Commit 86044c8c authored Feb 26, 2015 by Christian Borntraeger

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>

parent ed6f76b4

arch/s390/kvm/kvm-s390.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -778,15 +778,18 @@ long kvm_arch_vm_ioctl(struct file *filp,
		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"
		);

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