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

[Christian Borntraeger <borntraeger@linux.ibm.com>]

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)