On 03.11.23 18:30, Nina Schoetterl-Glausch wrote:
The length of the facility list accessed when interpretively executing
STFLE is the same as the hosts facility list (in case of format-0)
When shadowing, copy only those bytes.
The memory following the facility list need not be accessible, in which
case we'd wrongly inject a validity intercept.
Fixes: 66b630d5b7f2 ("KVM: s390: vsie: support STFLE interpretation")
Signed-off-by: Nina Schoetterl-Glausch <nsg@xxxxxxxxxxxxx>
---
arch/s390/include/asm/facility.h | 6 ++++++
arch/s390/kernel/Makefile | 2 +-
arch/s390/kernel/facility.c | 18 ++++++++++++++++++
arch/s390/kvm/vsie.c | 12 +++++++++++-
4 files changed, 36 insertions(+), 2 deletions(-)
create mode 100644 arch/s390/kernel/facility.c
diff --git a/arch/s390/include/asm/facility.h b/arch/s390/include/asm/facility.h
index 94b6919026df..796007125dff 100644
--- a/arch/s390/include/asm/facility.h
+++ b/arch/s390/include/asm/facility.h
@@ -111,4 +111,10 @@ static inline void stfle(u64 *stfle_fac_list, int size)
preempt_enable();
}
+/**
+ * stfle_size - Actual size of the facility list as specified by stfle
+ * (number of double words)
+ */
+unsigned int stfle_size(void);
+
#endif /* __ASM_FACILITY_H */
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index 0df2b88cc0da..0daa81439478 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -41,7 +41,7 @@ obj-y += sysinfo.o lgr.o os_info.o
obj-y += runtime_instr.o cache.o fpu.o dumpstack.o guarded_storage.o sthyi.o
obj-y += entry.o reipl.o kdebugfs.o alternative.o
obj-y += nospec-branch.o ipl_vmparm.o machine_kexec_reloc.o unwind_bc.o
-obj-y += smp.o text_amode31.o stacktrace.o abs_lowcore.o
+obj-y += smp.o text_amode31.o stacktrace.o abs_lowcore.o facility.o
extra-y += vmlinux.lds
diff --git a/arch/s390/kernel/facility.c b/arch/s390/kernel/facility.c
new file mode 100644
index 000000000000..c33a95a562da
--- /dev/null
+++ b/arch/s390/kernel/facility.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright IBM Corp. 2023
+ */
+
+#include <asm/facility.h>
+
+unsigned int stfle_size(void)
+{
+ static unsigned int size = 0;
+ u64 dummy;
+
+ if (!size) {
+ size = __stfle_asm(&dummy, 1) + 1;
+ }
+ return size;
+}
+EXPORT_SYMBOL(stfle_size);
Possible races? Should have to use an atomic?
No access to documentation, but sounds plausible.
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
--
Cheers,
David / dhildenb
