[PATCH 5.4 244/355] KVM: s390: Fix handle_sske page fault handling

[Greg Kroah-Hartman]

From: Janis Schoetterl-Glausch <scgl@xxxxxxxxxxxxx>

[ Upstream commit 85f517b29418158d3e6e90c3f0fc01b306d2f1a1 ]

If handle_sske cannot set the storage key, because there is no
page table entry or no present large page entry, it calls
fixup_user_fault.
However, currently, if the call succeeds, handle_sske returns
-EAGAIN, without having set the storage key.
Instead, retry by continue'ing the loop without incrementing the
address.
The same issue in handle_pfmf was fixed by
a11bdb1a6b78 ("KVM: s390: Fix pfmf and conditional skey emulation").

Fixes: bd096f644319 ("KVM: s390: Add skey emulation fault handling")
Signed-off-by: Janis Schoetterl-Glausch <scgl@xxxxxxxxxxxxx>
Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Reviewed-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20211022152648.26536-1-scgl@xxxxxxxxxxxxx
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 arch/s390/kvm/priv.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 560310e29e275..fa69610fe6b12 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -398,6 +398,8 @@ static int handle_sske(struct kvm_vcpu *vcpu)
 		up_read(&current->mm->mmap_sem);
 		if (rc == -EFAULT)
 			return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+		if (rc == -EAGAIN)
+			continue;
 		if (rc < 0)
 			return rc;
 		start += PAGE_SIZE;
-- 
2.33.0