[PATCH v1 2/2] KVM: s390: Change virtual to physical address access in diag 0x258 handler

Nico Boehr
2024-09-17T15:19:45Z

From: Michael Mueller <mimu@linux.ibm.com>

The parameters for the diag 0x258 are real addresses, not virtual, but
KVM was using them as virtual addresses. This only happened to work, since
the Linux kernel as a guest used to have a 1:1 mapping for physical vs
virtual addresses.

Fix KVM so that it correctly uses the addresses as real addresses.

Cc: stable@vger.kernel.org
Fixes: 8ae04b8f500b ("KVM: s390: Guest's memory access functions get access registers")
Suggested-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Michael Mueller <mimu@linux.ibm.com>
[ nrb: drop tested-by tags ]
Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
---
arch/s390/kvm/diag.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c
index 2a32438e09ce..74f73141f9b9 100644
--- a/arch/s390/kvm/diag.c
+++ b/arch/s390/kvm/diag.c
@@ -77,7 +77,7 @@ static int __diag_page_ref_service(struct kvm_vcpu *vcpu)
vcpu->stat.instruction_diagnose_258++;
if (vcpu->run->s.regs.gprs[rx] & 7)
return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
- rc = read_guest(vcpu, vcpu->run->s.regs.gprs[rx], rx, &parm, sizeof(parm));
+ rc = read_guest_real(vcpu, vcpu->run->s.regs.gprs[rx], &parm, sizeof(parm));
if (rc)
return kvm_s390_inject_prog_cond(vcpu, rc);
if (parm.parm_version != 2 || parm.parm_len < 5 || parm.code != 0x258)
--
2.46.0