From fabdada9357b9cfd980c7744ddce47e34600bbef Mon Sep 17 00:00:00 2001 From: Collin Walling Date: Tue, 15 Sep 2020 15:44:16 -0400 Subject: s390: guest support for diagnose 0x318 DIAGNOSE 0x318 (diag318) is an s390 instruction that allows the storage of diagnostic information that is collected by the firmware in the case of hardware/firmware service events. QEMU handles the instruction by storing the info in the CPU state. A subsequent register sync will communicate the data to the hypervisor. QEMU handles the migration via a VM State Description. This feature depends on the Extended-Length SCCB (els) feature. If els is not present, then a warning will be printed and the SCLP bit that allows the Linux kernel to execute the instruction will not be set. Availability of this instruction is determined by byte 134 (aka fac134) bit 0 of the SCLP Read Info block. This coincidentally expands into the space used for CPU entries, which means VMs running with the diag318 capability may not be able to read information regarding all CPUs unless the guest kernel supports an extended-length SCCB. This feature is not supported in protected virtualization mode. Signed-off-by: Collin Walling Acked-by: Janosch Frank Acked-by: Thomas Huth Acked-by: David Hildenbrand Acked-by: Claudio Imbrenda Message-Id: <20200915194416.107460-9-walling@linux.ibm.com> Signed-off-by: Cornelia Huck --- hw/s390x/sclp.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'hw/s390x') diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c index caf40f41b6..00f1e4648d 100644 --- a/hw/s390x/sclp.c +++ b/hw/s390x/sclp.c @@ -139,6 +139,11 @@ static void read_SCP_info(SCLPDevice *sclp, SCCB *sccb) s390_get_feat_block(S390_FEAT_TYPE_SCLP_CONF_CHAR_EXT, read_info->conf_char_ext); + if (s390_has_feat(S390_FEAT_EXTENDED_LENGTH_SCCB)) { + s390_get_feat_block(S390_FEAT_TYPE_SCLP_FAC134, + &read_info->fac134); + } + read_info->facilities = cpu_to_be64(SCLP_HAS_CPU_INFO | SCLP_HAS_IOA_RECONFIG); -- cgit v1.2.3