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Wed, 3 Jun 2026 15:47:58 +0000 (GMT) From: Claudio Imbrenda To: linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, borntraeger@de.ibm.com, frankja@linux.ibm.com, david@kernel.org, seiden@linux.ibm.com, nrb@linux.ibm.com, schlameuss@linux.ibm.com, gra@linux.ibm.com Subject: [PATCH v1 1/3] KVM: s390: Add module parameter to fence 2G hugepages Date: Wed, 3 Jun 2026 17:47:56 +0200 Message-ID: <20260603154758.234768-2-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260603154758.234768-1-imbrenda@linux.ibm.com> References: <20260603154758.234768-1-imbrenda@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: o_yKTI8r78Slz98IBj2HnNmwbVTkTM3B X-Authority-Analysis: v=2.4 cv=fv/sol4f c=1 sm=1 tr=0 ts=6a204cb6 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VnNF1IyMAAAA:8 a=-5nL1enD9Bub2BjMfYYA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjAzMDE1MSBTYWx0ZWRfX2TJtDFuh/roT 6k2Lv1269D+FnADCh9EPnPEpd9vj5kRG1Z5z7XWzHVn2viF3xljh9BDNiqFYL/8s18Z9zBPVhSK Ty9sfJFEY1QlJ7/iAVvrK9l65WUxhe6B9nkLc2fRUk1u7eTUVYyD6YejGQskyYufQpOTGpcHjRM YQ+GvvkDUWLAS5mahUiYvgWWhymDmyWCiFx677Y9Wtu9WTytjETpKdINJlVSug/85fITltPZU3/ qcbkmOMsBgOt8j9M+4fNdtE7n08jLC2SFeEuHG7v/YNuF6OPpcGcCORdlZMYYKiGucv8v7B7krQ nmM3p1dHPQVRy7x/Ibva5++gKXY0fT+4E/1OzCEEU84Kpxc9pPNlrfjqx0OSCi1ZXp0H8dugoI/ 302YzFervVVuf+EUOhn/t59LoRLBFkogY+QDy51Yj6bShPgcETU+EuPbORobQxBLxJgBkiiLf3o oN6fU/RlwcCnDdorLHw== X-Proofpoint-ORIG-GUID: o_yKTI8r78Slz98IBj2HnNmwbVTkTM3B X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-03_05,2026-05-28_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 priorityscore=1501 spamscore=0 phishscore=0 clxscore=1015 impostorscore=0 suspectscore=0 bulkscore=0 lowpriorityscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2605210000 definitions=main-2606030151 Add the hpage_2g module parameter to KVM to allow enabling or disabling 2G hugepages in KVM. If hpage_2g is enabled but hpage is not enabled, print a message and disable hpage_2g. Opportunistically fix the comment for the hpage module parameter. Signed-off-by: Claudio Imbrenda --- arch/s390/kvm/kvm-s390.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index ffb20a64d328..801a622691b6 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -204,11 +204,16 @@ static int nested; module_param(nested, int, S_IRUGO); MODULE_PARM_DESC(nested, "Nested virtualization support"); -/* allow 1m huge page guest backing, if !nested */ +/* allow 1m huge page guest backing */ static int hpage; module_param(hpage, int, 0444); MODULE_PARM_DESC(hpage, "1m huge page backing support"); +/* allow 2g huge page guest backing */ +static int hpage_2g; +module_param(hpage_2g, int, 0444); +MODULE_PARM_DESC(hpage_2g, "2g huge page backing support"); + /* maximum percentage of steal time for polling. >100 is treated like 100 */ static u8 halt_poll_max_steal = 10; module_param(halt_poll_max_steal, byte, 0644); @@ -5820,6 +5825,11 @@ static int __init kvm_s390_init(void) return -ENODEV; } + if (hpage_2g && !hpage) { + hpage_2g = 0; + pr_info("Disabling 2G hugepage support, since 1M hugepage support is not enabled.\n"); + } + for (i = 0; i < 16; i++) kvm_s390_fac_base[i] |= stfle_fac_list[i] & nonhyp_mask(i); -- 2.54.0