KVM: s390/cpacf: Fix kernel bug under z/VM
Under z/VM PQAP might trigger an operation exception if no crypto cards
are defined via APVIRTUAL or APDEDICATED.
[ 386.098666] Kernel BUG at 0000000000135c56 [verbose debug info unavailable]
[ 386.098693] illegal operation: 0001 ilc:2 [#1] SMP
[...]
[ 386.098751] Krnl PSW : 0704c00180000000 0000000000135c56 (kvm_s390_apxa_installed+0x46/0x98)
[...]
[ 386.098804] [<000000000013627c>] kvm_arch_init_vm+0x29c/0x358
[ 386.098806] [<000000000012d008>] kvm_dev_ioctl+0xc0/0x460
[ 386.098809] [<00000000002c639a>] do_vfs_ioctl+0x332/0x508
[ 386.098811] [<00000000002c660e>] SyS_ioctl+0x9e/0xb0
[ 386.098814] [<000000000070476a>] system_call+0xd6/0x258
[ 386.098815] [<000003fffc7400a2>] 0x3fffc7400a2
Lets add an extable entry and provide a zeroed config in that case.
Reported-by: Stefan Zimmermann <stzi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Tested-by: Stefan Zimmermann <stzi@linux.vnet.ibm.com>
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index b4d2030..18965f9 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -778,15 +778,18 @@
static int kvm_s390_query_ap_config(u8 *config)
{
u32 fcn_code = 0x04000000UL;
- u32 cc;
+ u32 cc = 0;
+ memset(config, 0, 128);
asm volatile(
"lgr 0,%1\n"
"lgr 2,%2\n"
".long 0xb2af0000\n" /* PQAP(QCI) */
- "ipm %0\n"
+ "0: ipm %0\n"
"srl %0,28\n"
- : "=r" (cc)
+ "1:\n"
+ EX_TABLE(0b, 1b)
+ : "+r" (cc)
: "r" (fcn_code), "r" (config)
: "cc", "0", "2", "memory"
);