snippets/lib/snippet-exit.h | 28 ++++++++++++++++++ > 4 files changed, 91 insertions(+), 1 deletion(-) > 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 0ad8d021..1caf221d 100644 > --- a/s390x/Makefile > +++ b/s390x/Makefile > @@ -70,7 +70,8 @@ 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)) > @@ -151,6 +152,7 @@ endif > $(SNIPPET_DIR)/asm/%.o: $(SNIPPET_DIR)/asm/%.S $(asm-offsets) > $(CC) $(CFLAGS) -c -nostdlib -o $@ $< > > +$(SNIPPET_DIR)/c/%.o: SNIPPET_INCLUDE := $(SNIPPET_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 745a3387..db04deca 100644 > --- a/lib/s390x/asm/arch_def.h > +++ b/lib/s390x/asm/arch_def.h > @@ -504,4 +504,17 @@ 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 diag9c(uint64_t val) > +{ > + asm volatile("diag %[val],0,0x9c\n" > + : > + : [val] "d"(val) > + ); > +} > + > #endif > diff --git a/lib/s390x/snippet-exit.h b/lib/s390x/snippet-exit.h > new file mode 100644 > index 00000000..f62f0068 > --- /dev/null > +++ b/lib/s390x/snippet-exit.h > @@ -0,0 +1,47 @@ > +/* 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, 0x9c); > +} > + > +static inline uint64_t snippet_get_force_exit_value(struct vm *vm) > +{ > + struct kvm_s390_sie_block *sblk = vm->sblk; > + > + assert(snippet_is_force_exit_value(vm)); > + > + return vm->save_area.guest.grs[sblk_ip_as_diag(sblk).r_1]; > +} The cpu address parameter for 9C is 16 bit. While we could make it 64 bit for snippets I don't see a reason to do so. The 16 bits are enough to indicate something to the host which can then go and fetch memory for more data.
diff --git a/s390x/Makefile b/s390x/Makefile index 0ad8d021..1caf221d 100644 --- a/s390x/Makefile +++ b/s390x/Makefile @@ -70,7 +70,8 @@ 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)) @@ -151,6 +152,7 @@ endif $(SNIPPET_DIR)/asm/%.o: $(SNIPPET_DIR)/asm/%.S $(asm-offsets) $(CC) $(CFLAGS) -c -nostdlib -o $@ $< +$(SNIPPET_DIR)/c/%.o: SNIPPET_INCLUDE := $(SNIPPET_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 745a3387..db04deca 100644 --- a/lib/s390x/asm/arch_def.h +++ b/lib/s390x/asm/arch_def.h @@ -504,4 +504,17 @@ 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 diag9c(uint64_t val) +{ + asm volatile("diag %[val],0,0x9c\n" + : + : [val] "d"(val) + ); +} + #endif diff --git a/lib/s390x/snippet-exit.h b/lib/s390x/snippet-exit.h new file mode 100644 index 00000000..f62f0068 --- /dev/null +++ b/lib/s390x/snippet-exit.h @@ -0,0 +1,47 @@ +/* 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, 0x9c); +} + +static inline uint64_t snippet_get_force_exit_value(struct vm *vm) +{ + struct kvm_s390_sie_block *sblk = vm->sblk; + + assert(snippet_is_force_exit_value(vm)); + + return vm->save_area.guest.grs[sblk_ip_as_diag(sblk).r_1]; +} + +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..0b483366 --- /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 */ + diag9c(val); + mb(); /* allow host to modify guest memory */ +} + +#endif /* _S390X_SNIPPET_LIB_EXIT_H_ */
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@linux.ibm.com> --- s390x/Makefile | 4 ++- lib/s390x/asm/arch_def.h | 13 +++++++++ lib/s390x/snippet-exit.h | 47 +++++++++++++++++++++++++++++++ s390x/snippets/lib/snippet-exit.h | 28 ++++++++++++++++++ 4 files changed, 91 insertions(+), 1 deletion(-) create mode 100644 lib/s390x/snippet-exit.h create mode 100644 s390x/snippets/lib/snippet-exit.h