From 0304f75f61dfc1838904e9efc77646f0032b7467 Mon Sep 17 00:00:00 2001 From: Viktor Mihajlovski Date: Thu, 5 Apr 2018 17:07:24 +0200 Subject: [PATCH] s390: Do not pass inofficial IPL type to the guest IPL over a virtio-scsi device requires special handling not available in the real architecture. For this purpose the IPL type 0xFF has been chosen as means of communication between QEMU and the pc-bios. However, a guest OS could be confused by seeing an unknown IPL type. This change sets the IPL parameter type to 0x02 (CCW) to prevent this. Pre-existing Linux has looked up the IPL parameters only in the case of FCP IPL. This means that the behavior should stay the same even if Linux checks for the IPL type unconditionally. Signed-off-by: Viktor Mihajlovski Message-Id: <1522940844-12336-4-git-send-email-mihajlov@linux.vnet.ibm.com> Reviewed-by: Christian Borntraeger Signed-off-by: Cornelia Huck (cherry picked from commit e8c7ef288abb05b741a95418ee2de85c1071e0db) Signed-off-by: Michael Roth --- pc-bios/s390-ccw/bootmap.c | 7 +++++++ pc-bios/s390-ccw/iplb.h | 15 +++++++++++++-- 2 files changed, 20 insertions(+), 2 deletions(-) diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c index 67a6123ed4e..bc01bbccbe6 100644 --- a/pc-bios/s390-ccw/bootmap.c +++ b/pc-bios/s390-ccw/bootmap.c @@ -50,6 +50,13 @@ static void jump_to_IPL_code(uint64_t address) { /* store the subsystem information _after_ the bootmap was loaded */ write_subsystem_identification(); + + /* prevent unknown IPL types in the guest */ + if (iplb.pbt == S390_IPL_TYPE_QEMU_SCSI) { + iplb.pbt = S390_IPL_TYPE_CCW; + set_iplb(&iplb); + } + /* * The IPL PSW is at address 0. We also must not overwrite the * content of non-BIOS memory after we loaded the guest, so we diff --git a/pc-bios/s390-ccw/iplb.h b/pc-bios/s390-ccw/iplb.h index 890aed9ecee..40fc2d8e215 100644 --- a/pc-bios/s390-ccw/iplb.h +++ b/pc-bios/s390-ccw/iplb.h @@ -77,16 +77,27 @@ extern IplParameterBlock iplb __attribute__((__aligned__(PAGE_SIZE))); #define S390_IPL_TYPE_CCW 0x02 #define S390_IPL_TYPE_QEMU_SCSI 0xff -static inline bool store_iplb(IplParameterBlock *iplb) +static inline bool manage_iplb(IplParameterBlock *iplb, bool store) { register unsigned long addr asm("0") = (unsigned long) iplb; register unsigned long rc asm("1") = 0; asm volatile ("diag %0,%2,0x308\n" : "+d" (addr), "+d" (rc) - : "d" (6) + : "d" (store ? 6 : 5) : "memory", "cc"); return rc == 0x01; } + +static inline bool store_iplb(IplParameterBlock *iplb) +{ + return manage_iplb(iplb, true); +} + +static inline bool set_iplb(IplParameterBlock *iplb) +{ + return manage_iplb(iplb, false); +} + #endif /* IPLB_H */ -- 2.39.5