From: Heiko Carstens hca@linux.ibm.com
[ Upstream commit 0c02cc576eac161601927b41634f80bfd55bfa9e ]
Commit 9fb6c9b3fea1 ("s390/sthyi: add cache to store hypervisor info") added cache handling for store hypervisor info. This also changed the possible return code for sthyi_fill().
Instead of only returning a condition code like the sthyi instruction would do, it can now also return a negative error value (-ENOMEM). handle_styhi() was not changed accordingly. In case of an error, the negative error value would incorrectly injected into the guest PSW.
Add proper error handling to prevent this, and update the comment which describes the possible return values of sthyi_fill().
Fixes: 9fb6c9b3fea1 ("s390/sthyi: add cache to store hypervisor info") Reviewed-by: Christian Borntraeger borntraeger@linux.ibm.com Link: https://lore.kernel.org/r/20230727182939.2050744-1-hca@linux.ibm.com Signed-off-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/s390/kernel/sthyi.c | 6 +++--- arch/s390/kvm/intercept.c | 9 ++++++--- 2 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/arch/s390/kernel/sthyi.c b/arch/s390/kernel/sthyi.c index 888cc2f166db7..ce6084e28d904 100644 --- a/arch/s390/kernel/sthyi.c +++ b/arch/s390/kernel/sthyi.c @@ -460,9 +460,9 @@ static int sthyi_update_cache(u64 *rc) * * Fills the destination with system information returned by the STHYI * instruction. The data is generated by emulation or execution of STHYI, - * if available. The return value is the condition code that would be - * returned, the rc parameter is the return code which is passed in - * register R2 + 1. + * if available. The return value is either a negative error value or + * the condition code that would be returned, the rc parameter is the + * return code which is passed in register R2 + 1. */ int sthyi_fill(void *dst, u64 *rc) { diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c index 5be68190901f9..8bf72a323e4fa 100644 --- a/arch/s390/kvm/intercept.c +++ b/arch/s390/kvm/intercept.c @@ -387,8 +387,8 @@ static int handle_partial_execution(struct kvm_vcpu *vcpu) */ int handle_sthyi(struct kvm_vcpu *vcpu) { - int reg1, reg2, r = 0; - u64 code, addr, cc = 0, rc = 0; + int reg1, reg2, cc = 0, r = 0; + u64 code, addr, rc = 0; struct sthyi_sctns *sctns = NULL;
if (!test_kvm_facility(vcpu->kvm, 74)) @@ -419,7 +419,10 @@ int handle_sthyi(struct kvm_vcpu *vcpu) return -ENOMEM;
cc = sthyi_fill(sctns, &rc); - + if (cc < 0) { + free_page((unsigned long)sctns); + return cc; + } out: if (!cc) { if (kvm_s390_pv_cpu_is_protected(vcpu)) {