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| author | Thomas Huth <thuth@linux.vnet.ibm.com> | 2014-03-03 23:34:42 +0100 |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2014-04-29 15:01:52 +0200 |
| commit | f8232c8cf720074c0eb0804202d424a2b7b4ee76 (patch) | |
| tree | ee07bdda3663c68fad9cbeaff76935794f3f0286 | |
| parent | 9a558ee3ccb8afcf43c8d9d4d206ab6de4aa30a2 (diff) | |
| download | linux-f8232c8cf720074c0eb0804202d424a2b7b4ee76.tar.gz linux-f8232c8cf720074c0eb0804202d424a2b7b4ee76.tar.bz2 linux-f8232c8cf720074c0eb0804202d424a2b7b4ee76.zip | |
KVM: s390: Add a function for checking the low-address protection
The s390 architecture has a special protection mechanism that can
be used to prevent write access to the vital data in the low-core
memory area. This patch adds a new helper function that can be used
to check for such write accesses and in case of protection, it also
sets up the exception data accordingly.
Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| -rw-r--r-- | arch/s390/kvm/gaccess.c | 28 | ||||
| -rw-r--r-- | arch/s390/kvm/gaccess.h | 1 |
2 files changed, 29 insertions, 0 deletions
diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c index 691fdb776c90..db608c3f9303 100644 --- a/arch/s390/kvm/gaccess.c +++ b/arch/s390/kvm/gaccess.c @@ -643,3 +643,31 @@ int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, } return rc; } + +/** + * kvm_s390_check_low_addr_protection - check for low-address protection + * @ga: Guest address + * + * Checks whether an address is subject to low-address protection and set + * up vcpu->arch.pgm accordingly if necessary. + * + * Return: 0 if no protection exception, or PGM_PROTECTION if protected. + */ +int kvm_s390_check_low_addr_protection(struct kvm_vcpu *vcpu, unsigned long ga) +{ + struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm; + psw_t *psw = &vcpu->arch.sie_block->gpsw; + struct trans_exc_code_bits *tec_bits; + + if (!is_low_address(ga) || !low_address_protection_enabled(vcpu)) + return 0; + + memset(pgm, 0, sizeof(*pgm)); + tec_bits = (struct trans_exc_code_bits *)&pgm->trans_exc_code; + tec_bits->fsi = FSI_STORE; + tec_bits->as = psw_bits(*psw).as; + tec_bits->addr = ga >> PAGE_SHIFT; + pgm->code = PGM_PROTECTION; + + return pgm->code; +} diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h index 1079c8fc6d0d..68db43e4254f 100644 --- a/arch/s390/kvm/gaccess.h +++ b/arch/s390/kvm/gaccess.h @@ -325,5 +325,6 @@ int read_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data, } int ipte_lock_held(struct kvm_vcpu *vcpu); +int kvm_s390_check_low_addr_protection(struct kvm_vcpu *vcpu, unsigned long ga); #endif /* __KVM_S390_GACCESS_H */ |