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

Christian Borntraeger
2024-09-18T10:46:06Z

Am 17.09.24 um 17:18 schrieb Nico Boehr:
> 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>
Reviewed-by: Christian Borntraeger <borntraeger@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)