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charset="iso-8859-1" X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: MW5PR84MB1713.NAMPRD84.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-Network-Message-Id: 9274bdec-45da-46dd-bcee-08db9f5fc9f4 X-MS-Exchange-CrossTenant-originalarrivaltime: 17 Aug 2023 20:23:16.1538 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 105b2061-b669-4b31-92ac-24d304d195dc X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: UZZ1uG2VlI6SW4KQTxtrsccO2+dVGkKzDtUNvf9Hc6fXcxax9r/P/4G46jDG4r0HX5aJiLwUiNEtpKzdhL8xOA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW5PR84MB1820 X-OriginatorOrg: hpe.com X-Proofpoint-GUID: do5CVNRJrbtejcsh4LTZk_3p80L6JqeN X-Proofpoint-ORIG-GUID: do5CVNRJrbtejcsh4LTZk_3p80L6JqeN Content-Transfer-Encoding: quoted-printable X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-HPE-SCL: -1 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.267,Aquarius:18.0.957,Hydra:6.0.601,FMLib:17.11.176.26 definitions=2023-08-17_16,2023-08-17_02,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 malwarescore=0 clxscore=1015 spamscore=0 phishscore=0 mlxlogscore=901 priorityscore=1501 bulkscore=0 lowpriorityscore=0 mlxscore=0 adultscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2306200000 definitions=main-2308170184 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > 4096 is the current maximum value because of the Hyper-V TLFS. See > > BUILD_BUG_ON in arch/x86/kvm/hyperv.c, commit 79661c3, and Vitaly's > > comment on https://lore.kernel.org/all/87r136shcc.fsf@redhat.com. > > Mostly out of curiosity, do you care about Hyper-V support? If not, at = some > point it'd probably be worth exploring a CONFIG_KVM_HYPERV option to allow > disabling KVM's Hyper-V support at compile time so that we're not bound b= y the > restrictions of the TLFS. Yes, I care about Hyper-V support. I would like this limitation to be addre= ssed in the future. > Rather than tightly couple this to MAXSMP, what if we add a Kconfig? I k= now of > at least one scenario, SVM's AVIC/x2AVIC, where it would be desirable to = configure > KVM to a much smaller maximum. The biggest downside I can think of is th= at KVM > selftests would need to be updated (they assume the max is >=3D512), and = some of the > tests might be completely invalid if KVM_MAX_VCPUS is too low (<256?). That sounds good to me. I would prefer to set the range from 1024 to 4096 in this patch.=