diff options
| author | Janosch Frank <frankja@linux.ibm.com> | 2020-09-08 09:05:04 -0400 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2020-09-14 10:08:07 +0200 |
| commit | cd4d3d5f21ddbfae3f686ac0ff405f21f7847ad3 (patch) | |
| tree | a3b50dec29b84d42598df46b2f1ab7981ff2175a | |
| parent | 73ac74c7d489756d2313219a108809921dbfaea1 (diff) | |
s390: add 3f program exception handler
Program exception 3f (secure storage violation) can only be detected
when the CPU is running in SIE with a format 4 state description,
e.g. running a protected guest. Because of this and because user
space partly controls the guest memory mapping and can trigger this
exception, we want to send a SIGSEGV to the process running the guest
and not panic the kernel.
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Cc: <stable@vger.kernel.org> # 5.7
Fixes: 084ea4d611a3 ("s390/mm: add (non)secure page access exceptions handlers")
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
| -rw-r--r-- | arch/s390/kernel/entry.h | 1 | ||||
| -rw-r--r-- | arch/s390/kernel/pgm_check.S | 2 | ||||
| -rw-r--r-- | arch/s390/mm/fault.c | 20 |
3 files changed, 22 insertions, 1 deletions
diff --git a/arch/s390/kernel/entry.h b/arch/s390/kernel/entry.h index faca269d5f27..a44ddc2f2dec 100644 --- a/arch/s390/kernel/entry.h +++ b/arch/s390/kernel/entry.h @@ -26,6 +26,7 @@ void do_protection_exception(struct pt_regs *regs); void do_dat_exception(struct pt_regs *regs); void do_secure_storage_access(struct pt_regs *regs); void do_non_secure_storage_access(struct pt_regs *regs); +void do_secure_storage_violation(struct pt_regs *regs); void addressing_exception(struct pt_regs *regs); void data_exception(struct pt_regs *regs); diff --git a/arch/s390/kernel/pgm_check.S b/arch/s390/kernel/pgm_check.S index 2c27907a5ffc..9a92638360ee 100644 --- a/arch/s390/kernel/pgm_check.S +++ b/arch/s390/kernel/pgm_check.S @@ -80,7 +80,7 @@ PGM_CHECK(do_dat_exception) /* 3b */ PGM_CHECK_DEFAULT /* 3c */ PGM_CHECK(do_secure_storage_access) /* 3d */ PGM_CHECK(do_non_secure_storage_access) /* 3e */ -PGM_CHECK_DEFAULT /* 3f */ +PGM_CHECK(do_secure_storage_violation) /* 3f */ PGM_CHECK(monitor_event_exception) /* 40 */ PGM_CHECK_DEFAULT /* 41 */ PGM_CHECK_DEFAULT /* 42 */ diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index 4c8c063bce5b..996884dcc9fd 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -859,6 +859,21 @@ void do_non_secure_storage_access(struct pt_regs *regs) } NOKPROBE_SYMBOL(do_non_secure_storage_access); +void do_secure_storage_violation(struct pt_regs *regs) +{ + /* + * Either KVM messed up the secure guest mapping or the same + * page is mapped into multiple secure guests. + * + * This exception is only triggered when a guest 2 is running + * and can therefore never occur in kernel context. + */ + printk_ratelimited(KERN_WARNING + "Secure storage violation in task: %s, pid %d\n", + current->comm, current->pid); + send_sig(SIGSEGV, current, 0); +} + #else void do_secure_storage_access(struct pt_regs *regs) { @@ -869,4 +884,9 @@ void do_non_secure_storage_access(struct pt_regs *regs) { default_trap_handler(regs); } + +void do_secure_storage_violation(struct pt_regs *regs) +{ + default_trap_handler(regs); +} #endif |